diff --git a/src/ifcparse/Ifc2x3.cpp b/src/ifcparse/Ifc2x3.cpp
index c0e35dc2de..249c055202 100644
--- a/src/ifcparse/Ifc2x3.cpp
+++ b/src/ifcparse/Ifc2x3.cpp
@@ -9015,9 +9015,9 @@ Ifc2x3::IfcActor::IfcActor(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory* v
 ::Ifc2x3::IfcRoleEnum::Value Ifc2x3::IfcActorRole::Role() const {  return ::Ifc2x3::IfcRoleEnum::FromString(*data_->getArgument(0)); }
 void Ifc2x3::IfcActorRole::setRole(::Ifc2x3::IfcRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcRoleEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcActorRole::UserDefinedRole() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcActorRole::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcActorRole::declaration() const { return *IFC2X3_IfcActorRole_type; }
@@ -9037,11 +9037,11 @@ Ifc2x3::IfcActuatorType::IfcActuatorType(std::string v1_GlobalId, ::Ifc2x3::IfcO
 
 // Function implementations for IfcAddress
 boost::optional< ::Ifc2x3::IfcAddressTypeEnum::Value > Ifc2x3::IfcAddress::Purpose() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } return ::Ifc2x3::IfcAddressTypeEnum::FromString(*data_->getArgument(0)); }
-void Ifc2x3::IfcAddress::setPurpose(boost::optional< ::Ifc2x3::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcAddressTypeEnum::ToString(*v)));data_->setArgument(0,attr);} }
+void Ifc2x3::IfcAddress::setPurpose(boost::optional< ::Ifc2x3::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcAddressTypeEnum::ToString(*v)));}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcAddress::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcAddress::UserDefinedPurpose() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc2x3::IfcPerson::list::ptr Ifc2x3::IfcAddress::OfPerson() const { return data_->getInverse(IFC2X3_IfcPerson_type, 7)->as<IfcPerson>(); }
 ::Ifc2x3::IfcOrganization::list::ptr Ifc2x3::IfcAddress::OfOrganization() const { return data_->getInverse(IFC2X3_IfcOrganization_type, 4)->as<IfcOrganization>(); }
@@ -9120,7 +9120,7 @@ Ifc2x3::IfcAnnotationCurveOccurrence::IfcAnnotationCurveOccurrence(::Ifc2x3::Ifc
 ::Ifc2x3::IfcCurve* Ifc2x3::IfcAnnotationFillArea::OuterBoundary() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc2x3::IfcCurve>(true); }
 void Ifc2x3::IfcAnnotationFillArea::setOuterBoundary(::Ifc2x3::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcCurve >::ptr > Ifc2x3::IfcAnnotationFillArea::InnerBoundaries() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc2x3::IfcCurve >(); }
-void Ifc2x3::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc2x3::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc2x3::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc2x3::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcAnnotationFillArea::declaration() const { return *IFC2X3_IfcAnnotationFillArea_type; }
@@ -9132,7 +9132,7 @@ Ifc2x3::IfcAnnotationFillArea::IfcAnnotationFillArea(::Ifc2x3::IfcCurve* v1_Oute
 ::Ifc2x3::IfcPoint* Ifc2x3::IfcAnnotationFillAreaOccurrence::FillStyleTarget() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc2x3::IfcPoint>(true); }
 void Ifc2x3::IfcAnnotationFillAreaOccurrence::setFillStyleTarget(::Ifc2x3::IfcPoint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< ::Ifc2x3::IfcGlobalOrLocalEnum::Value > Ifc2x3::IfcAnnotationFillAreaOccurrence::GlobalOrLocal() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc2x3::IfcGlobalOrLocalEnum::FromString(*data_->getArgument(4)); }
-void Ifc2x3::IfcAnnotationFillAreaOccurrence::setGlobalOrLocal(boost::optional< ::Ifc2x3::IfcGlobalOrLocalEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcGlobalOrLocalEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc2x3::IfcAnnotationFillAreaOccurrence::setGlobalOrLocal(boost::optional< ::Ifc2x3::IfcGlobalOrLocalEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcGlobalOrLocalEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcAnnotationFillAreaOccurrence::declaration() const { return *IFC2X3_IfcAnnotationFillAreaOccurrence_type; }
@@ -9202,9 +9202,9 @@ Ifc2x3::IfcApplication::IfcApplication(::Ifc2x3::IfcOrganization* v1_Application
 
 // Function implementations for IfcAppliedValue
 boost::optional< std::string > Ifc2x3::IfcAppliedValue::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcAppliedValue::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc2x3::IfcAppliedValueSelect* Ifc2x3::IfcAppliedValue::AppliedValue() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc2x3::IfcAppliedValueSelect>(true); }
 void Ifc2x3::IfcAppliedValue::setAppliedValue(::Ifc2x3::IfcAppliedValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcMeasureWithUnit* Ifc2x3::IfcAppliedValue::UnitBasis() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc2x3::IfcMeasureWithUnit>(true); }
@@ -9231,9 +9231,9 @@ void Ifc2x3::IfcAppliedValueRelationship::setComponents(aggregate_of< ::Ifc2x3::
 ::Ifc2x3::IfcArithmeticOperatorEnum::Value Ifc2x3::IfcAppliedValueRelationship::ArithmeticOperator() const {  return ::Ifc2x3::IfcArithmeticOperatorEnum::FromString(*data_->getArgument(2)); }
 void Ifc2x3::IfcAppliedValueRelationship::setArithmeticOperator(::Ifc2x3::IfcArithmeticOperatorEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcArithmeticOperatorEnum::ToString(v)));data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc2x3::IfcAppliedValueRelationship::Name() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcAppliedValueRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcAppliedValueRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc2x3::IfcAppliedValueRelationship::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcAppliedValueRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcAppliedValueRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcAppliedValueRelationship::declaration() const { return *IFC2X3_IfcAppliedValueRelationship_type; }
@@ -9243,15 +9243,15 @@ Ifc2x3::IfcAppliedValueRelationship::IfcAppliedValueRelationship(::Ifc2x3::IfcAp
 
 // Function implementations for IfcApproval
 boost::optional< std::string > Ifc2x3::IfcApproval::Description() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcApproval::ApprovalDateTime() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
 void Ifc2x3::IfcApproval::setApprovalDateTime(::Ifc2x3::IfcDateTimeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcApproval::ApprovalStatus() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcApproval::setApprovalStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcApproval::setApprovalStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc2x3::IfcApproval::ApprovalLevel() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcApproval::setApprovalLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcApproval::setApprovalLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc2x3::IfcApproval::ApprovalQualifier() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcApproval::setApprovalQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcApproval::setApprovalQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 std::string Ifc2x3::IfcApproval::Name() const {  std::string v = *data_->getArgument(5); return v; }
 void Ifc2x3::IfcApproval::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 std::string Ifc2x3::IfcApproval::Identifier() const {  std::string v = *data_->getArgument(6); return v; }
@@ -9298,7 +9298,7 @@ void Ifc2x3::IfcApprovalRelationship::setRelatedApproval(::Ifc2x3::IfcApproval*
 ::Ifc2x3::IfcApproval* Ifc2x3::IfcApprovalRelationship::RelatingApproval() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc2x3::IfcApproval>(true); }
 void Ifc2x3::IfcApprovalRelationship::setRelatingApproval(::Ifc2x3::IfcApproval* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcApprovalRelationship::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcApprovalRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcApprovalRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::string Ifc2x3::IfcApprovalRelationship::Name() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc2x3::IfcApprovalRelationship::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -9368,11 +9368,11 @@ Ifc2x3::IfcAsset::IfcAsset(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory* v
 double Ifc2x3::IfcAsymmetricIShapeProfileDef::TopFlangeWidth() const {  double v = *data_->getArgument(8); return v; }
 void Ifc2x3::IfcAsymmetricIShapeProfileDef::setTopFlangeWidth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcAsymmetricIShapeProfileDef::TopFlangeThickness() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcAsymmetricIShapeProfileDef::TopFlangeFilletRadius() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcAsymmetricIShapeProfileDef::CentreOfGravityInY() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcAsymmetricIShapeProfileDef::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcAsymmetricIShapeProfileDef::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcAsymmetricIShapeProfileDef::declaration() const { return *IFC2X3_IfcAsymmetricIShapeProfileDef_type; }
@@ -9516,7 +9516,7 @@ Ifc2x3::IfcBooleanResult::IfcBooleanResult(::Ifc2x3::IfcBooleanOperator::Value v
 
 // Function implementations for IfcBoundaryCondition
 boost::optional< std::string > Ifc2x3::IfcBoundaryCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcBoundaryCondition::declaration() const { return *IFC2X3_IfcBoundaryCondition_type; }
@@ -9526,17 +9526,17 @@ Ifc2x3::IfcBoundaryCondition::IfcBoundaryCondition(boost::optional< std::string
 
 // Function implementations for IfcBoundaryEdgeCondition
 boost::optional< double > Ifc2x3::IfcBoundaryEdgeCondition::LinearStiffnessByLengthX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcBoundaryEdgeCondition::setLinearStiffnessByLengthX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcBoundaryEdgeCondition::setLinearStiffnessByLengthX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryEdgeCondition::LinearStiffnessByLengthY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcBoundaryEdgeCondition::setLinearStiffnessByLengthY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcBoundaryEdgeCondition::setLinearStiffnessByLengthY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryEdgeCondition::LinearStiffnessByLengthZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcBoundaryEdgeCondition::setLinearStiffnessByLengthZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcBoundaryEdgeCondition::setLinearStiffnessByLengthZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryEdgeCondition::RotationalStiffnessByLengthX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcBoundaryEdgeCondition::setRotationalStiffnessByLengthX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcBoundaryEdgeCondition::setRotationalStiffnessByLengthX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryEdgeCondition::RotationalStiffnessByLengthY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcBoundaryEdgeCondition::setRotationalStiffnessByLengthY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcBoundaryEdgeCondition::setRotationalStiffnessByLengthY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryEdgeCondition::RotationalStiffnessByLengthZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcBoundaryEdgeCondition::setRotationalStiffnessByLengthZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcBoundaryEdgeCondition::setRotationalStiffnessByLengthZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcBoundaryEdgeCondition::declaration() const { return *IFC2X3_IfcBoundaryEdgeCondition_type; }
@@ -9546,11 +9546,11 @@ Ifc2x3::IfcBoundaryEdgeCondition::IfcBoundaryEdgeCondition(boost::optional< std:
 
 // Function implementations for IfcBoundaryFaceCondition
 boost::optional< double > Ifc2x3::IfcBoundaryFaceCondition::LinearStiffnessByAreaX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcBoundaryFaceCondition::setLinearStiffnessByAreaX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcBoundaryFaceCondition::setLinearStiffnessByAreaX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryFaceCondition::LinearStiffnessByAreaY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcBoundaryFaceCondition::setLinearStiffnessByAreaY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcBoundaryFaceCondition::setLinearStiffnessByAreaY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryFaceCondition::LinearStiffnessByAreaZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcBoundaryFaceCondition::setLinearStiffnessByAreaZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcBoundaryFaceCondition::setLinearStiffnessByAreaZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcBoundaryFaceCondition::declaration() const { return *IFC2X3_IfcBoundaryFaceCondition_type; }
@@ -9560,17 +9560,17 @@ Ifc2x3::IfcBoundaryFaceCondition::IfcBoundaryFaceCondition(boost::optional< std:
 
 // Function implementations for IfcBoundaryNodeCondition
 boost::optional< double > Ifc2x3::IfcBoundaryNodeCondition::LinearStiffnessX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcBoundaryNodeCondition::setLinearStiffnessX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcBoundaryNodeCondition::setLinearStiffnessX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryNodeCondition::LinearStiffnessY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcBoundaryNodeCondition::setLinearStiffnessY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcBoundaryNodeCondition::setLinearStiffnessY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryNodeCondition::LinearStiffnessZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcBoundaryNodeCondition::setLinearStiffnessZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcBoundaryNodeCondition::setLinearStiffnessZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryNodeCondition::RotationalStiffnessX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcBoundaryNodeCondition::setRotationalStiffnessX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcBoundaryNodeCondition::setRotationalStiffnessX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryNodeCondition::RotationalStiffnessY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcBoundaryNodeCondition::setRotationalStiffnessY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcBoundaryNodeCondition::setRotationalStiffnessY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcBoundaryNodeCondition::RotationalStiffnessZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcBoundaryNodeCondition::setRotationalStiffnessZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcBoundaryNodeCondition::setRotationalStiffnessZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcBoundaryNodeCondition::declaration() const { return *IFC2X3_IfcBoundaryNodeCondition_type; }
@@ -9580,7 +9580,7 @@ Ifc2x3::IfcBoundaryNodeCondition::IfcBoundaryNodeCondition(boost::optional< std:
 
 // Function implementations for IfcBoundaryNodeConditionWarping
 boost::optional< double > Ifc2x3::IfcBoundaryNodeConditionWarping::WarpingStiffness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcBoundaryNodeConditionWarping::setWarpingStiffness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcBoundaryNodeConditionWarping::setWarpingStiffness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcBoundaryNodeConditionWarping::declaration() const { return *IFC2X3_IfcBoundaryNodeConditionWarping_type; }
@@ -9632,9 +9632,9 @@ Ifc2x3::IfcBoxedHalfSpace::IfcBoxedHalfSpace(::Ifc2x3::IfcSurface* v1_BaseSurfac
 
 // Function implementations for IfcBuilding
 boost::optional< double > Ifc2x3::IfcBuilding::ElevationOfRefHeight() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcBuilding::ElevationOfTerrain() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc2x3::IfcPostalAddress* Ifc2x3::IfcBuilding::BuildingAddress() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc2x3::IfcPostalAddress>(true); }
 void Ifc2x3::IfcBuilding::setBuildingAddress(::Ifc2x3::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 
@@ -9670,7 +9670,7 @@ Ifc2x3::IfcBuildingElementPart::IfcBuildingElementPart(std::string v1_GlobalId,
 
 // Function implementations for IfcBuildingElementProxy
 boost::optional< ::Ifc2x3::IfcElementCompositionEnum::Value > Ifc2x3::IfcBuildingElementProxy::CompositionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc2x3::IfcElementCompositionEnum::FromString(*data_->getArgument(8)); }
-void Ifc2x3::IfcBuildingElementProxy::setCompositionType(boost::optional< ::Ifc2x3::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcElementCompositionEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc2x3::IfcBuildingElementProxy::setCompositionType(boost::optional< ::Ifc2x3::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcElementCompositionEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcBuildingElementProxy::declaration() const { return *IFC2X3_IfcBuildingElementProxy_type; }
@@ -9698,7 +9698,7 @@ Ifc2x3::IfcBuildingElementType::IfcBuildingElementType(std::string v1_GlobalId,
 
 // Function implementations for IfcBuildingStorey
 boost::optional< double > Ifc2x3::IfcBuildingStorey::Elevation() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcBuildingStorey::declaration() const { return *IFC2X3_IfcBuildingStorey_type; }
@@ -9716,9 +9716,9 @@ void Ifc2x3::IfcCShapeProfileDef::setWallThickness(double v) { {IfcWrite::IfcWri
 double Ifc2x3::IfcCShapeProfileDef::Girth() const {  double v = *data_->getArgument(6); return v; }
 void Ifc2x3::IfcCShapeProfileDef::setGirth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcCShapeProfileDef::InternalFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcCShapeProfileDef::CentreOfGravityInX() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcCShapeProfileDef::setCentreOfGravityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcCShapeProfileDef::setCentreOfGravityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcCShapeProfileDef::declaration() const { return *IFC2X3_IfcCShapeProfileDef_type; }
@@ -9788,7 +9788,7 @@ void Ifc2x3::IfcCartesianTransformationOperator::setAxis2(::Ifc2x3::IfcDirection
 ::Ifc2x3::IfcCartesianPoint* Ifc2x3::IfcCartesianTransformationOperator::LocalOrigin() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc2x3::IfcCartesianPoint>(true); }
 void Ifc2x3::IfcCartesianTransformationOperator::setLocalOrigin(::Ifc2x3::IfcCartesianPoint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcCartesianTransformationOperator::Scale() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcCartesianTransformationOperator::declaration() const { return *IFC2X3_IfcCartesianTransformationOperator_type; }
@@ -9806,7 +9806,7 @@ Ifc2x3::IfcCartesianTransformationOperator2D::IfcCartesianTransformationOperator
 
 // Function implementations for IfcCartesianTransformationOperator2DnonUniform
 boost::optional< double > Ifc2x3::IfcCartesianTransformationOperator2DnonUniform::Scale2() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcCartesianTransformationOperator2DnonUniform::declaration() const { return *IFC2X3_IfcCartesianTransformationOperator2DnonUniform_type; }
@@ -9826,9 +9826,9 @@ Ifc2x3::IfcCartesianTransformationOperator3D::IfcCartesianTransformationOperator
 
 // Function implementations for IfcCartesianTransformationOperator3DnonUniform
 boost::optional< double > Ifc2x3::IfcCartesianTransformationOperator3DnonUniform::Scale2() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcCartesianTransformationOperator3DnonUniform::Scale3() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcCartesianTransformationOperator3DnonUniform::declaration() const { return *IFC2X3_IfcCartesianTransformationOperator3DnonUniform_type; }
@@ -9848,9 +9848,9 @@ Ifc2x3::IfcCenterLineProfileDef::IfcCenterLineProfileDef(::Ifc2x3::IfcProfileTyp
 
 // Function implementations for IfcChamferEdgeFeature
 boost::optional< double > Ifc2x3::IfcChamferEdgeFeature::Width() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcChamferEdgeFeature::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcChamferEdgeFeature::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcChamferEdgeFeature::Height() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcChamferEdgeFeature::setHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcChamferEdgeFeature::setHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcChamferEdgeFeature::declaration() const { return *IFC2X3_IfcChamferEdgeFeature_type; }
@@ -10007,7 +10007,7 @@ Ifc2x3::IfcColourRgb::IfcColourRgb(boost::optional< std::string > v1_Name, doubl
 
 // Function implementations for IfcColourSpecification
 boost::optional< std::string > Ifc2x3::IfcColourSpecification::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcColourSpecification::declaration() const { return *IFC2X3_IfcColourSpecification_type; }
@@ -10076,7 +10076,7 @@ Ifc2x3::IfcCompositeCurveSegment::IfcCompositeCurveSegment(::Ifc2x3::IfcTransiti
 aggregate_of< ::Ifc2x3::IfcProfileDef >::ptr Ifc2x3::IfcCompositeProfileDef::Profiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc2x3::IfcProfileDef >(); }
 void Ifc2x3::IfcCompositeProfileDef::setProfiles(aggregate_of< ::Ifc2x3::IfcProfileDef >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc2x3::IfcCompositeProfileDef::Label() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcCompositeProfileDef::declaration() const { return *IFC2X3_IfcCompositeProfileDef_type; }
@@ -10166,11 +10166,11 @@ Ifc2x3::IfcConnectionGeometry::IfcConnectionGeometry() : IfcUtil::IfcBaseEntity(
 
 // Function implementations for IfcConnectionPointEccentricity
 boost::optional< double > Ifc2x3::IfcConnectionPointEccentricity::EccentricityInX() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcConnectionPointEccentricity::EccentricityInY() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcConnectionPointEccentricity::EccentricityInZ() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcConnectionPointEccentricity::declaration() const { return *IFC2X3_IfcConnectionPointEccentricity_type; }
@@ -10220,17 +10220,17 @@ Ifc2x3::IfcConnectionSurfaceGeometry::IfcConnectionSurfaceGeometry(::Ifc2x3::Ifc
 std::string Ifc2x3::IfcConstraint::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc2x3::IfcConstraint::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcConstraint::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc2x3::IfcConstraintEnum::Value Ifc2x3::IfcConstraint::ConstraintGrade() const {  return ::Ifc2x3::IfcConstraintEnum::FromString(*data_->getArgument(2)); }
 void Ifc2x3::IfcConstraint::setConstraintGrade(::Ifc2x3::IfcConstraintEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcConstraintEnum::ToString(v)));data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc2x3::IfcConstraint::ConstraintSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc2x3::IfcActorSelect* Ifc2x3::IfcConstraint::CreatingActor() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc2x3::IfcActorSelect>(true); }
 void Ifc2x3::IfcConstraint::setCreatingActor(::Ifc2x3::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcConstraint::CreationTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
 void Ifc2x3::IfcConstraint::setCreationTime(::Ifc2x3::IfcDateTimeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc2x3::IfcConstraint::UserDefinedGrade() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc2x3::IfcConstraintClassificationRelationship::list::ptr Ifc2x3::IfcConstraint::ClassifiedAs() const { return data_->getInverse(IFC2X3_IfcConstraintClassificationRelationship_type, 0)->as<IfcConstraintClassificationRelationship>(); }
 ::Ifc2x3::IfcConstraintRelationship::list::ptr Ifc2x3::IfcConstraint::RelatesConstraints() const { return data_->getInverse(IFC2X3_IfcConstraintRelationship_type, 2)->as<IfcConstraintRelationship>(); }
@@ -10246,9 +10246,9 @@ Ifc2x3::IfcConstraint::IfcConstraint(std::string v1_Name, boost::optional< std::
 
 // Function implementations for IfcConstraintAggregationRelationship
 boost::optional< std::string > Ifc2x3::IfcConstraintAggregationRelationship::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcConstraintAggregationRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcConstraintAggregationRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcConstraintAggregationRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcConstraintAggregationRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcConstraintAggregationRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc2x3::IfcConstraint* Ifc2x3::IfcConstraintAggregationRelationship::RelatingConstraint() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc2x3::IfcConstraint>(true); }
 void Ifc2x3::IfcConstraintAggregationRelationship::setRelatingConstraint(::Ifc2x3::IfcConstraint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc2x3::IfcConstraint >::ptr Ifc2x3::IfcConstraintAggregationRelationship::RelatedConstraints() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc2x3::IfcConstraint >(); }
@@ -10276,9 +10276,9 @@ Ifc2x3::IfcConstraintClassificationRelationship::IfcConstraintClassificationRela
 
 // Function implementations for IfcConstraintRelationship
 boost::optional< std::string > Ifc2x3::IfcConstraintRelationship::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcConstraintRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcConstraintRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcConstraintRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcConstraintRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcConstraintRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc2x3::IfcConstraint* Ifc2x3::IfcConstraintRelationship::RelatingConstraint() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc2x3::IfcConstraint>(true); }
 void Ifc2x3::IfcConstraintRelationship::setRelatingConstraint(::Ifc2x3::IfcConstraint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc2x3::IfcConstraint >::ptr Ifc2x3::IfcConstraintRelationship::RelatedConstraints() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc2x3::IfcConstraint >(); }
@@ -10300,9 +10300,9 @@ Ifc2x3::IfcConstructionEquipmentResource::IfcConstructionEquipmentResource(std::
 
 // Function implementations for IfcConstructionMaterialResource
 boost::optional< aggregate_of_instance::ptr > Ifc2x3::IfcConstructionMaterialResource::Suppliers() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcConstructionMaterialResource::setSuppliers(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcConstructionMaterialResource::setSuppliers(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcConstructionMaterialResource::UsageRatio() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcConstructionMaterialResource::setUsageRatio(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcConstructionMaterialResource::setUsageRatio(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcConstructionMaterialResource::declaration() const { return *IFC2X3_IfcConstructionMaterialResource_type; }
@@ -10320,11 +10320,11 @@ Ifc2x3::IfcConstructionProductResource::IfcConstructionProductResource(std::stri
 
 // Function implementations for IfcConstructionResource
 boost::optional< std::string > Ifc2x3::IfcConstructionResource::ResourceIdentifier() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcConstructionResource::setResourceIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcConstructionResource::setResourceIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc2x3::IfcConstructionResource::ResourceGroup() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcConstructionResource::setResourceGroup(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcConstructionResource::setResourceGroup(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< ::Ifc2x3::IfcResourceConsumptionEnum::Value > Ifc2x3::IfcConstructionResource::ResourceConsumption() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc2x3::IfcResourceConsumptionEnum::FromString(*data_->getArgument(7)); }
-void Ifc2x3::IfcConstructionResource::setResourceConsumption(boost::optional< ::Ifc2x3::IfcResourceConsumptionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcResourceConsumptionEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc2x3::IfcConstructionResource::setResourceConsumption(boost::optional< ::Ifc2x3::IfcResourceConsumptionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcResourceConsumptionEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 ::Ifc2x3::IfcMeasureWithUnit* Ifc2x3::IfcConstructionResource::BaseQuantity() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc2x3::IfcMeasureWithUnit>(true); }
 void Ifc2x3::IfcConstructionResource::setBaseQuantity(::Ifc2x3::IfcMeasureWithUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -10399,7 +10399,7 @@ Ifc2x3::IfcCoolingTowerType::IfcCoolingTowerType(std::string v1_GlobalId, ::Ifc2
 int Ifc2x3::IfcCoordinatedUniversalTimeOffset::HourOffset() const {  int v = *data_->getArgument(0); return v; }
 void Ifc2x3::IfcCoordinatedUniversalTimeOffset::setHourOffset(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< int > Ifc2x3::IfcCoordinatedUniversalTimeOffset::MinuteOffset() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } int v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcCoordinatedUniversalTimeOffset::setMinuteOffset(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcCoordinatedUniversalTimeOffset::setMinuteOffset(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc2x3::IfcAheadOrBehind::Value Ifc2x3::IfcCoordinatedUniversalTimeOffset::Sense() const {  return ::Ifc2x3::IfcAheadOrBehind::FromString(*data_->getArgument(2)); }
 void Ifc2x3::IfcCoordinatedUniversalTimeOffset::setSense(::Ifc2x3::IfcAheadOrBehind::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcAheadOrBehind::ToString(v)));data_->setArgument(2,attr);} }
 
@@ -10425,9 +10425,9 @@ void Ifc2x3::IfcCostSchedule::setPreparedBy(::Ifc2x3::IfcActorSelect* v) { {IfcW
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcCostSchedule::SubmittedOn() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
 void Ifc2x3::IfcCostSchedule::setSubmittedOn(::Ifc2x3::IfcDateTimeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc2x3::IfcCostSchedule::Status() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc2x3::IfcCostSchedule::TargetUsers() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcCostSchedule::setTargetUsers(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcCostSchedule::setTargetUsers(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcCostSchedule::UpdateDate() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
 void Ifc2x3::IfcCostSchedule::setUpdateDate(::Ifc2x3::IfcDateTimeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 std::string Ifc2x3::IfcCostSchedule::ID() const {  std::string v = *data_->getArgument(11); return v; }
@@ -10445,7 +10445,7 @@ Ifc2x3::IfcCostSchedule::IfcCostSchedule(std::string v1_GlobalId, ::Ifc2x3::IfcO
 std::string Ifc2x3::IfcCostValue::CostType() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc2x3::IfcCostValue::setCostType(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc2x3::IfcCostValue::Condition() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcCostValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcCostValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcCostValue::declaration() const { return *IFC2X3_IfcCostValue_type; }
@@ -10455,7 +10455,7 @@ Ifc2x3::IfcCostValue::IfcCostValue(boost::optional< std::string > v1_Name, boost
 
 // Function implementations for IfcCovering
 boost::optional< ::Ifc2x3::IfcCoveringTypeEnum::Value > Ifc2x3::IfcCovering::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc2x3::IfcCoveringTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc2x3::IfcCovering::setPredefinedType(boost::optional< ::Ifc2x3::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcCoveringTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc2x3::IfcCovering::setPredefinedType(boost::optional< ::Ifc2x3::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcCoveringTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc2x3::IfcRelCoversSpaces::list::ptr Ifc2x3::IfcCovering::CoversSpaces() const { return data_->getInverse(IFC2X3_IfcRelCoversSpaces_type, 5)->as<IfcRelCoversSpaces>(); }
 ::Ifc2x3::IfcRelCoversBldgElements::list::ptr Ifc2x3::IfcCovering::Covers() const { return data_->getInverse(IFC2X3_IfcRelCoversBldgElements_type, 5)->as<IfcRelCoversBldgElements>(); }
@@ -10481,7 +10481,7 @@ void Ifc2x3::IfcCraneRailAShapeProfileDef::setOverallHeight(double v) { {IfcWrit
 double Ifc2x3::IfcCraneRailAShapeProfileDef::BaseWidth2() const {  double v = *data_->getArgument(4); return v; }
 void Ifc2x3::IfcCraneRailAShapeProfileDef::setBaseWidth2(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcCraneRailAShapeProfileDef::Radius() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcCraneRailAShapeProfileDef::setRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcCraneRailAShapeProfileDef::setRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 double Ifc2x3::IfcCraneRailAShapeProfileDef::HeadWidth() const {  double v = *data_->getArgument(6); return v; }
 void Ifc2x3::IfcCraneRailAShapeProfileDef::setHeadWidth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 double Ifc2x3::IfcCraneRailAShapeProfileDef::HeadDepth2() const {  double v = *data_->getArgument(7); return v; }
@@ -10499,7 +10499,7 @@ void Ifc2x3::IfcCraneRailAShapeProfileDef::setBaseDepth2(double v) { {IfcWrite::
 double Ifc2x3::IfcCraneRailAShapeProfileDef::BaseDepth3() const {  double v = *data_->getArgument(13); return v; }
 void Ifc2x3::IfcCraneRailAShapeProfileDef::setBaseDepth3(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 boost::optional< double > Ifc2x3::IfcCraneRailAShapeProfileDef::CentreOfGravityInY() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc2x3::IfcCraneRailAShapeProfileDef::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc2x3::IfcCraneRailAShapeProfileDef::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcCraneRailAShapeProfileDef::declaration() const { return *IFC2X3_IfcCraneRailAShapeProfileDef_type; }
@@ -10513,7 +10513,7 @@ void Ifc2x3::IfcCraneRailFShapeProfileDef::setOverallHeight(double v) { {IfcWrit
 double Ifc2x3::IfcCraneRailFShapeProfileDef::HeadWidth() const {  double v = *data_->getArgument(4); return v; }
 void Ifc2x3::IfcCraneRailFShapeProfileDef::setHeadWidth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcCraneRailFShapeProfileDef::Radius() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcCraneRailFShapeProfileDef::setRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcCraneRailFShapeProfileDef::setRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 double Ifc2x3::IfcCraneRailFShapeProfileDef::HeadDepth2() const {  double v = *data_->getArgument(6); return v; }
 void Ifc2x3::IfcCraneRailFShapeProfileDef::setHeadDepth2(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 double Ifc2x3::IfcCraneRailFShapeProfileDef::HeadDepth3() const {  double v = *data_->getArgument(7); return v; }
@@ -10525,7 +10525,7 @@ void Ifc2x3::IfcCraneRailFShapeProfileDef::setBaseDepth1(double v) { {IfcWrite::
 double Ifc2x3::IfcCraneRailFShapeProfileDef::BaseDepth2() const {  double v = *data_->getArgument(10); return v; }
 void Ifc2x3::IfcCraneRailFShapeProfileDef::setBaseDepth2(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcCraneRailFShapeProfileDef::CentreOfGravityInY() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcCraneRailFShapeProfileDef::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcCraneRailFShapeProfileDef::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcCraneRailFShapeProfileDef::declaration() const { return *IFC2X3_IfcCraneRailFShapeProfileDef_type; }
@@ -10635,7 +10635,7 @@ Ifc2x3::IfcCurveStyle::IfcCurveStyle(boost::optional< std::string > v1_Name, ::I
 
 // Function implementations for IfcCurveStyleFont
 boost::optional< std::string > Ifc2x3::IfcCurveStyleFont::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc2x3::IfcCurveStyleFontPattern >::ptr Ifc2x3::IfcCurveStyleFont::PatternList() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc2x3::IfcCurveStyleFontPattern >(); }
 void Ifc2x3::IfcCurveStyleFont::setPatternList(aggregate_of< ::Ifc2x3::IfcCurveStyleFontPattern >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -10647,7 +10647,7 @@ Ifc2x3::IfcCurveStyleFont::IfcCurveStyleFont(boost::optional< std::string > v1_N
 
 // Function implementations for IfcCurveStyleFontAndScaling
 boost::optional< std::string > Ifc2x3::IfcCurveStyleFontAndScaling::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc2x3::IfcCurveStyleFontSelect* Ifc2x3::IfcCurveStyleFontAndScaling::CurveFont() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc2x3::IfcCurveStyleFontSelect>(true); }
 void Ifc2x3::IfcCurveStyleFontAndScaling::setCurveFont(::Ifc2x3::IfcCurveStyleFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 double Ifc2x3::IfcCurveStyleFontAndScaling::CurveFontScaling() const {  double v = *data_->getArgument(2); return v; }
@@ -10711,7 +10711,7 @@ void Ifc2x3::IfcDerivedProfileDef::setParentProfile(::Ifc2x3::IfcProfileDef* v)
 ::Ifc2x3::IfcCartesianTransformationOperator2D* Ifc2x3::IfcDerivedProfileDef::Operator() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc2x3::IfcCartesianTransformationOperator2D>(true); }
 void Ifc2x3::IfcDerivedProfileDef::setOperator(::Ifc2x3::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDerivedProfileDef::Label() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcDerivedProfileDef::declaration() const { return *IFC2X3_IfcDerivedProfileDef_type; }
@@ -10725,7 +10725,7 @@ void Ifc2x3::IfcDerivedUnit::setElements(aggregate_of< ::Ifc2x3::IfcDerivedUnitE
 ::Ifc2x3::IfcDerivedUnitEnum::Value Ifc2x3::IfcDerivedUnit::UnitType() const {  return ::Ifc2x3::IfcDerivedUnitEnum::FromString(*data_->getArgument(1)); }
 void Ifc2x3::IfcDerivedUnit::setUnitType(::Ifc2x3::IfcDerivedUnitEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcDerivedUnitEnum::ToString(v)));data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDerivedUnit::UserDefinedType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcDerivedUnit::declaration() const { return *IFC2X3_IfcDerivedUnit_type; }
@@ -10864,7 +10864,7 @@ Ifc2x3::IfcDistributionChamberElementType::IfcDistributionChamberElementType(std
 
 // Function implementations for IfcDistributionControlElement
 boost::optional< std::string > Ifc2x3::IfcDistributionControlElement::ControlElementId() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcDistributionControlElement::setControlElementId(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcDistributionControlElement::setControlElementId(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc2x3::IfcRelFlowControlElements::list::ptr Ifc2x3::IfcDistributionControlElement::AssignedToFlowElement() const { return data_->getInverse(IFC2X3_IfcRelFlowControlElements_type, 4)->as<IfcRelFlowControlElements>(); }
 
@@ -10916,7 +10916,7 @@ Ifc2x3::IfcDistributionFlowElementType::IfcDistributionFlowElementType(std::stri
 
 // Function implementations for IfcDistributionPort
 boost::optional< ::Ifc2x3::IfcFlowDirectionEnum::Value > Ifc2x3::IfcDistributionPort::FlowDirection() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc2x3::IfcFlowDirectionEnum::FromString(*data_->getArgument(7)); }
-void Ifc2x3::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc2x3::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcFlowDirectionEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc2x3::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc2x3::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcFlowDirectionEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcDistributionPort::declaration() const { return *IFC2X3_IfcDistributionPort_type; }
@@ -10926,11 +10926,11 @@ Ifc2x3::IfcDistributionPort::IfcDistributionPort(std::string v1_GlobalId, ::Ifc2
 
 // Function implementations for IfcDocumentElectronicFormat
 boost::optional< std::string > Ifc2x3::IfcDocumentElectronicFormat::FileExtension() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcDocumentElectronicFormat::setFileExtension(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcDocumentElectronicFormat::setFileExtension(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDocumentElectronicFormat::MimeContentType() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcDocumentElectronicFormat::setMimeContentType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcDocumentElectronicFormat::setMimeContentType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDocumentElectronicFormat::MimeSubtype() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcDocumentElectronicFormat::setMimeSubtype(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcDocumentElectronicFormat::setMimeSubtype(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcDocumentElectronicFormat::declaration() const { return *IFC2X3_IfcDocumentElectronicFormat_type; }
@@ -10944,21 +10944,21 @@ void Ifc2x3::IfcDocumentInformation::setDocumentId(std::string v) { {IfcWrite::I
 std::string Ifc2x3::IfcDocumentInformation::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc2x3::IfcDocumentInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDocumentInformation::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcDocumentReference >::ptr > Ifc2x3::IfcDocumentInformation::DocumentReferences() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc2x3::IfcDocumentReference >(); }
-void Ifc2x3::IfcDocumentInformation::setDocumentReferences(boost::optional< aggregate_of< ::Ifc2x3::IfcDocumentReference >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(3,attr);} }
+void Ifc2x3::IfcDocumentInformation::setDocumentReferences(boost::optional< aggregate_of< ::Ifc2x3::IfcDocumentReference >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDocumentInformation::Purpose() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDocumentInformation::IntendedUse() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDocumentInformation::Scope() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDocumentInformation::Revision() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc2x3::IfcActorSelect* Ifc2x3::IfcDocumentInformation::DocumentOwner() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc2x3::IfcActorSelect>(true); }
 void Ifc2x3::IfcDocumentInformation::setDocumentOwner(::Ifc2x3::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc2x3::IfcDocumentInformation::Editors() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 ::Ifc2x3::IfcDateAndTime* Ifc2x3::IfcDocumentInformation::CreationTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc2x3::IfcDateAndTime>(true); }
 void Ifc2x3::IfcDocumentInformation::setCreationTime(::Ifc2x3::IfcDateAndTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 ::Ifc2x3::IfcDateAndTime* Ifc2x3::IfcDocumentInformation::LastRevisionTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc2x3::IfcDateAndTime>(true); }
@@ -10970,9 +10970,9 @@ void Ifc2x3::IfcDocumentInformation::setValidFrom(::Ifc2x3::IfcCalendarDate* v)
 ::Ifc2x3::IfcCalendarDate* Ifc2x3::IfcDocumentInformation::ValidUntil() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(14)))->as<::Ifc2x3::IfcCalendarDate>(true); }
 void Ifc2x3::IfcDocumentInformation::setValidUntil(::Ifc2x3::IfcCalendarDate* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(14,attr);} }
 boost::optional< ::Ifc2x3::IfcDocumentConfidentialityEnum::Value > Ifc2x3::IfcDocumentInformation::Confidentiality() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } return ::Ifc2x3::IfcDocumentConfidentialityEnum::FromString(*data_->getArgument(15)); }
-void Ifc2x3::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc2x3::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcDocumentConfidentialityEnum::ToString(*v)));data_->setArgument(15,attr);} }
+void Ifc2x3::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc2x3::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcDocumentConfidentialityEnum::ToString(*v)));}data_->setArgument(15,attr);} }
 boost::optional< ::Ifc2x3::IfcDocumentStatusEnum::Value > Ifc2x3::IfcDocumentInformation::Status() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } return ::Ifc2x3::IfcDocumentStatusEnum::FromString(*data_->getArgument(16)); }
-void Ifc2x3::IfcDocumentInformation::setStatus(boost::optional< ::Ifc2x3::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcDocumentStatusEnum::ToString(*v)));data_->setArgument(16,attr);} }
+void Ifc2x3::IfcDocumentInformation::setStatus(boost::optional< ::Ifc2x3::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcDocumentStatusEnum::ToString(*v)));}data_->setArgument(16,attr);} }
 
 ::Ifc2x3::IfcDocumentInformationRelationship::list::ptr Ifc2x3::IfcDocumentInformation::IsPointedTo() const { return data_->getInverse(IFC2X3_IfcDocumentInformationRelationship_type, 1)->as<IfcDocumentInformationRelationship>(); }
 ::Ifc2x3::IfcDocumentInformationRelationship::list::ptr Ifc2x3::IfcDocumentInformation::IsPointer() const { return data_->getInverse(IFC2X3_IfcDocumentInformationRelationship_type, 0)->as<IfcDocumentInformationRelationship>(); }
@@ -10988,7 +10988,7 @@ void Ifc2x3::IfcDocumentInformationRelationship::setRelatingDocument(::Ifc2x3::I
 aggregate_of< ::Ifc2x3::IfcDocumentInformation >::ptr Ifc2x3::IfcDocumentInformationRelationship::RelatedDocuments() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc2x3::IfcDocumentInformation >(); }
 void Ifc2x3::IfcDocumentInformationRelationship::setRelatedDocuments(aggregate_of< ::Ifc2x3::IfcDocumentInformation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDocumentInformationRelationship::RelationshipType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcDocumentInformationRelationship::declaration() const { return *IFC2X3_IfcDocumentInformationRelationship_type; }
@@ -11007,9 +11007,9 @@ Ifc2x3::IfcDocumentReference::IfcDocumentReference(boost::optional< std::string
 
 // Function implementations for IfcDoor
 boost::optional< double > Ifc2x3::IfcDoor::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcDoor::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcDoor::declaration() const { return *IFC2X3_IfcDoor_type; }
@@ -11019,25 +11019,25 @@ Ifc2x3::IfcDoor::IfcDoor(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory* v2_
 
 // Function implementations for IfcDoorLiningProperties
 boost::optional< double > Ifc2x3::IfcDoorLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcDoorLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcDoorLiningProperties::ThresholdDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcDoorLiningProperties::ThresholdThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcDoorLiningProperties::TransomThickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcDoorLiningProperties::TransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcDoorLiningProperties::LiningOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcDoorLiningProperties::ThresholdOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc2x3::IfcDoorLiningProperties::CasingThickness() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc2x3::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc2x3::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc2x3::IfcDoorLiningProperties::CasingDepth() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc2x3::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc2x3::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 ::Ifc2x3::IfcShapeAspect* Ifc2x3::IfcDoorLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(14)))->as<::Ifc2x3::IfcShapeAspect>(true); }
 void Ifc2x3::IfcDoorLiningProperties::setShapeAspectStyle(::Ifc2x3::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(14,attr);} }
 
@@ -11049,11 +11049,11 @@ Ifc2x3::IfcDoorLiningProperties::IfcDoorLiningProperties(std::string v1_GlobalId
 
 // Function implementations for IfcDoorPanelProperties
 boost::optional< double > Ifc2x3::IfcDoorPanelProperties::PanelDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc2x3::IfcDoorPanelOperationEnum::Value Ifc2x3::IfcDoorPanelProperties::PanelOperation() const {  return ::Ifc2x3::IfcDoorPanelOperationEnum::FromString(*data_->getArgument(5)); }
 void Ifc2x3::IfcDoorPanelProperties::setPanelOperation(::Ifc2x3::IfcDoorPanelOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcDoorPanelOperationEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcDoorPanelProperties::PanelWidth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc2x3::IfcDoorPanelPositionEnum::Value Ifc2x3::IfcDoorPanelProperties::PanelPosition() const {  return ::Ifc2x3::IfcDoorPanelPositionEnum::FromString(*data_->getArgument(7)); }
 void Ifc2x3::IfcDoorPanelProperties::setPanelPosition(::Ifc2x3::IfcDoorPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcDoorPanelPositionEnum::ToString(v)));data_->setArgument(7,attr);} }
 ::Ifc2x3::IfcShapeAspect* Ifc2x3::IfcDoorPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc2x3::IfcShapeAspect>(true); }
@@ -11095,9 +11095,9 @@ Ifc2x3::IfcDraughtingCallout::IfcDraughtingCallout(aggregate_of_instance::ptr v1
 
 // Function implementations for IfcDraughtingCalloutRelationship
 boost::optional< std::string > Ifc2x3::IfcDraughtingCalloutRelationship::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcDraughtingCalloutRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcDraughtingCalloutRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcDraughtingCalloutRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcDraughtingCalloutRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcDraughtingCalloutRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc2x3::IfcDraughtingCallout* Ifc2x3::IfcDraughtingCalloutRelationship::RelatingDraughtingCallout() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc2x3::IfcDraughtingCallout>(true); }
 void Ifc2x3::IfcDraughtingCalloutRelationship::setRelatingDraughtingCallout(::Ifc2x3::IfcDraughtingCallout* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcDraughtingCallout* Ifc2x3::IfcDraughtingCalloutRelationship::RelatedDraughtingCallout() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc2x3::IfcDraughtingCallout>(true); }
@@ -11189,7 +11189,7 @@ Ifc2x3::IfcEdgeCurve::IfcEdgeCurve(::Ifc2x3::IfcVertex* v1_EdgeStart, ::Ifc2x3::
 
 // Function implementations for IfcEdgeFeature
 boost::optional< double > Ifc2x3::IfcEdgeFeature::FeatureLength() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcEdgeFeature::setFeatureLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcEdgeFeature::setFeatureLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcEdgeFeature::declaration() const { return *IFC2X3_IfcEdgeFeature_type; }
@@ -11221,7 +11221,7 @@ Ifc2x3::IfcElectricApplianceType::IfcElectricApplianceType(std::string v1_Global
 ::Ifc2x3::IfcElectricDistributionPointFunctionEnum::Value Ifc2x3::IfcElectricDistributionPoint::DistributionPointFunction() const {  return ::Ifc2x3::IfcElectricDistributionPointFunctionEnum::FromString(*data_->getArgument(8)); }
 void Ifc2x3::IfcElectricDistributionPoint::setDistributionPointFunction(::Ifc2x3::IfcElectricDistributionPointFunctionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcElectricDistributionPointFunctionEnum::ToString(v)));data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc2x3::IfcElectricDistributionPoint::UserDefinedFunction() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcElectricDistributionPoint::setUserDefinedFunction(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcElectricDistributionPoint::setUserDefinedFunction(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcElectricDistributionPoint::declaration() const { return *IFC2X3_IfcElectricDistributionPoint_type; }
@@ -11281,19 +11281,19 @@ Ifc2x3::IfcElectricTimeControlType::IfcElectricTimeControlType(std::string v1_Gl
 
 // Function implementations for IfcElectricalBaseProperties
 boost::optional< ::Ifc2x3::IfcElectricCurrentEnum::Value > Ifc2x3::IfcElectricalBaseProperties::ElectricCurrentType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc2x3::IfcElectricCurrentEnum::FromString(*data_->getArgument(6)); }
-void Ifc2x3::IfcElectricalBaseProperties::setElectricCurrentType(boost::optional< ::Ifc2x3::IfcElectricCurrentEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcElectricCurrentEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc2x3::IfcElectricalBaseProperties::setElectricCurrentType(boost::optional< ::Ifc2x3::IfcElectricCurrentEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcElectricCurrentEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 double Ifc2x3::IfcElectricalBaseProperties::InputVoltage() const {  double v = *data_->getArgument(7); return v; }
 void Ifc2x3::IfcElectricalBaseProperties::setInputVoltage(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 double Ifc2x3::IfcElectricalBaseProperties::InputFrequency() const {  double v = *data_->getArgument(8); return v; }
 void Ifc2x3::IfcElectricalBaseProperties::setInputFrequency(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcElectricalBaseProperties::FullLoadCurrent() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcElectricalBaseProperties::setFullLoadCurrent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcElectricalBaseProperties::setFullLoadCurrent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcElectricalBaseProperties::MinimumCircuitCurrent() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcElectricalBaseProperties::setMinimumCircuitCurrent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcElectricalBaseProperties::setMinimumCircuitCurrent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcElectricalBaseProperties::MaximumPowerInput() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcElectricalBaseProperties::setMaximumPowerInput(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcElectricalBaseProperties::setMaximumPowerInput(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc2x3::IfcElectricalBaseProperties::RatedPowerInput() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc2x3::IfcElectricalBaseProperties::setRatedPowerInput(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc2x3::IfcElectricalBaseProperties::setRatedPowerInput(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 int Ifc2x3::IfcElectricalBaseProperties::InputPhase() const {  int v = *data_->getArgument(13); return v; }
 void Ifc2x3::IfcElectricalBaseProperties::setInputPhase(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -11321,7 +11321,7 @@ Ifc2x3::IfcElectricalElement::IfcElectricalElement(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcElement
 boost::optional< std::string > Ifc2x3::IfcElement::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc2x3::IfcRelConnectsStructuralElement::list::ptr Ifc2x3::IfcElement::HasStructuralMember() const { return data_->getInverse(IFC2X3_IfcRelConnectsStructuralElement_type, 4)->as<IfcRelConnectsStructuralElement>(); }
 ::Ifc2x3::IfcRelFillsElement::list::ptr Ifc2x3::IfcElement::FillsVoids() const { return data_->getInverse(IFC2X3_IfcRelFillsElement_type, 5)->as<IfcRelFillsElement>(); }
@@ -11343,7 +11343,7 @@ Ifc2x3::IfcElement::IfcElement(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistor
 
 // Function implementations for IfcElementAssembly
 boost::optional< ::Ifc2x3::IfcAssemblyPlaceEnum::Value > Ifc2x3::IfcElementAssembly::AssemblyPlace() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc2x3::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(8)); }
-void Ifc2x3::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc2x3::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcAssemblyPlaceEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc2x3::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc2x3::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcAssemblyPlaceEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 ::Ifc2x3::IfcElementAssemblyTypeEnum::Value Ifc2x3::IfcElementAssembly::PredefinedType() const {  return ::Ifc2x3::IfcElementAssemblyTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc2x3::IfcElementAssembly::setPredefinedType(::Ifc2x3::IfcElementAssemblyTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcElementAssemblyTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 
@@ -11371,7 +11371,7 @@ Ifc2x3::IfcElementComponentType::IfcElementComponentType(std::string v1_GlobalId
 
 // Function implementations for IfcElementQuantity
 boost::optional< std::string > Ifc2x3::IfcElementQuantity::MethodOfMeasurement() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc2x3::IfcPhysicalQuantity >::ptr Ifc2x3::IfcElementQuantity::Quantities() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc2x3::IfcPhysicalQuantity >(); }
 void Ifc2x3::IfcElementQuantity::setQuantities(aggregate_of< ::Ifc2x3::IfcPhysicalQuantity >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -11383,7 +11383,7 @@ Ifc2x3::IfcElementQuantity::IfcElementQuantity(std::string v1_GlobalId, ::Ifc2x3
 
 // Function implementations for IfcElementType
 boost::optional< std::string > Ifc2x3::IfcElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcElementType::declaration() const { return *IFC2X3_IfcElementType_type; }
@@ -11443,9 +11443,9 @@ Ifc2x3::IfcEnergyConversionDeviceType::IfcEnergyConversionDeviceType(std::string
 
 // Function implementations for IfcEnergyProperties
 boost::optional< ::Ifc2x3::IfcEnergySequenceEnum::Value > Ifc2x3::IfcEnergyProperties::EnergySequence() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc2x3::IfcEnergySequenceEnum::FromString(*data_->getArgument(4)); }
-void Ifc2x3::IfcEnergyProperties::setEnergySequence(boost::optional< ::Ifc2x3::IfcEnergySequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcEnergySequenceEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc2x3::IfcEnergyProperties::setEnergySequence(boost::optional< ::Ifc2x3::IfcEnergySequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcEnergySequenceEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc2x3::IfcEnergyProperties::UserDefinedEnergySequence() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcEnergyProperties::setUserDefinedEnergySequence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcEnergyProperties::setUserDefinedEnergySequence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcEnergyProperties::declaration() const { return *IFC2X3_IfcEnergyProperties_type; }
@@ -11459,7 +11459,7 @@ void Ifc2x3::IfcEnvironmentalImpactValue::setImpactType(std::string v) { {IfcWri
 ::Ifc2x3::IfcEnvironmentalImpactCategoryEnum::Value Ifc2x3::IfcEnvironmentalImpactValue::Category() const {  return ::Ifc2x3::IfcEnvironmentalImpactCategoryEnum::FromString(*data_->getArgument(7)); }
 void Ifc2x3::IfcEnvironmentalImpactValue::setCategory(::Ifc2x3::IfcEnvironmentalImpactCategoryEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcEnvironmentalImpactCategoryEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc2x3::IfcEnvironmentalImpactValue::UserDefinedCategory() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcEnvironmentalImpactValue::setUserDefinedCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcEnvironmentalImpactValue::setUserDefinedCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcEnvironmentalImpactValue::declaration() const { return *IFC2X3_IfcEnvironmentalImpactValue_type; }
@@ -11507,7 +11507,7 @@ Ifc2x3::IfcEvaporatorType::IfcEvaporatorType(std::string v1_GlobalId, ::Ifc2x3::
 aggregate_of< ::Ifc2x3::IfcProperty >::ptr Ifc2x3::IfcExtendedMaterialProperties::ExtendedProperties() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc2x3::IfcProperty >(); }
 void Ifc2x3::IfcExtendedMaterialProperties::setExtendedProperties(aggregate_of< ::Ifc2x3::IfcProperty >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcExtendedMaterialProperties::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcExtendedMaterialProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcExtendedMaterialProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::string Ifc2x3::IfcExtendedMaterialProperties::Name() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc2x3::IfcExtendedMaterialProperties::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -11519,11 +11519,11 @@ Ifc2x3::IfcExtendedMaterialProperties::IfcExtendedMaterialProperties(::Ifc2x3::I
 
 // Function implementations for IfcExternalReference
 boost::optional< std::string > Ifc2x3::IfcExternalReference::Location() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcExternalReference::ItemReference() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcExternalReference::setItemReference(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcExternalReference::setItemReference(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcExternalReference::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcExternalReference::declaration() const { return *IFC2X3_IfcExternalReference_type; }
@@ -11647,17 +11647,17 @@ Ifc2x3::IfcFacetedBrepWithVoids::IfcFacetedBrepWithVoids(::Ifc2x3::IfcClosedShel
 
 // Function implementations for IfcFailureConnectionCondition
 boost::optional< double > Ifc2x3::IfcFailureConnectionCondition::TensionFailureX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcFailureConnectionCondition::TensionFailureY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcFailureConnectionCondition::TensionFailureZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcFailureConnectionCondition::CompressionFailureX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcFailureConnectionCondition::CompressionFailureY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcFailureConnectionCondition::CompressionFailureZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcFailureConnectionCondition::declaration() const { return *IFC2X3_IfcFailureConnectionCondition_type; }
@@ -11935,11 +11935,11 @@ void Ifc2x3::IfcFluidFlowProperties::setFluid(::Ifc2x3::IfcMaterial* v) { {IfcWr
 ::Ifc2x3::IfcTimeSeries* Ifc2x3::IfcFluidFlowProperties::PressureTimeSeries() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc2x3::IfcTimeSeries>(true); }
 void Ifc2x3::IfcFluidFlowProperties::setPressureTimeSeries(::Ifc2x3::IfcTimeSeries* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc2x3::IfcFluidFlowProperties::UserDefinedPropertySource() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcFluidFlowProperties::setUserDefinedPropertySource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcFluidFlowProperties::setUserDefinedPropertySource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcFluidFlowProperties::TemperatureSingleValue() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcFluidFlowProperties::setTemperatureSingleValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcFluidFlowProperties::setTemperatureSingleValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc2x3::IfcFluidFlowProperties::WetBulbTemperatureSingleValue() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc2x3::IfcFluidFlowProperties::setWetBulbTemperatureSingleValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc2x3::IfcFluidFlowProperties::setWetBulbTemperatureSingleValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc2x3::IfcTimeSeries* Ifc2x3::IfcFluidFlowProperties::WetBulbTemperatureTimeSeries() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc2x3::IfcTimeSeries>(true); }
 void Ifc2x3::IfcFluidFlowProperties::setWetBulbTemperatureTimeSeries(::Ifc2x3::IfcTimeSeries* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 ::Ifc2x3::IfcTimeSeries* Ifc2x3::IfcFluidFlowProperties::TemperatureTimeSeries() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(14)))->as<::Ifc2x3::IfcTimeSeries>(true); }
@@ -11947,11 +11947,11 @@ void Ifc2x3::IfcFluidFlowProperties::setTemperatureTimeSeries(::Ifc2x3::IfcTimeS
 ::Ifc2x3::IfcDerivedMeasureValue* Ifc2x3::IfcFluidFlowProperties::FlowrateSingleValue() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(15)))->as<::Ifc2x3::IfcDerivedMeasureValue>(true); }
 void Ifc2x3::IfcFluidFlowProperties::setFlowrateSingleValue(::Ifc2x3::IfcDerivedMeasureValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(15,attr);} }
 boost::optional< double > Ifc2x3::IfcFluidFlowProperties::FlowConditionSingleValue() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc2x3::IfcFluidFlowProperties::setFlowConditionSingleValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc2x3::IfcFluidFlowProperties::setFlowConditionSingleValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc2x3::IfcFluidFlowProperties::VelocitySingleValue() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc2x3::IfcFluidFlowProperties::setVelocitySingleValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc2x3::IfcFluidFlowProperties::setVelocitySingleValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< double > Ifc2x3::IfcFluidFlowProperties::PressureSingleValue() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } double v = *data_->getArgument(18); return v; }
-void Ifc2x3::IfcFluidFlowProperties::setPressureSingleValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc2x3::IfcFluidFlowProperties::setPressureSingleValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcFluidFlowProperties::declaration() const { return *IFC2X3_IfcFluidFlowProperties_type; }
@@ -11971,13 +11971,13 @@ Ifc2x3::IfcFooting::IfcFooting(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistor
 
 // Function implementations for IfcFuelProperties
 boost::optional< double > Ifc2x3::IfcFuelProperties::CombustionTemperature() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcFuelProperties::setCombustionTemperature(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcFuelProperties::setCombustionTemperature(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcFuelProperties::CarbonContent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcFuelProperties::setCarbonContent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcFuelProperties::setCarbonContent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcFuelProperties::LowerHeatingValue() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcFuelProperties::setLowerHeatingValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcFuelProperties::setLowerHeatingValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcFuelProperties::HigherHeatingValue() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcFuelProperties::setHigherHeatingValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcFuelProperties::setHigherHeatingValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcFuelProperties::declaration() const { return *IFC2X3_IfcFuelProperties_type; }
@@ -12031,11 +12031,11 @@ Ifc2x3::IfcGasTerminalType::IfcGasTerminalType(std::string v1_GlobalId, ::Ifc2x3
 
 // Function implementations for IfcGeneralMaterialProperties
 boost::optional< double > Ifc2x3::IfcGeneralMaterialProperties::MolecularWeight() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcGeneralMaterialProperties::setMolecularWeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcGeneralMaterialProperties::setMolecularWeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcGeneralMaterialProperties::Porosity() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcGeneralMaterialProperties::setPorosity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcGeneralMaterialProperties::setPorosity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcGeneralMaterialProperties::MassDensity() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcGeneralMaterialProperties::setMassDensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcGeneralMaterialProperties::setMassDensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcGeneralMaterialProperties::declaration() const { return *IFC2X3_IfcGeneralMaterialProperties_type; }
@@ -12045,15 +12045,15 @@ Ifc2x3::IfcGeneralMaterialProperties::IfcGeneralMaterialProperties(::Ifc2x3::Ifc
 
 // Function implementations for IfcGeneralProfileProperties
 boost::optional< double > Ifc2x3::IfcGeneralProfileProperties::PhysicalWeight() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcGeneralProfileProperties::setPhysicalWeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcGeneralProfileProperties::setPhysicalWeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcGeneralProfileProperties::Perimeter() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcGeneralProfileProperties::setPerimeter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcGeneralProfileProperties::setPerimeter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcGeneralProfileProperties::MinimumPlateThickness() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcGeneralProfileProperties::setMinimumPlateThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcGeneralProfileProperties::setMinimumPlateThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcGeneralProfileProperties::MaximumPlateThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcGeneralProfileProperties::setMaximumPlateThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcGeneralProfileProperties::setMaximumPlateThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcGeneralProfileProperties::CrossSectionArea() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcGeneralProfileProperties::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcGeneralProfileProperties::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcGeneralProfileProperties::declaration() const { return *IFC2X3_IfcGeneralProfileProperties_type; }
@@ -12073,7 +12073,7 @@ Ifc2x3::IfcGeometricCurveSet::IfcGeometricCurveSet(aggregate_of_instance::ptr v1
 int Ifc2x3::IfcGeometricRepresentationContext::CoordinateSpaceDimension() const {  int v = *data_->getArgument(2); return v; }
 void Ifc2x3::IfcGeometricRepresentationContext::setCoordinateSpaceDimension(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcGeometricRepresentationContext::Precision() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc2x3::IfcAxis2Placement* Ifc2x3::IfcGeometricRepresentationContext::WorldCoordinateSystem() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc2x3::IfcAxis2Placement>(true); }
 void Ifc2x3::IfcGeometricRepresentationContext::setWorldCoordinateSystem(::Ifc2x3::IfcAxis2Placement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 ::Ifc2x3::IfcDirection* Ifc2x3::IfcGeometricRepresentationContext::TrueNorth() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc2x3::IfcDirection>(true); }
@@ -12098,11 +12098,11 @@ Ifc2x3::IfcGeometricRepresentationItem::IfcGeometricRepresentationItem() : IfcRe
 ::Ifc2x3::IfcGeometricRepresentationContext* Ifc2x3::IfcGeometricRepresentationSubContext::ParentContext() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc2x3::IfcGeometricRepresentationContext>(true); }
 void Ifc2x3::IfcGeometricRepresentationSubContext::setParentContext(::Ifc2x3::IfcGeometricRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcGeometricRepresentationSubContext::TargetScale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc2x3::IfcGeometricProjectionEnum::Value Ifc2x3::IfcGeometricRepresentationSubContext::TargetView() const {  return ::Ifc2x3::IfcGeometricProjectionEnum::FromString(*data_->getArgument(8)); }
 void Ifc2x3::IfcGeometricRepresentationSubContext::setTargetView(::Ifc2x3::IfcGeometricProjectionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcGeometricProjectionEnum::ToString(v)));data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc2x3::IfcGeometricRepresentationSubContext::UserDefinedTargetView() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcGeometricRepresentationSubContext::declaration() const { return *IFC2X3_IfcGeometricRepresentationSubContext_type; }
@@ -12126,7 +12126,7 @@ void Ifc2x3::IfcGrid::setUAxes(aggregate_of< ::Ifc2x3::IfcGridAxis >::ptr v) { {
 aggregate_of< ::Ifc2x3::IfcGridAxis >::ptr Ifc2x3::IfcGrid::VAxes() const {  aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc2x3::IfcGridAxis >(); }
 void Ifc2x3::IfcGrid::setVAxes(aggregate_of< ::Ifc2x3::IfcGridAxis >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcGridAxis >::ptr > Ifc2x3::IfcGrid::WAxes() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc2x3::IfcGridAxis >(); }
-void Ifc2x3::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc2x3::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc2x3::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc2x3::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 
 ::Ifc2x3::IfcRelContainedInSpatialStructure::list::ptr Ifc2x3::IfcGrid::ContainedInStructure() const { return data_->getInverse(IFC2X3_IfcRelContainedInSpatialStructure_type, 4)->as<IfcRelContainedInSpatialStructure>(); }
 
@@ -12137,7 +12137,7 @@ Ifc2x3::IfcGrid::IfcGrid(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory* v2_
 
 // Function implementations for IfcGridAxis
 boost::optional< std::string > Ifc2x3::IfcGridAxis::AxisTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc2x3::IfcCurve* Ifc2x3::IfcGridAxis::AxisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc2x3::IfcCurve>(true); }
 void Ifc2x3::IfcGridAxis::setAxisCurve(::Ifc2x3::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 bool Ifc2x3::IfcGridAxis::SameSense() const {  bool v = *data_->getArgument(2); return v; }
@@ -12208,15 +12208,15 @@ Ifc2x3::IfcHumidifierType::IfcHumidifierType(std::string v1_GlobalId, ::Ifc2x3::
 
 // Function implementations for IfcHygroscopicMaterialProperties
 boost::optional< double > Ifc2x3::IfcHygroscopicMaterialProperties::UpperVaporResistanceFactor() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcHygroscopicMaterialProperties::setUpperVaporResistanceFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcHygroscopicMaterialProperties::setUpperVaporResistanceFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcHygroscopicMaterialProperties::LowerVaporResistanceFactor() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcHygroscopicMaterialProperties::setLowerVaporResistanceFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcHygroscopicMaterialProperties::setLowerVaporResistanceFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcHygroscopicMaterialProperties::IsothermalMoistureCapacity() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcHygroscopicMaterialProperties::setIsothermalMoistureCapacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcHygroscopicMaterialProperties::setIsothermalMoistureCapacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcHygroscopicMaterialProperties::VaporPermeability() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcHygroscopicMaterialProperties::setVaporPermeability(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcHygroscopicMaterialProperties::setVaporPermeability(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcHygroscopicMaterialProperties::MoistureDiffusivity() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcHygroscopicMaterialProperties::setMoistureDiffusivity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcHygroscopicMaterialProperties::setMoistureDiffusivity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcHygroscopicMaterialProperties::declaration() const { return *IFC2X3_IfcHygroscopicMaterialProperties_type; }
@@ -12234,7 +12234,7 @@ void Ifc2x3::IfcIShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc2x3::IfcIShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc2x3::IfcIShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcIShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcIShapeProfileDef::declaration() const { return *IFC2X3_IfcIShapeProfileDef_type; }
@@ -12308,19 +12308,19 @@ Ifc2x3::IfcJunctionBoxType::IfcJunctionBoxType(std::string v1_GlobalId, ::Ifc2x3
 double Ifc2x3::IfcLShapeProfileDef::Depth() const {  double v = *data_->getArgument(3); return v; }
 void Ifc2x3::IfcLShapeProfileDef::setDepth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcLShapeProfileDef::Width() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 double Ifc2x3::IfcLShapeProfileDef::Thickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc2x3::IfcLShapeProfileDef::setThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcLShapeProfileDef::FilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcLShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcLShapeProfileDef::LegSlope() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcLShapeProfileDef::CentreOfGravityInX() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcLShapeProfileDef::setCentreOfGravityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcLShapeProfileDef::setCentreOfGravityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcLShapeProfileDef::CentreOfGravityInY() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcLShapeProfileDef::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcLShapeProfileDef::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcLShapeProfileDef::declaration() const { return *IFC2X3_IfcLShapeProfileDef_type; }
@@ -12330,7 +12330,7 @@ Ifc2x3::IfcLShapeProfileDef::IfcLShapeProfileDef(::Ifc2x3::IfcProfileTypeEnum::V
 
 // Function implementations for IfcLaborResource
 boost::optional< std::string > Ifc2x3::IfcLaborResource::SkillSet() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcLaborResource::setSkillSet(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcLaborResource::setSkillSet(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcLaborResource::declaration() const { return *IFC2X3_IfcLaborResource_type; }
@@ -12352,13 +12352,13 @@ Ifc2x3::IfcLampType::IfcLampType(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHist
 std::string Ifc2x3::IfcLibraryInformation::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc2x3::IfcLibraryInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcLibraryInformation::Version() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc2x3::IfcOrganization* Ifc2x3::IfcLibraryInformation::Publisher() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc2x3::IfcOrganization>(true); }
 void Ifc2x3::IfcLibraryInformation::setPublisher(::Ifc2x3::IfcOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcCalendarDate* Ifc2x3::IfcLibraryInformation::VersionDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc2x3::IfcCalendarDate>(true); }
 void Ifc2x3::IfcLibraryInformation::setVersionDate(::Ifc2x3::IfcCalendarDate* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcLibraryReference >::ptr > Ifc2x3::IfcLibraryInformation::LibraryReference() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc2x3::IfcLibraryReference >(); }
-void Ifc2x3::IfcLibraryInformation::setLibraryReference(boost::optional< aggregate_of< ::Ifc2x3::IfcLibraryReference >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(4,attr);} }
+void Ifc2x3::IfcLibraryInformation::setLibraryReference(boost::optional< aggregate_of< ::Ifc2x3::IfcLibraryReference >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcLibraryInformation::declaration() const { return *IFC2X3_IfcLibraryInformation_type; }
@@ -12413,13 +12413,13 @@ Ifc2x3::IfcLightIntensityDistribution::IfcLightIntensityDistribution(::Ifc2x3::I
 
 // Function implementations for IfcLightSource
 boost::optional< std::string > Ifc2x3::IfcLightSource::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc2x3::IfcColourRgb* Ifc2x3::IfcLightSource::LightColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc2x3::IfcColourRgb>(true); }
 void Ifc2x3::IfcLightSource::setLightColour(::Ifc2x3::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcLightSource::AmbientIntensity() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcLightSource::Intensity() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcLightSource::declaration() const { return *IFC2X3_IfcLightSource_type; }
@@ -12487,7 +12487,7 @@ Ifc2x3::IfcLightSourcePositional::IfcLightSourcePositional(boost::optional< std:
 ::Ifc2x3::IfcDirection* Ifc2x3::IfcLightSourceSpot::Orientation() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc2x3::IfcDirection>(true); }
 void Ifc2x3::IfcLightSourceSpot::setOrientation(::Ifc2x3::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcLightSourceSpot::ConcentrationExponent() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 double Ifc2x3::IfcLightSourceSpot::SpreadAngle() const {  double v = *data_->getArgument(11); return v; }
 void Ifc2x3::IfcLightSourceSpot::setSpreadAngle(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 double Ifc2x3::IfcLightSourceSpot::BeamWidthAngle() const {  double v = *data_->getArgument(12); return v; }
@@ -12535,13 +12535,13 @@ Ifc2x3::IfcLocalPlacement::IfcLocalPlacement(::Ifc2x3::IfcObjectPlacement* v1_Pl
 int Ifc2x3::IfcLocalTime::HourComponent() const {  int v = *data_->getArgument(0); return v; }
 void Ifc2x3::IfcLocalTime::setHourComponent(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< int > Ifc2x3::IfcLocalTime::MinuteComponent() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } int v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcLocalTime::setMinuteComponent(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcLocalTime::setMinuteComponent(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcLocalTime::SecondComponent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcLocalTime::setSecondComponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcLocalTime::setSecondComponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcCoordinatedUniversalTimeOffset* Ifc2x3::IfcLocalTime::Zone() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc2x3::IfcCoordinatedUniversalTimeOffset>(true); }
 void Ifc2x3::IfcLocalTime::setZone(::Ifc2x3::IfcCoordinatedUniversalTimeOffset* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc2x3::IfcLocalTime::DaylightSavingOffset() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcLocalTime::setDaylightSavingOffset(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcLocalTime::setDaylightSavingOffset(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcLocalTime::declaration() const { return *IFC2X3_IfcLocalTime_type; }
@@ -12619,7 +12619,7 @@ void Ifc2x3::IfcMaterialLayer::setMaterial(::Ifc2x3::IfcMaterial* v) { {IfcWrite
 double Ifc2x3::IfcMaterialLayer::LayerThickness() const {  double v = *data_->getArgument(1); return v; }
 void Ifc2x3::IfcMaterialLayer::setLayerThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< boost::logic::tribool > Ifc2x3::IfcMaterialLayer::IsVentilated() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } boost::logic::tribool v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc2x3::IfcMaterialLayerSet::list::ptr Ifc2x3::IfcMaterialLayer::ToMaterialLayerSet() const { return data_->getInverse(IFC2X3_IfcMaterialLayerSet_type, 0)->as<IfcMaterialLayerSet>(); }
 
@@ -12632,7 +12632,7 @@ Ifc2x3::IfcMaterialLayer::IfcMaterialLayer(::Ifc2x3::IfcMaterial* v1_Material, d
 aggregate_of< ::Ifc2x3::IfcMaterialLayer >::ptr Ifc2x3::IfcMaterialLayerSet::MaterialLayers() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc2x3::IfcMaterialLayer >(); }
 void Ifc2x3::IfcMaterialLayerSet::setMaterialLayers(aggregate_of< ::Ifc2x3::IfcMaterialLayer >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcMaterialLayerSet::LayerSetName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcMaterialLayerSet::declaration() const { return *IFC2X3_IfcMaterialLayerSet_type; }
@@ -12690,17 +12690,17 @@ Ifc2x3::IfcMeasureWithUnit::IfcMeasureWithUnit(::Ifc2x3::IfcValue* v1_ValueCompo
 
 // Function implementations for IfcMechanicalConcreteMaterialProperties
 boost::optional< double > Ifc2x3::IfcMechanicalConcreteMaterialProperties::CompressiveStrength() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setCompressiveStrength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setCompressiveStrength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalConcreteMaterialProperties::MaxAggregateSize() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setMaxAggregateSize(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setMaxAggregateSize(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc2x3::IfcMechanicalConcreteMaterialProperties::AdmixturesDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setAdmixturesDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setAdmixturesDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc2x3::IfcMechanicalConcreteMaterialProperties::Workability() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setWorkability(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setWorkability(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalConcreteMaterialProperties::ProtectivePoreRatio() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setProtectivePoreRatio(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setProtectivePoreRatio(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc2x3::IfcMechanicalConcreteMaterialProperties::WaterImpermeability() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setWaterImpermeability(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcMechanicalConcreteMaterialProperties::setWaterImpermeability(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcMechanicalConcreteMaterialProperties::declaration() const { return *IFC2X3_IfcMechanicalConcreteMaterialProperties_type; }
@@ -12710,9 +12710,9 @@ Ifc2x3::IfcMechanicalConcreteMaterialProperties::IfcMechanicalConcreteMaterialPr
 
 // Function implementations for IfcMechanicalFastener
 boost::optional< double > Ifc2x3::IfcMechanicalFastener::NominalDiameter() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalFastener::NominalLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcMechanicalFastener::declaration() const { return *IFC2X3_IfcMechanicalFastener_type; }
@@ -12730,15 +12730,15 @@ Ifc2x3::IfcMechanicalFastenerType::IfcMechanicalFastenerType(std::string v1_Glob
 
 // Function implementations for IfcMechanicalMaterialProperties
 boost::optional< double > Ifc2x3::IfcMechanicalMaterialProperties::DynamicViscosity() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcMechanicalMaterialProperties::setDynamicViscosity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcMechanicalMaterialProperties::setDynamicViscosity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalMaterialProperties::YoungModulus() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcMechanicalMaterialProperties::setYoungModulus(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcMechanicalMaterialProperties::setYoungModulus(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalMaterialProperties::ShearModulus() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcMechanicalMaterialProperties::setShearModulus(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcMechanicalMaterialProperties::setShearModulus(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalMaterialProperties::PoissonRatio() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcMechanicalMaterialProperties::setPoissonRatio(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcMechanicalMaterialProperties::setPoissonRatio(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalMaterialProperties::ThermalExpansionCoefficient() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcMechanicalMaterialProperties::setThermalExpansionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcMechanicalMaterialProperties::setThermalExpansionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcMechanicalMaterialProperties::declaration() const { return *IFC2X3_IfcMechanicalMaterialProperties_type; }
@@ -12748,19 +12748,19 @@ Ifc2x3::IfcMechanicalMaterialProperties::IfcMechanicalMaterialProperties(::Ifc2x
 
 // Function implementations for IfcMechanicalSteelMaterialProperties
 boost::optional< double > Ifc2x3::IfcMechanicalSteelMaterialProperties::YieldStress() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcMechanicalSteelMaterialProperties::setYieldStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcMechanicalSteelMaterialProperties::setYieldStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalSteelMaterialProperties::UltimateStress() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcMechanicalSteelMaterialProperties::setUltimateStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcMechanicalSteelMaterialProperties::setUltimateStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalSteelMaterialProperties::UltimateStrain() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcMechanicalSteelMaterialProperties::setUltimateStrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcMechanicalSteelMaterialProperties::setUltimateStrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalSteelMaterialProperties::HardeningModule() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcMechanicalSteelMaterialProperties::setHardeningModule(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcMechanicalSteelMaterialProperties::setHardeningModule(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalSteelMaterialProperties::ProportionalStress() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcMechanicalSteelMaterialProperties::setProportionalStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcMechanicalSteelMaterialProperties::setProportionalStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcMechanicalSteelMaterialProperties::PlasticStrain() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcMechanicalSteelMaterialProperties::setPlasticStrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcMechanicalSteelMaterialProperties::setPlasticStrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcRelaxation >::ptr > Ifc2x3::IfcMechanicalSteelMaterialProperties::Relaxations() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(12); return es->as< ::Ifc2x3::IfcRelaxation >(); }
-void Ifc2x3::IfcMechanicalSteelMaterialProperties::setRelaxations(boost::optional< aggregate_of< ::Ifc2x3::IfcRelaxation >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(12,attr);} }
+void Ifc2x3::IfcMechanicalSteelMaterialProperties::setRelaxations(boost::optional< aggregate_of< ::Ifc2x3::IfcRelaxation >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcMechanicalSteelMaterialProperties::declaration() const { return *IFC2X3_IfcMechanicalSteelMaterialProperties_type; }
@@ -12790,7 +12790,7 @@ Ifc2x3::IfcMemberType::IfcMemberType(std::string v1_GlobalId, ::Ifc2x3::IfcOwner
 ::Ifc2x3::IfcBenchmarkEnum::Value Ifc2x3::IfcMetric::Benchmark() const {  return ::Ifc2x3::IfcBenchmarkEnum::FromString(*data_->getArgument(7)); }
 void Ifc2x3::IfcMetric::setBenchmark(::Ifc2x3::IfcBenchmarkEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcBenchmarkEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc2x3::IfcMetric::ValueSource() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc2x3::IfcMetricValueSelect* Ifc2x3::IfcMetric::DataValue() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc2x3::IfcMetricValueSelect>(true); }
 void Ifc2x3::IfcMetric::setDataValue(::Ifc2x3::IfcMetricValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -12826,7 +12826,7 @@ void Ifc2x3::IfcMove::setMoveFrom(::Ifc2x3::IfcSpatialStructureElement* v) { {If
 ::Ifc2x3::IfcSpatialStructureElement* Ifc2x3::IfcMove::MoveTo() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc2x3::IfcSpatialStructureElement>(true); }
 void Ifc2x3::IfcMove::setMoveTo(::Ifc2x3::IfcSpatialStructureElement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc2x3::IfcMove::PunchList() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(12); return v; }
-void Ifc2x3::IfcMove::setPunchList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc2x3::IfcMove::setPunchList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcMove::declaration() const { return *IFC2X3_IfcMove_type; }
@@ -12848,7 +12848,7 @@ Ifc2x3::IfcNamedUnit::IfcNamedUnit(::Ifc2x3::IfcDimensionalExponents* v1_Dimensi
 
 // Function implementations for IfcObject
 boost::optional< std::string > Ifc2x3::IfcObject::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc2x3::IfcRelDefines::list::ptr Ifc2x3::IfcObject::IsDefinedBy() const { return data_->getInverse(IFC2X3_IfcRelDefines_type, 4)->as<IfcRelDefines>(); }
 
@@ -12887,7 +12887,7 @@ void Ifc2x3::IfcObjective::setResultValues(::Ifc2x3::IfcMetric* v) { {IfcWrite::
 ::Ifc2x3::IfcObjectiveEnum::Value Ifc2x3::IfcObjective::ObjectiveQualifier() const {  return ::Ifc2x3::IfcObjectiveEnum::FromString(*data_->getArgument(9)); }
 void Ifc2x3::IfcObjective::setObjectiveQualifier(::Ifc2x3::IfcObjectiveEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcObjectiveEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc2x3::IfcObjective::UserDefinedQualifier() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcObjective::declaration() const { return *IFC2X3_IfcObjective_type; }
@@ -12964,23 +12964,23 @@ Ifc2x3::IfcOpeningElement::IfcOpeningElement(std::string v1_GlobalId, ::Ifc2x3::
 
 // Function implementations for IfcOpticalMaterialProperties
 boost::optional< double > Ifc2x3::IfcOpticalMaterialProperties::VisibleTransmittance() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcOpticalMaterialProperties::setVisibleTransmittance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcOpticalMaterialProperties::setVisibleTransmittance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcOpticalMaterialProperties::SolarTransmittance() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcOpticalMaterialProperties::setSolarTransmittance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcOpticalMaterialProperties::setSolarTransmittance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcOpticalMaterialProperties::ThermalIrTransmittance() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcOpticalMaterialProperties::setThermalIrTransmittance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcOpticalMaterialProperties::setThermalIrTransmittance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcOpticalMaterialProperties::ThermalIrEmissivityBack() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcOpticalMaterialProperties::setThermalIrEmissivityBack(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcOpticalMaterialProperties::setThermalIrEmissivityBack(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcOpticalMaterialProperties::ThermalIrEmissivityFront() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcOpticalMaterialProperties::setThermalIrEmissivityFront(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcOpticalMaterialProperties::setThermalIrEmissivityFront(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcOpticalMaterialProperties::VisibleReflectanceBack() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcOpticalMaterialProperties::setVisibleReflectanceBack(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcOpticalMaterialProperties::setVisibleReflectanceBack(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcOpticalMaterialProperties::VisibleReflectanceFront() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcOpticalMaterialProperties::setVisibleReflectanceFront(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcOpticalMaterialProperties::setVisibleReflectanceFront(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcOpticalMaterialProperties::SolarReflectanceFront() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcOpticalMaterialProperties::setSolarReflectanceFront(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcOpticalMaterialProperties::setSolarReflectanceFront(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcOpticalMaterialProperties::SolarReflectanceBack() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcOpticalMaterialProperties::setSolarReflectanceBack(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcOpticalMaterialProperties::setSolarReflectanceBack(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcOpticalMaterialProperties::declaration() const { return *IFC2X3_IfcOpticalMaterialProperties_type; }
@@ -13000,15 +13000,15 @@ Ifc2x3::IfcOrderAction::IfcOrderAction(std::string v1_GlobalId, ::Ifc2x3::IfcOwn
 
 // Function implementations for IfcOrganization
 boost::optional< std::string > Ifc2x3::IfcOrganization::Id() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcOrganization::setId(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcOrganization::setId(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 std::string Ifc2x3::IfcOrganization::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc2x3::IfcOrganization::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcOrganization::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcActorRole >::ptr > Ifc2x3::IfcOrganization::Roles() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc2x3::IfcActorRole >(); }
-void Ifc2x3::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc2x3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(3,attr);} }
+void Ifc2x3::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc2x3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(3,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcAddress >::ptr > Ifc2x3::IfcOrganization::Addresses() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc2x3::IfcAddress >(); }
-void Ifc2x3::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc2x3::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(4,attr);} }
+void Ifc2x3::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc2x3::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(4,attr);} }
 
 ::Ifc2x3::IfcOrganizationRelationship::list::ptr Ifc2x3::IfcOrganization::IsRelatedBy() const { return data_->getInverse(IFC2X3_IfcOrganizationRelationship_type, 3)->as<IfcOrganizationRelationship>(); }
 ::Ifc2x3::IfcOrganizationRelationship::list::ptr Ifc2x3::IfcOrganization::Relates() const { return data_->getInverse(IFC2X3_IfcOrganizationRelationship_type, 2)->as<IfcOrganizationRelationship>(); }
@@ -13023,7 +13023,7 @@ Ifc2x3::IfcOrganization::IfcOrganization(boost::optional< std::string > v1_Id, s
 std::string Ifc2x3::IfcOrganizationRelationship::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc2x3::IfcOrganizationRelationship::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcOrganizationRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcOrganizationRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcOrganizationRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc2x3::IfcOrganization* Ifc2x3::IfcOrganizationRelationship::RelatingOrganization() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc2x3::IfcOrganization>(true); }
 void Ifc2x3::IfcOrganizationRelationship::setRelatingOrganization(::Ifc2x3::IfcOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc2x3::IfcOrganization >::ptr Ifc2x3::IfcOrganizationRelationship::RelatedOrganizations() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc2x3::IfcOrganization >(); }
@@ -13063,11 +13063,11 @@ void Ifc2x3::IfcOwnerHistory::setOwningUser(::Ifc2x3::IfcPersonAndOrganization*
 ::Ifc2x3::IfcApplication* Ifc2x3::IfcOwnerHistory::OwningApplication() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc2x3::IfcApplication>(true); }
 void Ifc2x3::IfcOwnerHistory::setOwningApplication(::Ifc2x3::IfcApplication* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc2x3::IfcStateEnum::Value > Ifc2x3::IfcOwnerHistory::State() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc2x3::IfcStateEnum::FromString(*data_->getArgument(2)); }
-void Ifc2x3::IfcOwnerHistory::setState(boost::optional< ::Ifc2x3::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcStateEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc2x3::IfcOwnerHistory::setState(boost::optional< ::Ifc2x3::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcStateEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcChangeActionEnum::Value Ifc2x3::IfcOwnerHistory::ChangeAction() const {  return ::Ifc2x3::IfcChangeActionEnum::FromString(*data_->getArgument(3)); }
 void Ifc2x3::IfcOwnerHistory::setChangeAction(::Ifc2x3::IfcChangeActionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcChangeActionEnum::ToString(v)));data_->setArgument(3,attr);} }
 boost::optional< int > Ifc2x3::IfcOwnerHistory::LastModifiedDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc2x3::IfcPersonAndOrganization* Ifc2x3::IfcOwnerHistory::LastModifyingUser() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc2x3::IfcPersonAndOrganization>(true); }
 void Ifc2x3::IfcOwnerHistory::setLastModifyingUser(::Ifc2x3::IfcPersonAndOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc2x3::IfcApplication* Ifc2x3::IfcOwnerHistory::LastModifyingApplication() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc2x3::IfcApplication>(true); }
@@ -13117,9 +13117,9 @@ void Ifc2x3::IfcPermeableCoveringProperties::setOperationType(::Ifc2x3::IfcPerme
 ::Ifc2x3::IfcWindowPanelPositionEnum::Value Ifc2x3::IfcPermeableCoveringProperties::PanelPosition() const {  return ::Ifc2x3::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc2x3::IfcPermeableCoveringProperties::setPanelPosition(::Ifc2x3::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcPermeableCoveringProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcPermeableCoveringProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc2x3::IfcShapeAspect* Ifc2x3::IfcPermeableCoveringProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc2x3::IfcShapeAspect>(true); }
 void Ifc2x3::IfcPermeableCoveringProperties::setShapeAspectStyle(::Ifc2x3::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -13141,21 +13141,21 @@ Ifc2x3::IfcPermit::IfcPermit(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory*
 
 // Function implementations for IfcPerson
 boost::optional< std::string > Ifc2x3::IfcPerson::Id() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcPerson::setId(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcPerson::setId(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPerson::FamilyName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPerson::GivenName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc2x3::IfcPerson::MiddleNames() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc2x3::IfcPerson::PrefixTitles() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc2x3::IfcPerson::SuffixTitles() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcActorRole >::ptr > Ifc2x3::IfcPerson::Roles() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc2x3::IfcActorRole >(); }
-void Ifc2x3::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc2x3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc2x3::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc2x3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcAddress >::ptr > Ifc2x3::IfcPerson::Addresses() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc2x3::IfcAddress >(); }
-void Ifc2x3::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc2x3::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc2x3::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc2x3::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 ::Ifc2x3::IfcPersonAndOrganization::list::ptr Ifc2x3::IfcPerson::EngagedIn() const { return data_->getInverse(IFC2X3_IfcPersonAndOrganization_type, 0)->as<IfcPersonAndOrganization>(); }
 
@@ -13170,7 +13170,7 @@ void Ifc2x3::IfcPersonAndOrganization::setThePerson(::Ifc2x3::IfcPerson* v) { {I
 ::Ifc2x3::IfcOrganization* Ifc2x3::IfcPersonAndOrganization::TheOrganization() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc2x3::IfcOrganization>(true); }
 void Ifc2x3::IfcPersonAndOrganization::setTheOrganization(::Ifc2x3::IfcOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcActorRole >::ptr > Ifc2x3::IfcPersonAndOrganization::Roles() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc2x3::IfcActorRole >(); }
-void Ifc2x3::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc2x3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc2x3::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc2x3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcPersonAndOrganization::declaration() const { return *IFC2X3_IfcPersonAndOrganization_type; }
@@ -13184,9 +13184,9 @@ void Ifc2x3::IfcPhysicalComplexQuantity::setHasQuantities(aggregate_of< ::Ifc2x3
 std::string Ifc2x3::IfcPhysicalComplexQuantity::Discrimination() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc2x3::IfcPhysicalComplexQuantity::setDiscrimination(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPhysicalComplexQuantity::Quality() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPhysicalComplexQuantity::Usage() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcPhysicalComplexQuantity::declaration() const { return *IFC2X3_IfcPhysicalComplexQuantity_type; }
@@ -13198,7 +13198,7 @@ Ifc2x3::IfcPhysicalComplexQuantity::IfcPhysicalComplexQuantity(std::string v1_Na
 std::string Ifc2x3::IfcPhysicalQuantity::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc2x3::IfcPhysicalQuantity::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPhysicalQuantity::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc2x3::IfcPhysicalComplexQuantity::list::ptr Ifc2x3::IfcPhysicalQuantity::PartOfComplex() const { return data_->getInverse(IFC2X3_IfcPhysicalComplexQuantity_type, 2)->as<IfcPhysicalComplexQuantity>(); }
 
@@ -13221,7 +13221,7 @@ Ifc2x3::IfcPhysicalSimpleQuantity::IfcPhysicalSimpleQuantity(std::string v1_Name
 ::Ifc2x3::IfcPileTypeEnum::Value Ifc2x3::IfcPile::PredefinedType() const {  return ::Ifc2x3::IfcPileTypeEnum::FromString(*data_->getArgument(8)); }
 void Ifc2x3::IfcPile::setPredefinedType(::Ifc2x3::IfcPileTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcPileTypeEnum::ToString(v)));data_->setArgument(8,attr);} }
 boost::optional< ::Ifc2x3::IfcPileConstructionEnum::Value > Ifc2x3::IfcPile::ConstructionType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc2x3::IfcPileConstructionEnum::FromString(*data_->getArgument(9)); }
-void Ifc2x3::IfcPile::setConstructionType(boost::optional< ::Ifc2x3::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcPileConstructionEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc2x3::IfcPile::setConstructionType(boost::optional< ::Ifc2x3::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcPileConstructionEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcPile::declaration() const { return *IFC2X3_IfcPile_type; }
@@ -13402,19 +13402,19 @@ Ifc2x3::IfcPort::IfcPort(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory* v2_
 
 // Function implementations for IfcPostalAddress
 boost::optional< std::string > Ifc2x3::IfcPostalAddress::InternalLocation() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc2x3::IfcPostalAddress::AddressLines() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPostalAddress::PostalBox() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPostalAddress::Town() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPostalAddress::Region() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPostalAddress::PostalCode() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPostalAddress::Country() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcPostalAddress::declaration() const { return *IFC2X3_IfcPostalAddress_type; }
@@ -13492,11 +13492,11 @@ Ifc2x3::IfcPreDefinedTextFont::IfcPreDefinedTextFont(std::string v1_Name) : IfcP
 std::string Ifc2x3::IfcPresentationLayerAssignment::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc2x3::IfcPresentationLayerAssignment::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPresentationLayerAssignment::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of_instance::ptr Ifc2x3::IfcPresentationLayerAssignment::AssignedItems() const {  aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
 void Ifc2x3::IfcPresentationLayerAssignment::setAssignedItems(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPresentationLayerAssignment::Identifier() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcPresentationLayerAssignment::declaration() const { return *IFC2X3_IfcPresentationLayerAssignment_type; }
@@ -13522,7 +13522,7 @@ Ifc2x3::IfcPresentationLayerWithStyle::IfcPresentationLayerWithStyle(std::string
 
 // Function implementations for IfcPresentationStyle
 boost::optional< std::string > Ifc2x3::IfcPresentationStyle::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcPresentationStyle::declaration() const { return *IFC2X3_IfcPresentationStyle_type; }
@@ -13546,7 +13546,7 @@ void Ifc2x3::IfcProcedure::setProcedureID(std::string v) { {IfcWrite::IfcWriteAr
 ::Ifc2x3::IfcProcedureTypeEnum::Value Ifc2x3::IfcProcedure::ProcedureType() const {  return ::Ifc2x3::IfcProcedureTypeEnum::FromString(*data_->getArgument(6)); }
 void Ifc2x3::IfcProcedure::setProcedureType(::Ifc2x3::IfcProcedureTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcProcedureTypeEnum::ToString(v)));data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc2x3::IfcProcedure::UserDefinedProcedureType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcProcedure::setUserDefinedProcedureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcProcedure::setUserDefinedProcedureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcProcedure::declaration() const { return *IFC2X3_IfcProcedure_type; }
@@ -13590,9 +13590,9 @@ Ifc2x3::IfcProductDefinitionShape::IfcProductDefinitionShape(boost::optional< st
 
 // Function implementations for IfcProductRepresentation
 boost::optional< std::string > Ifc2x3::IfcProductRepresentation::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcProductRepresentation::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc2x3::IfcRepresentation >::ptr Ifc2x3::IfcProductRepresentation::Representations() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc2x3::IfcRepresentation >(); }
 void Ifc2x3::IfcProductRepresentation::setRepresentations(aggregate_of< ::Ifc2x3::IfcRepresentation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -13604,13 +13604,13 @@ Ifc2x3::IfcProductRepresentation::IfcProductRepresentation(boost::optional< std:
 
 // Function implementations for IfcProductsOfCombustionProperties
 boost::optional< double > Ifc2x3::IfcProductsOfCombustionProperties::SpecificHeatCapacity() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcProductsOfCombustionProperties::setSpecificHeatCapacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcProductsOfCombustionProperties::setSpecificHeatCapacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcProductsOfCombustionProperties::N20Content() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcProductsOfCombustionProperties::setN20Content(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcProductsOfCombustionProperties::setN20Content(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcProductsOfCombustionProperties::COContent() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcProductsOfCombustionProperties::setCOContent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcProductsOfCombustionProperties::setCOContent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcProductsOfCombustionProperties::CO2Content() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcProductsOfCombustionProperties::setCO2Content(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcProductsOfCombustionProperties::setCO2Content(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcProductsOfCombustionProperties::declaration() const { return *IFC2X3_IfcProductsOfCombustionProperties_type; }
@@ -13622,7 +13622,7 @@ Ifc2x3::IfcProductsOfCombustionProperties::IfcProductsOfCombustionProperties(::I
 ::Ifc2x3::IfcProfileTypeEnum::Value Ifc2x3::IfcProfileDef::ProfileType() const {  return ::Ifc2x3::IfcProfileTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc2x3::IfcProfileDef::setProfileType(::Ifc2x3::IfcProfileTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcProfileTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcProfileDef::ProfileName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcProfileDef::declaration() const { return *IFC2X3_IfcProfileDef_type; }
@@ -13632,7 +13632,7 @@ Ifc2x3::IfcProfileDef::IfcProfileDef(::Ifc2x3::IfcProfileTypeEnum::Value v1_Prof
 
 // Function implementations for IfcProfileProperties
 boost::optional< std::string > Ifc2x3::IfcProfileProperties::ProfileName() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcProfileProperties::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcProfileProperties::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc2x3::IfcProfileDef* Ifc2x3::IfcProfileProperties::ProfileDefinition() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc2x3::IfcProfileDef>(true); }
 void Ifc2x3::IfcProfileProperties::setProfileDefinition(::Ifc2x3::IfcProfileDef* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 
@@ -13644,9 +13644,9 @@ Ifc2x3::IfcProfileProperties::IfcProfileProperties(boost::optional< std::string
 
 // Function implementations for IfcProject
 boost::optional< std::string > Ifc2x3::IfcProject::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcProject::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcProject::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc2x3::IfcProject::Phase() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcProject::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcProject::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 aggregate_of< ::Ifc2x3::IfcRepresentationContext >::ptr Ifc2x3::IfcProject::RepresentationContexts() const {  aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc2x3::IfcRepresentationContext >(); }
 void Ifc2x3::IfcProject::setRepresentationContexts(aggregate_of< ::Ifc2x3::IfcRepresentationContext >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(7,attr);} }
 ::Ifc2x3::IfcUnitAssignment* Ifc2x3::IfcProject::UnitsInContext() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc2x3::IfcUnitAssignment>(true); }
@@ -13664,7 +13664,7 @@ void Ifc2x3::IfcProjectOrder::setID(std::string v) { {IfcWrite::IfcWriteArgument
 ::Ifc2x3::IfcProjectOrderTypeEnum::Value Ifc2x3::IfcProjectOrder::PredefinedType() const {  return ::Ifc2x3::IfcProjectOrderTypeEnum::FromString(*data_->getArgument(6)); }
 void Ifc2x3::IfcProjectOrder::setPredefinedType(::Ifc2x3::IfcProjectOrderTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcProjectOrderTypeEnum::ToString(v)));data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc2x3::IfcProjectOrder::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcProjectOrder::declaration() const { return *IFC2X3_IfcProjectOrder_type; }
@@ -13704,7 +13704,7 @@ Ifc2x3::IfcProjectionElement::IfcProjectionElement(std::string v1_GlobalId, ::If
 std::string Ifc2x3::IfcProperty::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc2x3::IfcProperty::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcProperty::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc2x3::IfcPropertyDependencyRelationship::list::ptr Ifc2x3::IfcProperty::PropertyForDependance() const { return data_->getInverse(IFC2X3_IfcPropertyDependencyRelationship_type, 0)->as<IfcPropertyDependencyRelationship>(); }
 ::Ifc2x3::IfcPropertyDependencyRelationship::list::ptr Ifc2x3::IfcProperty::PropertyDependsOn() const { return data_->getInverse(IFC2X3_IfcPropertyDependencyRelationship_type, 1)->as<IfcPropertyDependencyRelationship>(); }
@@ -13735,9 +13735,9 @@ void Ifc2x3::IfcPropertyConstraintRelationship::setRelatingConstraint(::Ifc2x3::
 aggregate_of< ::Ifc2x3::IfcProperty >::ptr Ifc2x3::IfcPropertyConstraintRelationship::RelatedProperties() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc2x3::IfcProperty >(); }
 void Ifc2x3::IfcPropertyConstraintRelationship::setRelatedProperties(aggregate_of< ::Ifc2x3::IfcProperty >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPropertyConstraintRelationship::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcPropertyConstraintRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcPropertyConstraintRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPropertyConstraintRelationship::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcPropertyConstraintRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcPropertyConstraintRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcPropertyConstraintRelationship::declaration() const { return *IFC2X3_IfcPropertyConstraintRelationship_type; }
@@ -13760,11 +13760,11 @@ void Ifc2x3::IfcPropertyDependencyRelationship::setDependingProperty(::Ifc2x3::I
 ::Ifc2x3::IfcProperty* Ifc2x3::IfcPropertyDependencyRelationship::DependantProperty() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc2x3::IfcProperty>(true); }
 void Ifc2x3::IfcPropertyDependencyRelationship::setDependantProperty(::Ifc2x3::IfcProperty* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPropertyDependencyRelationship::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcPropertyDependencyRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcPropertyDependencyRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPropertyDependencyRelationship::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcPropertyDependencyRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcPropertyDependencyRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPropertyDependencyRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcPropertyDependencyRelationship::declaration() const { return *IFC2X3_IfcPropertyDependencyRelationship_type; }
@@ -13812,7 +13812,7 @@ Ifc2x3::IfcPropertyListValue::IfcPropertyListValue(std::string v1_Name, boost::o
 
 // Function implementations for IfcPropertyReferenceValue
 boost::optional< std::string > Ifc2x3::IfcPropertyReferenceValue::UsageName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcObjectReferenceSelect* Ifc2x3::IfcPropertyReferenceValue::PropertyReference() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc2x3::IfcObjectReferenceSelect>(true); }
 void Ifc2x3::IfcPropertyReferenceValue::setPropertyReference(::Ifc2x3::IfcObjectReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -13860,7 +13860,7 @@ void Ifc2x3::IfcPropertyTableValue::setDefiningValues(aggregate_of_instance::ptr
 aggregate_of_instance::ptr Ifc2x3::IfcPropertyTableValue::DefinedValues() const {  aggregate_of_instance::ptr v = *data_->getArgument(3); return v; }
 void Ifc2x3::IfcPropertyTableValue::setDefinedValues(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc2x3::IfcPropertyTableValue::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc2x3::IfcUnit* Ifc2x3::IfcPropertyTableValue::DefiningUnit() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc2x3::IfcUnit>(true); }
 void Ifc2x3::IfcPropertyTableValue::setDefiningUnit(::Ifc2x3::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc2x3::IfcUnit* Ifc2x3::IfcPropertyTableValue::DefinedUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc2x3::IfcUnit>(true); }
@@ -13886,7 +13886,7 @@ Ifc2x3::IfcProtectiveDeviceType::IfcProtectiveDeviceType(std::string v1_GlobalId
 ::Ifc2x3::IfcObjectTypeEnum::Value Ifc2x3::IfcProxy::ProxyType() const {  return ::Ifc2x3::IfcObjectTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc2x3::IfcProxy::setProxyType(::Ifc2x3::IfcObjectTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcObjectTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc2x3::IfcProxy::Tag() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcProxy::declaration() const { return *IFC2X3_IfcProxy_type; }
@@ -13974,7 +13974,7 @@ Ifc2x3::IfcRadiusDimension::IfcRadiusDimension(aggregate_of_instance::ptr v1_Con
 
 // Function implementations for IfcRailing
 boost::optional< ::Ifc2x3::IfcRailingTypeEnum::Value > Ifc2x3::IfcRailing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc2x3::IfcRailingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc2x3::IfcRailing::setPredefinedType(boost::optional< ::Ifc2x3::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcRailingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc2x3::IfcRailing::setPredefinedType(boost::optional< ::Ifc2x3::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcRailingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcRailing::declaration() const { return *IFC2X3_IfcRailing_type; }
@@ -14034,9 +14034,9 @@ Ifc2x3::IfcRationalBezierCurve::IfcRationalBezierCurve(int v1_Degree, aggregate_
 double Ifc2x3::IfcRectangleHollowProfileDef::WallThickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc2x3::IfcRectangleHollowProfileDef::setWallThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcRectangleHollowProfileDef::InnerFilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcRectangleHollowProfileDef::OuterFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcRectangleHollowProfileDef::declaration() const { return *IFC2X3_IfcRectangleHollowProfileDef_type; }
@@ -14098,9 +14098,9 @@ void Ifc2x3::IfcReferencesValueDocument::setReferencedDocument(::Ifc2x3::IfcDocu
 aggregate_of< ::Ifc2x3::IfcAppliedValue >::ptr Ifc2x3::IfcReferencesValueDocument::ReferencingValues() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc2x3::IfcAppliedValue >(); }
 void Ifc2x3::IfcReferencesValueDocument::setReferencingValues(aggregate_of< ::Ifc2x3::IfcAppliedValue >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcReferencesValueDocument::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcReferencesValueDocument::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcReferencesValueDocument::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc2x3::IfcReferencesValueDocument::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcReferencesValueDocument::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcReferencesValueDocument::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcReferencesValueDocument::declaration() const { return *IFC2X3_IfcReferencesValueDocument_type; }
@@ -14126,13 +14126,13 @@ void Ifc2x3::IfcReinforcementBarProperties::setTotalCrossSectionArea(double v) {
 std::string Ifc2x3::IfcReinforcementBarProperties::SteelGrade() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc2x3::IfcReinforcementBarProperties::setSteelGrade(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc2x3::IfcReinforcingBarSurfaceEnum::Value > Ifc2x3::IfcReinforcementBarProperties::BarSurface() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc2x3::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(2)); }
-void Ifc2x3::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc2x3::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc2x3::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc2x3::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcReinforcementBarProperties::EffectiveDepth() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcReinforcementBarProperties::NominalBarDiameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcReinforcementBarProperties::BarCount() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcReinforcementBarProperties::declaration() const { return *IFC2X3_IfcReinforcementBarProperties_type; }
@@ -14142,7 +14142,7 @@ Ifc2x3::IfcReinforcementBarProperties::IfcReinforcementBarProperties(double v1_T
 
 // Function implementations for IfcReinforcementDefinitionProperties
 boost::optional< std::string > Ifc2x3::IfcReinforcementDefinitionProperties::DefinitionType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc2x3::IfcSectionReinforcementProperties >::ptr Ifc2x3::IfcReinforcementDefinitionProperties::ReinforcementSectionDefinitions() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc2x3::IfcSectionReinforcementProperties >(); }
 void Ifc2x3::IfcReinforcementDefinitionProperties::setReinforcementSectionDefinitions(aggregate_of< ::Ifc2x3::IfcSectionReinforcementProperties >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -14158,11 +14158,11 @@ void Ifc2x3::IfcReinforcingBar::setNominalDiameter(double v) { {IfcWrite::IfcWri
 double Ifc2x3::IfcReinforcingBar::CrossSectionArea() const {  double v = *data_->getArgument(10); return v; }
 void Ifc2x3::IfcReinforcingBar::setCrossSectionArea(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcReinforcingBar::BarLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 ::Ifc2x3::IfcReinforcingBarRoleEnum::Value Ifc2x3::IfcReinforcingBar::BarRole() const {  return ::Ifc2x3::IfcReinforcingBarRoleEnum::FromString(*data_->getArgument(12)); }
 void Ifc2x3::IfcReinforcingBar::setBarRole(::Ifc2x3::IfcReinforcingBarRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcReinforcingBarRoleEnum::ToString(v)));data_->setArgument(12,attr);} }
 boost::optional< ::Ifc2x3::IfcReinforcingBarSurfaceEnum::Value > Ifc2x3::IfcReinforcingBar::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc2x3::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc2x3::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc2x3::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc2x3::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc2x3::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcReinforcingBar::declaration() const { return *IFC2X3_IfcReinforcingBar_type; }
@@ -14172,7 +14172,7 @@ Ifc2x3::IfcReinforcingBar::IfcReinforcingBar(std::string v1_GlobalId, ::Ifc2x3::
 
 // Function implementations for IfcReinforcingElement
 boost::optional< std::string > Ifc2x3::IfcReinforcingElement::SteelGrade() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcReinforcingElement::declaration() const { return *IFC2X3_IfcReinforcingElement_type; }
@@ -14182,9 +14182,9 @@ Ifc2x3::IfcReinforcingElement::IfcReinforcingElement(std::string v1_GlobalId, ::
 
 // Function implementations for IfcReinforcingMesh
 boost::optional< double > Ifc2x3::IfcReinforcingMesh::MeshLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcReinforcingMesh::MeshWidth() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 double Ifc2x3::IfcReinforcingMesh::LongitudinalBarNominalDiameter() const {  double v = *data_->getArgument(11); return v; }
 void Ifc2x3::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 double Ifc2x3::IfcReinforcingMesh::TransverseBarNominalDiameter() const {  double v = *data_->getArgument(12); return v; }
@@ -14216,7 +14216,7 @@ Ifc2x3::IfcRelAggregates::IfcRelAggregates(std::string v1_GlobalId, ::Ifc2x3::If
 aggregate_of< ::Ifc2x3::IfcObjectDefinition >::ptr Ifc2x3::IfcRelAssigns::RelatedObjects() const {  aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc2x3::IfcObjectDefinition >(); }
 void Ifc2x3::IfcRelAssigns::setRelatedObjects(aggregate_of< ::Ifc2x3::IfcObjectDefinition >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(4,attr);} }
 boost::optional< ::Ifc2x3::IfcObjectTypeEnum::Value > Ifc2x3::IfcRelAssigns::RelatedObjectsType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc2x3::IfcObjectTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc2x3::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc2x3::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcObjectTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc2x3::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc2x3::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcObjectTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcRelAssigns::declaration() const { return *IFC2X3_IfcRelAssigns_type; }
@@ -14500,7 +14500,7 @@ void Ifc2x3::IfcRelConnectsStructuralMember::setAppliedCondition(::Ifc2x3::IfcBo
 ::Ifc2x3::IfcStructuralConnectionCondition* Ifc2x3::IfcRelConnectsStructuralMember::AdditionalConditions() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc2x3::IfcStructuralConnectionCondition>(true); }
 void Ifc2x3::IfcRelConnectsStructuralMember::setAdditionalConditions(::Ifc2x3::IfcStructuralConnectionCondition* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcRelConnectsStructuralMember::SupportedLength() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc2x3::IfcAxis2Placement3D* Ifc2x3::IfcRelConnectsStructuralMember::ConditionCoordinateSystem() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc2x3::IfcAxis2Placement3D>(true); }
 void Ifc2x3::IfcRelConnectsStructuralMember::setConditionCoordinateSystem(::Ifc2x3::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -14524,7 +14524,7 @@ Ifc2x3::IfcRelConnectsWithEccentricity::IfcRelConnectsWithEccentricity(std::stri
 aggregate_of< ::Ifc2x3::IfcElement >::ptr Ifc2x3::IfcRelConnectsWithRealizingElements::RealizingElements() const {  aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc2x3::IfcElement >(); }
 void Ifc2x3::IfcRelConnectsWithRealizingElements::setRealizingElements(aggregate_of< ::Ifc2x3::IfcElement >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc2x3::IfcRelConnectsWithRealizingElements::ConnectionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcRelConnectsWithRealizingElements::declaration() const { return *IFC2X3_IfcRelConnectsWithRealizingElements_type; }
@@ -14636,9 +14636,9 @@ Ifc2x3::IfcRelFlowControlElements::IfcRelFlowControlElements(std::string v1_Glob
 
 // Function implementations for IfcRelInteractionRequirements
 boost::optional< double > Ifc2x3::IfcRelInteractionRequirements::DailyInteraction() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcRelInteractionRequirements::setDailyInteraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcRelInteractionRequirements::setDailyInteraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcRelInteractionRequirements::ImportanceRating() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcRelInteractionRequirements::setImportanceRating(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcRelInteractionRequirements::setImportanceRating(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc2x3::IfcSpatialStructureElement* Ifc2x3::IfcRelInteractionRequirements::LocationOfInteraction() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc2x3::IfcSpatialStructureElement>(true); }
 void Ifc2x3::IfcRelInteractionRequirements::setLocationOfInteraction(::Ifc2x3::IfcSpatialStructureElement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 ::Ifc2x3::IfcSpaceProgram* Ifc2x3::IfcRelInteractionRequirements::RelatedSpaceProgram() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc2x3::IfcSpaceProgram>(true); }
@@ -14792,9 +14792,9 @@ Ifc2x3::IfcRelaxation::IfcRelaxation(double v1_RelaxationValue, double v2_Initia
 ::Ifc2x3::IfcRepresentationContext* Ifc2x3::IfcRepresentation::ContextOfItems() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc2x3::IfcRepresentationContext>(true); }
 void Ifc2x3::IfcRepresentation::setContextOfItems(::Ifc2x3::IfcRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcRepresentation::RepresentationIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcRepresentation::RepresentationType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc2x3::IfcRepresentationItem >::ptr Ifc2x3::IfcRepresentation::Items() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc2x3::IfcRepresentationItem >(); }
 void Ifc2x3::IfcRepresentation::setItems(aggregate_of< ::Ifc2x3::IfcRepresentationItem >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 
@@ -14809,9 +14809,9 @@ Ifc2x3::IfcRepresentation::IfcRepresentation(::Ifc2x3::IfcRepresentationContext*
 
 // Function implementations for IfcRepresentationContext
 boost::optional< std::string > Ifc2x3::IfcRepresentationContext::ContextIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcRepresentationContext::ContextType() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc2x3::IfcRepresentation::list::ptr Ifc2x3::IfcRepresentationContext::RepresentationsInContext() const { return data_->getInverse(IFC2X3_IfcRepresentation_type, 0)->as<IfcRepresentation>(); }
 
@@ -14866,13 +14866,13 @@ Ifc2x3::IfcRevolvedAreaSolid::IfcRevolvedAreaSolid(::Ifc2x3::IfcProfileDef* v1_S
 
 // Function implementations for IfcRibPlateProfileProperties
 boost::optional< double > Ifc2x3::IfcRibPlateProfileProperties::Thickness() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcRibPlateProfileProperties::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcRibPlateProfileProperties::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcRibPlateProfileProperties::RibHeight() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcRibPlateProfileProperties::setRibHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcRibPlateProfileProperties::setRibHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcRibPlateProfileProperties::RibWidth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcRibPlateProfileProperties::setRibWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcRibPlateProfileProperties::setRibWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcRibPlateProfileProperties::RibSpacing() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcRibPlateProfileProperties::setRibSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcRibPlateProfileProperties::setRibSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc2x3::IfcRibPlateDirectionEnum::Value Ifc2x3::IfcRibPlateProfileProperties::Direction() const {  return ::Ifc2x3::IfcRibPlateDirectionEnum::FromString(*data_->getArgument(6)); }
 void Ifc2x3::IfcRibPlateProfileProperties::setDirection(::Ifc2x3::IfcRibPlateDirectionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcRibPlateDirectionEnum::ToString(v)));data_->setArgument(6,attr);} }
 
@@ -14922,9 +14922,9 @@ void Ifc2x3::IfcRoot::setGlobalId(std::string v) { {IfcWrite::IfcWriteArgument*
 ::Ifc2x3::IfcOwnerHistory* Ifc2x3::IfcRoot::OwnerHistory() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc2x3::IfcOwnerHistory>(true); }
 void Ifc2x3::IfcRoot::setOwnerHistory(::Ifc2x3::IfcOwnerHistory* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcRoot::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc2x3::IfcRoot::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcRoot::declaration() const { return *IFC2X3_IfcRoot_type; }
@@ -14934,7 +14934,7 @@ Ifc2x3::IfcRoot::IfcRoot(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory* v2_
 
 // Function implementations for IfcRoundedEdgeFeature
 boost::optional< double > Ifc2x3::IfcRoundedEdgeFeature::Radius() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcRoundedEdgeFeature::setRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcRoundedEdgeFeature::setRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcRoundedEdgeFeature::declaration() const { return *IFC2X3_IfcRoundedEdgeFeature_type; }
@@ -14954,7 +14954,7 @@ Ifc2x3::IfcRoundedRectangleProfileDef::IfcRoundedRectangleProfileDef(::Ifc2x3::I
 
 // Function implementations for IfcSIUnit
 boost::optional< ::Ifc2x3::IfcSIPrefix::Value > Ifc2x3::IfcSIUnit::Prefix() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc2x3::IfcSIPrefix::FromString(*data_->getArgument(2)); }
-void Ifc2x3::IfcSIUnit::setPrefix(boost::optional< ::Ifc2x3::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcSIPrefix::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc2x3::IfcSIUnit::setPrefix(boost::optional< ::Ifc2x3::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcSIPrefix::ToString(*v)));}data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcSIUnitName::Value Ifc2x3::IfcSIUnit::Name() const {  return ::Ifc2x3::IfcSIUnitName::FromString(*data_->getArgument(3)); }
 void Ifc2x3::IfcSIUnit::setName(::Ifc2x3::IfcSIUnitName::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcSIUnitName::ToString(v)));data_->setArgument(3,attr);} }
 
@@ -14992,25 +14992,25 @@ void Ifc2x3::IfcScheduleTimeControl::setLateFinish(::Ifc2x3::IfcDateTimeSelect*
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcScheduleTimeControl::ScheduleFinish() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(12)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
 void Ifc2x3::IfcScheduleTimeControl::setScheduleFinish(::Ifc2x3::IfcDateTimeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(12,attr);} }
 boost::optional< double > Ifc2x3::IfcScheduleTimeControl::ScheduleDuration() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc2x3::IfcScheduleTimeControl::setScheduleDuration(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc2x3::IfcScheduleTimeControl::setScheduleDuration(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc2x3::IfcScheduleTimeControl::ActualDuration() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc2x3::IfcScheduleTimeControl::setActualDuration(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc2x3::IfcScheduleTimeControl::setActualDuration(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc2x3::IfcScheduleTimeControl::RemainingTime() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc2x3::IfcScheduleTimeControl::setRemainingTime(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc2x3::IfcScheduleTimeControl::setRemainingTime(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc2x3::IfcScheduleTimeControl::FreeFloat() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc2x3::IfcScheduleTimeControl::setFreeFloat(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc2x3::IfcScheduleTimeControl::setFreeFloat(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc2x3::IfcScheduleTimeControl::TotalFloat() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc2x3::IfcScheduleTimeControl::setTotalFloat(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc2x3::IfcScheduleTimeControl::setTotalFloat(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< bool > Ifc2x3::IfcScheduleTimeControl::IsCritical() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } bool v = *data_->getArgument(18); return v; }
-void Ifc2x3::IfcScheduleTimeControl::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc2x3::IfcScheduleTimeControl::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcScheduleTimeControl::StatusTime() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(19)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
 void Ifc2x3::IfcScheduleTimeControl::setStatusTime(::Ifc2x3::IfcDateTimeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(19,attr);} }
 boost::optional< double > Ifc2x3::IfcScheduleTimeControl::StartFloat() const { if(!data_->getArgument(20) || data_->getArgument(20)->isNull()) { return boost::none; } double v = *data_->getArgument(20); return v; }
-void Ifc2x3::IfcScheduleTimeControl::setStartFloat(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(20,attr);} }
+void Ifc2x3::IfcScheduleTimeControl::setStartFloat(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(20,attr);} }
 boost::optional< double > Ifc2x3::IfcScheduleTimeControl::FinishFloat() const { if(!data_->getArgument(21) || data_->getArgument(21)->isNull()) { return boost::none; } double v = *data_->getArgument(21); return v; }
-void Ifc2x3::IfcScheduleTimeControl::setFinishFloat(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(21,attr);} }
+void Ifc2x3::IfcScheduleTimeControl::setFinishFloat(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(21,attr);} }
 boost::optional< double > Ifc2x3::IfcScheduleTimeControl::Completion() const { if(!data_->getArgument(22) || data_->getArgument(22)->isNull()) { return boost::none; } double v = *data_->getArgument(22); return v; }
-void Ifc2x3::IfcScheduleTimeControl::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(22,attr);} }
+void Ifc2x3::IfcScheduleTimeControl::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(22,attr);} }
 
 ::Ifc2x3::IfcRelAssignsTasks::list::ptr Ifc2x3::IfcScheduleTimeControl::ScheduleTimeControlAssigned() const { return data_->getInverse(IFC2X3_IfcRelAssignsTasks_type, 7)->as<IfcRelAssignsTasks>(); }
 
@@ -15039,7 +15039,7 @@ void Ifc2x3::IfcSectionReinforcementProperties::setLongitudinalStartPosition(dou
 double Ifc2x3::IfcSectionReinforcementProperties::LongitudinalEndPosition() const {  double v = *data_->getArgument(1); return v; }
 void Ifc2x3::IfcSectionReinforcementProperties::setLongitudinalEndPosition(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcSectionReinforcementProperties::TransversePosition() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcReinforcingBarRoleEnum::Value Ifc2x3::IfcSectionReinforcementProperties::ReinforcementRole() const {  return ::Ifc2x3::IfcReinforcingBarRoleEnum::FromString(*data_->getArgument(3)); }
 void Ifc2x3::IfcSectionReinforcementProperties::setReinforcementRole(::Ifc2x3::IfcReinforcingBarRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcReinforcingBarRoleEnum::ToString(v)));data_->setArgument(3,attr);} }
 ::Ifc2x3::IfcSectionProperties* Ifc2x3::IfcSectionReinforcementProperties::SectionDefinition() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc2x3::IfcSectionProperties>(true); }
@@ -15109,9 +15109,9 @@ Ifc2x3::IfcServiceLifeFactor::IfcServiceLifeFactor(std::string v1_GlobalId, ::If
 aggregate_of< ::Ifc2x3::IfcShapeModel >::ptr Ifc2x3::IfcShapeAspect::ShapeRepresentations() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc2x3::IfcShapeModel >(); }
 void Ifc2x3::IfcShapeAspect::setShapeRepresentations(aggregate_of< ::Ifc2x3::IfcShapeModel >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcShapeAspect::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcShapeAspect::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::logic::tribool Ifc2x3::IfcShapeAspect::ProductDefinitional() const {  boost::logic::tribool v = *data_->getArgument(3); return v; }
 void Ifc2x3::IfcShapeAspect::setProductDefinitional(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc2x3::IfcProductDefinitionShape* Ifc2x3::IfcShapeAspect::PartOfProductDefinitionShape() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc2x3::IfcProductDefinitionShape>(true); }
@@ -15160,13 +15160,13 @@ Ifc2x3::IfcSimpleProperty::IfcSimpleProperty(std::string v1_Name, boost::optiona
 
 // Function implementations for IfcSite
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc2x3::IfcSite::RefLatitude() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc2x3::IfcSite::RefLongitude() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcSite::RefElevation() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc2x3::IfcSite::LandTitleNumber() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc2x3::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc2x3::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc2x3::IfcPostalAddress* Ifc2x3::IfcSite::SiteAddress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc2x3::IfcPostalAddress>(true); }
 void Ifc2x3::IfcSite::setSiteAddress(::Ifc2x3::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -15178,7 +15178,7 @@ Ifc2x3::IfcSite::IfcSite(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory* v2_
 
 // Function implementations for IfcSlab
 boost::optional< ::Ifc2x3::IfcSlabTypeEnum::Value > Ifc2x3::IfcSlab::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc2x3::IfcSlabTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc2x3::IfcSlab::setPredefinedType(boost::optional< ::Ifc2x3::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcSlabTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc2x3::IfcSlab::setPredefinedType(boost::optional< ::Ifc2x3::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcSlabTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcSlab::declaration() const { return *IFC2X3_IfcSlab_type; }
@@ -15198,11 +15198,11 @@ Ifc2x3::IfcSlabType::IfcSlabType(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHist
 
 // Function implementations for IfcSlippageConnectionCondition
 boost::optional< double > Ifc2x3::IfcSlippageConnectionCondition::SlippageX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcSlippageConnectionCondition::SlippageY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcSlippageConnectionCondition::SlippageZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcSlippageConnectionCondition::declaration() const { return *IFC2X3_IfcSlippageConnectionCondition_type; }
@@ -15222,7 +15222,7 @@ Ifc2x3::IfcSolidModel::IfcSolidModel() : IfcGeometricRepresentationItem((IfcEnti
 bool Ifc2x3::IfcSoundProperties::IsAttenuating() const {  bool v = *data_->getArgument(4); return v; }
 void Ifc2x3::IfcSoundProperties::setIsAttenuating(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< ::Ifc2x3::IfcSoundScaleEnum::Value > Ifc2x3::IfcSoundProperties::SoundScale() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc2x3::IfcSoundScaleEnum::FromString(*data_->getArgument(5)); }
-void Ifc2x3::IfcSoundProperties::setSoundScale(boost::optional< ::Ifc2x3::IfcSoundScaleEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcSoundScaleEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc2x3::IfcSoundProperties::setSoundScale(boost::optional< ::Ifc2x3::IfcSoundScaleEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcSoundScaleEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 aggregate_of< ::Ifc2x3::IfcSoundValue >::ptr Ifc2x3::IfcSoundProperties::SoundValues() const {  aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc2x3::IfcSoundValue >(); }
 void Ifc2x3::IfcSoundProperties::setSoundValues(aggregate_of< ::Ifc2x3::IfcSoundValue >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(6,attr);} }
 
@@ -15250,7 +15250,7 @@ Ifc2x3::IfcSoundValue::IfcSoundValue(std::string v1_GlobalId, ::Ifc2x3::IfcOwner
 ::Ifc2x3::IfcInternalOrExternalEnum::Value Ifc2x3::IfcSpace::InteriorOrExteriorSpace() const {  return ::Ifc2x3::IfcInternalOrExternalEnum::FromString(*data_->getArgument(9)); }
 void Ifc2x3::IfcSpace::setInteriorOrExteriorSpace(::Ifc2x3::IfcInternalOrExternalEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcInternalOrExternalEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcSpace::ElevationWithFlooring() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 ::Ifc2x3::IfcRelCoversSpaces::list::ptr Ifc2x3::IfcSpace::HasCoverings() const { return data_->getInverse(IFC2X3_IfcRelCoversSpaces_type, 4)->as<IfcRelCoversSpaces>(); }
 ::Ifc2x3::IfcRelSpaceBoundary::list::ptr Ifc2x3::IfcSpace::BoundedBy() const { return data_->getInverse(IFC2X3_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
@@ -15274,9 +15274,9 @@ Ifc2x3::IfcSpaceHeaterType::IfcSpaceHeaterType(std::string v1_GlobalId, ::Ifc2x3
 std::string Ifc2x3::IfcSpaceProgram::SpaceProgramIdentifier() const {  std::string v = *data_->getArgument(5); return v; }
 void Ifc2x3::IfcSpaceProgram::setSpaceProgramIdentifier(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcSpaceProgram::MaxRequiredArea() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcSpaceProgram::setMaxRequiredArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcSpaceProgram::setMaxRequiredArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcSpaceProgram::MinRequiredArea() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcSpaceProgram::setMinRequiredArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcSpaceProgram::setMinRequiredArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc2x3::IfcSpatialStructureElement* Ifc2x3::IfcSpaceProgram::RequestedLocation() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc2x3::IfcSpatialStructureElement>(true); }
 void Ifc2x3::IfcSpaceProgram::setRequestedLocation(::Ifc2x3::IfcSpatialStructureElement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 double Ifc2x3::IfcSpaceProgram::StandardRequiredArea() const {  double v = *data_->getArgument(9); return v; }
@@ -15292,23 +15292,23 @@ Ifc2x3::IfcSpaceProgram::IfcSpaceProgram(std::string v1_GlobalId, ::Ifc2x3::IfcO
 
 // Function implementations for IfcSpaceThermalLoadProperties
 boost::optional< double > Ifc2x3::IfcSpaceThermalLoadProperties::ApplicableValueRatio() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcSpaceThermalLoadProperties::setApplicableValueRatio(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcSpaceThermalLoadProperties::setApplicableValueRatio(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc2x3::IfcThermalLoadSourceEnum::Value Ifc2x3::IfcSpaceThermalLoadProperties::ThermalLoadSource() const {  return ::Ifc2x3::IfcThermalLoadSourceEnum::FromString(*data_->getArgument(5)); }
 void Ifc2x3::IfcSpaceThermalLoadProperties::setThermalLoadSource(::Ifc2x3::IfcThermalLoadSourceEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcThermalLoadSourceEnum::ToString(v)));data_->setArgument(5,attr);} }
 ::Ifc2x3::IfcPropertySourceEnum::Value Ifc2x3::IfcSpaceThermalLoadProperties::PropertySource() const {  return ::Ifc2x3::IfcPropertySourceEnum::FromString(*data_->getArgument(6)); }
 void Ifc2x3::IfcSpaceThermalLoadProperties::setPropertySource(::Ifc2x3::IfcPropertySourceEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcPropertySourceEnum::ToString(v)));data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc2x3::IfcSpaceThermalLoadProperties::SourceDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcSpaceThermalLoadProperties::setSourceDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcSpaceThermalLoadProperties::setSourceDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 double Ifc2x3::IfcSpaceThermalLoadProperties::MaximumValue() const {  double v = *data_->getArgument(8); return v; }
 void Ifc2x3::IfcSpaceThermalLoadProperties::setMaximumValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcSpaceThermalLoadProperties::MinimumValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcSpaceThermalLoadProperties::setMinimumValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcSpaceThermalLoadProperties::setMinimumValue(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 ::Ifc2x3::IfcTimeSeries* Ifc2x3::IfcSpaceThermalLoadProperties::ThermalLoadTimeSeriesValues() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc2x3::IfcTimeSeries>(true); }
 void Ifc2x3::IfcSpaceThermalLoadProperties::setThermalLoadTimeSeriesValues(::Ifc2x3::IfcTimeSeries* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc2x3::IfcSpaceThermalLoadProperties::UserDefinedThermalLoadSource() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcSpaceThermalLoadProperties::setUserDefinedThermalLoadSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcSpaceThermalLoadProperties::setUserDefinedThermalLoadSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc2x3::IfcSpaceThermalLoadProperties::UserDefinedPropertySource() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc2x3::IfcSpaceThermalLoadProperties::setUserDefinedPropertySource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc2x3::IfcSpaceThermalLoadProperties::setUserDefinedPropertySource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc2x3::IfcThermalLoadTypeEnum::Value Ifc2x3::IfcSpaceThermalLoadProperties::ThermalLoadType() const {  return ::Ifc2x3::IfcThermalLoadTypeEnum::FromString(*data_->getArgument(13)); }
 void Ifc2x3::IfcSpaceThermalLoadProperties::setThermalLoadType(::Ifc2x3::IfcThermalLoadTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcThermalLoadTypeEnum::ToString(v)));data_->setArgument(13,attr);} }
 
@@ -15330,7 +15330,7 @@ Ifc2x3::IfcSpaceType::IfcSpaceType(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHi
 
 // Function implementations for IfcSpatialStructureElement
 boost::optional< std::string > Ifc2x3::IfcSpatialStructureElement::LongName() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcSpatialStructureElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcSpatialStructureElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc2x3::IfcElementCompositionEnum::Value Ifc2x3::IfcSpatialStructureElement::CompositionType() const {  return ::Ifc2x3::IfcElementCompositionEnum::FromString(*data_->getArgument(8)); }
 void Ifc2x3::IfcSpatialStructureElement::setCompositionType(::Ifc2x3::IfcElementCompositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcElementCompositionEnum::ToString(v)));data_->setArgument(8,attr);} }
 
@@ -15383,13 +15383,13 @@ Ifc2x3::IfcStair::IfcStair(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory* v
 
 // Function implementations for IfcStairFlight
 boost::optional< int > Ifc2x3::IfcStairFlight::NumberOfRiser() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } int v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcStairFlight::setNumberOfRiser(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcStairFlight::setNumberOfRiser(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< int > Ifc2x3::IfcStairFlight::NumberOfTreads() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } int v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcStairFlight::RiserHeight() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcStairFlight::TreadLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStairFlight::declaration() const { return *IFC2X3_IfcStairFlight_type; }
@@ -15438,9 +15438,9 @@ void Ifc2x3::IfcStructuralAnalysisModel::setPredefinedType(::Ifc2x3::IfcAnalysis
 ::Ifc2x3::IfcAxis2Placement3D* Ifc2x3::IfcStructuralAnalysisModel::OrientationOf2DPlane() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc2x3::IfcAxis2Placement3D>(true); }
 void Ifc2x3::IfcStructuralAnalysisModel::setOrientationOf2DPlane(::Ifc2x3::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcStructuralLoadGroup >::ptr > Ifc2x3::IfcStructuralAnalysisModel::LoadedBy() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc2x3::IfcStructuralLoadGroup >(); }
-void Ifc2x3::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc2x3::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc2x3::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc2x3::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcStructuralResultGroup >::ptr > Ifc2x3::IfcStructuralAnalysisModel::HasResults() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc2x3::IfcStructuralResultGroup >(); }
-void Ifc2x3::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc2x3::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc2x3::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc2x3::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralAnalysisModel::declaration() const { return *IFC2X3_IfcStructuralAnalysisModel_type; }
@@ -15461,7 +15461,7 @@ Ifc2x3::IfcStructuralConnection::IfcStructuralConnection(std::string v1_GlobalId
 
 // Function implementations for IfcStructuralConnectionCondition
 boost::optional< std::string > Ifc2x3::IfcStructuralConnectionCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralConnectionCondition::declaration() const { return *IFC2X3_IfcStructuralConnectionCondition_type; }
@@ -15528,7 +15528,7 @@ Ifc2x3::IfcStructuralLinearActionVarying::IfcStructuralLinearActionVarying(std::
 
 // Function implementations for IfcStructuralLoad
 boost::optional< std::string > Ifc2x3::IfcStructuralLoad::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralLoad::declaration() const { return *IFC2X3_IfcStructuralLoad_type; }
@@ -15544,9 +15544,9 @@ void Ifc2x3::IfcStructuralLoadGroup::setActionType(::Ifc2x3::IfcActionTypeEnum::
 ::Ifc2x3::IfcActionSourceTypeEnum::Value Ifc2x3::IfcStructuralLoadGroup::ActionSource() const {  return ::Ifc2x3::IfcActionSourceTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc2x3::IfcStructuralLoadGroup::setActionSource(::Ifc2x3::IfcActionSourceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcActionSourceTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadGroup::Coefficient() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc2x3::IfcStructuralLoadGroup::Purpose() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 ::Ifc2x3::IfcStructuralResultGroup::list::ptr Ifc2x3::IfcStructuralLoadGroup::SourceOfResultGroup() const { return data_->getInverse(IFC2X3_IfcStructuralResultGroup_type, 6)->as<IfcStructuralResultGroup>(); }
 ::Ifc2x3::IfcStructuralAnalysisModel::list::ptr Ifc2x3::IfcStructuralLoadGroup::LoadGroupFor() const { return data_->getInverse(IFC2X3_IfcStructuralAnalysisModel_type, 7)->as<IfcStructuralAnalysisModel>(); }
@@ -15558,17 +15558,17 @@ Ifc2x3::IfcStructuralLoadGroup::IfcStructuralLoadGroup(std::string v1_GlobalId,
 
 // Function implementations for IfcStructuralLoadLinearForce
 boost::optional< double > Ifc2x3::IfcStructuralLoadLinearForce::LinearForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadLinearForce::LinearForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadLinearForce::LinearForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadLinearForce::LinearMomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadLinearForce::LinearMomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadLinearForce::LinearMomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralLoadLinearForce::declaration() const { return *IFC2X3_IfcStructuralLoadLinearForce_type; }
@@ -15578,11 +15578,11 @@ Ifc2x3::IfcStructuralLoadLinearForce::IfcStructuralLoadLinearForce(boost::option
 
 // Function implementations for IfcStructuralLoadPlanarForce
 boost::optional< double > Ifc2x3::IfcStructuralLoadPlanarForce::PlanarForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadPlanarForce::PlanarForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadPlanarForce::PlanarForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralLoadPlanarForce::declaration() const { return *IFC2X3_IfcStructuralLoadPlanarForce_type; }
@@ -15592,17 +15592,17 @@ Ifc2x3::IfcStructuralLoadPlanarForce::IfcStructuralLoadPlanarForce(boost::option
 
 // Function implementations for IfcStructuralLoadSingleDisplacement
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleDisplacement::DisplacementX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleDisplacement::DisplacementY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleDisplacement::DisplacementZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralLoadSingleDisplacement::declaration() const { return *IFC2X3_IfcStructuralLoadSingleDisplacement_type; }
@@ -15612,7 +15612,7 @@ Ifc2x3::IfcStructuralLoadSingleDisplacement::IfcStructuralLoadSingleDisplacement
 
 // Function implementations for IfcStructuralLoadSingleDisplacementDistortion
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleDisplacementDistortion::Distortion() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralLoadSingleDisplacementDistortion::declaration() const { return *IFC2X3_IfcStructuralLoadSingleDisplacementDistortion_type; }
@@ -15622,17 +15622,17 @@ Ifc2x3::IfcStructuralLoadSingleDisplacementDistortion::IfcStructuralLoadSingleDi
 
 // Function implementations for IfcStructuralLoadSingleForce
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleForce::ForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleForce::ForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleForce::ForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleForce::MomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleForce::MomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleForce::MomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralLoadSingleForce::declaration() const { return *IFC2X3_IfcStructuralLoadSingleForce_type; }
@@ -15642,7 +15642,7 @@ Ifc2x3::IfcStructuralLoadSingleForce::IfcStructuralLoadSingleForce(boost::option
 
 // Function implementations for IfcStructuralLoadSingleForceWarping
 boost::optional< double > Ifc2x3::IfcStructuralLoadSingleForceWarping::WarpingMoment() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralLoadSingleForceWarping::declaration() const { return *IFC2X3_IfcStructuralLoadSingleForceWarping_type; }
@@ -15660,11 +15660,11 @@ Ifc2x3::IfcStructuralLoadStatic::IfcStructuralLoadStatic(boost::optional< std::s
 
 // Function implementations for IfcStructuralLoadTemperature
 boost::optional< double > Ifc2x3::IfcStructuralLoadTemperature::DeltaT_Constant() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcStructuralLoadTemperature::setDeltaT_Constant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcStructuralLoadTemperature::setDeltaT_Constant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadTemperature::DeltaT_Y() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcStructuralLoadTemperature::setDeltaT_Y(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcStructuralLoadTemperature::setDeltaT_Y(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralLoadTemperature::DeltaT_Z() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcStructuralLoadTemperature::setDeltaT_Z(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcStructuralLoadTemperature::setDeltaT_Z(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralLoadTemperature::declaration() const { return *IFC2X3_IfcStructuralLoadTemperature_type; }
@@ -15730,37 +15730,37 @@ Ifc2x3::IfcStructuralPointReaction::IfcStructuralPointReaction(std::string v1_Gl
 
 // Function implementations for IfcStructuralProfileProperties
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::TorsionalConstantX() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setTorsionalConstantX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setTorsionalConstantX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::MomentOfInertiaYZ() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setMomentOfInertiaYZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setMomentOfInertiaYZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::MomentOfInertiaY() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setMomentOfInertiaY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setMomentOfInertiaY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::MomentOfInertiaZ() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setMomentOfInertiaZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setMomentOfInertiaZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::WarpingConstant() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setWarpingConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setWarpingConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::ShearCentreZ() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setShearCentreZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setShearCentreZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::ShearCentreY() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setShearCentreY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setShearCentreY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::ShearDeformationAreaZ() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setShearDeformationAreaZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setShearDeformationAreaZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::ShearDeformationAreaY() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setShearDeformationAreaY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setShearDeformationAreaY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::MaximumSectionModulusY() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setMaximumSectionModulusY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setMaximumSectionModulusY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::MinimumSectionModulusY() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setMinimumSectionModulusY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setMinimumSectionModulusY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::MaximumSectionModulusZ() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } double v = *data_->getArgument(18); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setMaximumSectionModulusZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setMaximumSectionModulusZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::MinimumSectionModulusZ() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } double v = *data_->getArgument(19); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setMinimumSectionModulusZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setMinimumSectionModulusZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::TorsionalSectionModulus() const { if(!data_->getArgument(20) || data_->getArgument(20)->isNull()) { return boost::none; } double v = *data_->getArgument(20); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setTorsionalSectionModulus(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(20,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setTorsionalSectionModulus(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(20,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::CentreOfGravityInX() const { if(!data_->getArgument(21) || data_->getArgument(21)->isNull()) { return boost::none; } double v = *data_->getArgument(21); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setCentreOfGravityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(21,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setCentreOfGravityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(21,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralProfileProperties::CentreOfGravityInY() const { if(!data_->getArgument(22) || data_->getArgument(22)->isNull()) { return boost::none; } double v = *data_->getArgument(22); return v; }
-void Ifc2x3::IfcStructuralProfileProperties::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(22,attr);} }
+void Ifc2x3::IfcStructuralProfileProperties::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(22,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralProfileProperties::declaration() const { return *IFC2X3_IfcStructuralProfileProperties_type; }
@@ -15794,13 +15794,13 @@ Ifc2x3::IfcStructuralResultGroup::IfcStructuralResultGroup(std::string v1_Global
 
 // Function implementations for IfcStructuralSteelProfileProperties
 boost::optional< double > Ifc2x3::IfcStructuralSteelProfileProperties::ShearAreaZ() const { if(!data_->getArgument(23) || data_->getArgument(23)->isNull()) { return boost::none; } double v = *data_->getArgument(23); return v; }
-void Ifc2x3::IfcStructuralSteelProfileProperties::setShearAreaZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(23,attr);} }
+void Ifc2x3::IfcStructuralSteelProfileProperties::setShearAreaZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(23,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralSteelProfileProperties::ShearAreaY() const { if(!data_->getArgument(24) || data_->getArgument(24)->isNull()) { return boost::none; } double v = *data_->getArgument(24); return v; }
-void Ifc2x3::IfcStructuralSteelProfileProperties::setShearAreaY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(24,attr);} }
+void Ifc2x3::IfcStructuralSteelProfileProperties::setShearAreaY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(24,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralSteelProfileProperties::PlasticShapeFactorY() const { if(!data_->getArgument(25) || data_->getArgument(25)->isNull()) { return boost::none; } double v = *data_->getArgument(25); return v; }
-void Ifc2x3::IfcStructuralSteelProfileProperties::setPlasticShapeFactorY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(25,attr);} }
+void Ifc2x3::IfcStructuralSteelProfileProperties::setPlasticShapeFactorY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(25,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralSteelProfileProperties::PlasticShapeFactorZ() const { if(!data_->getArgument(26) || data_->getArgument(26)->isNull()) { return boost::none; } double v = *data_->getArgument(26); return v; }
-void Ifc2x3::IfcStructuralSteelProfileProperties::setPlasticShapeFactorZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(26,attr);} }
+void Ifc2x3::IfcStructuralSteelProfileProperties::setPlasticShapeFactorZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(26,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralSteelProfileProperties::declaration() const { return *IFC2X3_IfcStructuralSteelProfileProperties_type; }
@@ -15820,7 +15820,7 @@ Ifc2x3::IfcStructuralSurfaceConnection::IfcStructuralSurfaceConnection(std::stri
 ::Ifc2x3::IfcStructuralSurfaceTypeEnum::Value Ifc2x3::IfcStructuralSurfaceMember::PredefinedType() const {  return ::Ifc2x3::IfcStructuralSurfaceTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc2x3::IfcStructuralSurfaceMember::setPredefinedType(::Ifc2x3::IfcStructuralSurfaceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcStructuralSurfaceTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcStructuralSurfaceMember::Thickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStructuralSurfaceMember::declaration() const { return *IFC2X3_IfcStructuralSurfaceMember_type; }
@@ -15862,7 +15862,7 @@ void Ifc2x3::IfcStyledItem::setItem(::Ifc2x3::IfcRepresentationItem* v) { {IfcWr
 aggregate_of< ::Ifc2x3::IfcPresentationStyleAssignment >::ptr Ifc2x3::IfcStyledItem::Styles() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc2x3::IfcPresentationStyleAssignment >(); }
 void Ifc2x3::IfcStyledItem::setStyles(aggregate_of< ::Ifc2x3::IfcPresentationStyleAssignment >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcStyledItem::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcStyledItem::declaration() const { return *IFC2X3_IfcStyledItem_type; }
@@ -15882,7 +15882,7 @@ Ifc2x3::IfcStyledRepresentation::IfcStyledRepresentation(::Ifc2x3::IfcRepresenta
 ::Ifc2x3::IfcActorSelect* Ifc2x3::IfcSubContractResource::SubContractor() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc2x3::IfcActorSelect>(true); }
 void Ifc2x3::IfcSubContractResource::setSubContractor(::Ifc2x3::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc2x3::IfcSubContractResource::JobDescription() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcSubContractResource::setJobDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcSubContractResource::setJobDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcSubContractResource::declaration() const { return *IFC2X3_IfcSubContractResource_type; }
@@ -15976,9 +15976,9 @@ Ifc2x3::IfcSurfaceStyleLighting::IfcSurfaceStyleLighting(::Ifc2x3::IfcColourRgb*
 
 // Function implementations for IfcSurfaceStyleRefraction
 boost::optional< double > Ifc2x3::IfcSurfaceStyleRefraction::RefractionIndex() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< double > Ifc2x3::IfcSurfaceStyleRefraction::DispersionFactor() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcSurfaceStyleRefraction::declaration() const { return *IFC2X3_IfcSurfaceStyleRefraction_type; }
@@ -15988,7 +15988,7 @@ Ifc2x3::IfcSurfaceStyleRefraction::IfcSurfaceStyleRefraction(boost::optional< do
 
 // Function implementations for IfcSurfaceStyleRendering
 boost::optional< double > Ifc2x3::IfcSurfaceStyleRendering::Transparency() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcSurfaceStyleRendering::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcSurfaceStyleRendering::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc2x3::IfcColourOrFactor* Ifc2x3::IfcSurfaceStyleRendering::DiffuseColour() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc2x3::IfcColourOrFactor>(true); }
 void Ifc2x3::IfcSurfaceStyleRendering::setDiffuseColour(::Ifc2x3::IfcColourOrFactor* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcColourOrFactor* Ifc2x3::IfcSurfaceStyleRendering::TransmissionColour() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc2x3::IfcColourOrFactor>(true); }
@@ -16064,7 +16064,7 @@ void Ifc2x3::IfcSweptDiskSolid::setDirectrix(::Ifc2x3::IfcCurve* v) { {IfcWrite:
 double Ifc2x3::IfcSweptDiskSolid::Radius() const {  double v = *data_->getArgument(1); return v; }
 void Ifc2x3::IfcSweptDiskSolid::setRadius(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcSweptDiskSolid::InnerRadius() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 double Ifc2x3::IfcSweptDiskSolid::StartParam() const {  double v = *data_->getArgument(3); return v; }
 void Ifc2x3::IfcSweptDiskSolid::setStartParam(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 double Ifc2x3::IfcSweptDiskSolid::EndParam() const {  double v = *data_->getArgument(4); return v; }
@@ -16135,17 +16135,17 @@ void Ifc2x3::IfcTShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc2x3::IfcTShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc2x3::IfcTShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcTShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcTShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcTShapeProfileDef::WebEdgeRadius() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcTShapeProfileDef::WebSlope() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcTShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc2x3::IfcTShapeProfileDef::CentreOfGravityInY() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc2x3::IfcTShapeProfileDef::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc2x3::IfcTShapeProfileDef::setCentreOfGravityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcTShapeProfileDef::declaration() const { return *IFC2X3_IfcTShapeProfileDef_type; }
@@ -16192,13 +16192,13 @@ Ifc2x3::IfcTankType::IfcTankType(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHist
 std::string Ifc2x3::IfcTask::TaskId() const {  std::string v = *data_->getArgument(5); return v; }
 void Ifc2x3::IfcTask::setTaskId(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTask::Status() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTask::WorkMethod() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 bool Ifc2x3::IfcTask::IsMilestone() const {  bool v = *data_->getArgument(8); return v; }
 void Ifc2x3::IfcTask::setIsMilestone(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< int > Ifc2x3::IfcTask::Priority() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } int v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcTask::declaration() const { return *IFC2X3_IfcTask_type; }
@@ -16208,15 +16208,15 @@ Ifc2x3::IfcTask::IfcTask(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory* v2_
 
 // Function implementations for IfcTelecomAddress
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc2x3::IfcTelecomAddress::TelephoneNumbers() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc2x3::IfcTelecomAddress::FacsimileNumbers() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTelecomAddress::PagerNumber() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc2x3::IfcTelecomAddress::ElectronicMailAddresses() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTelecomAddress::WWWHomePageURL() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcTelecomAddress::declaration() const { return *IFC2X3_IfcTelecomAddress_type; }
@@ -16232,15 +16232,15 @@ void Ifc2x3::IfcTendon::setNominalDiameter(double v) { {IfcWrite::IfcWriteArgume
 double Ifc2x3::IfcTendon::CrossSectionArea() const {  double v = *data_->getArgument(11); return v; }
 void Ifc2x3::IfcTendon::setCrossSectionArea(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< double > Ifc2x3::IfcTendon::TensionForce() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc2x3::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc2x3::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc2x3::IfcTendon::PreStress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc2x3::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc2x3::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc2x3::IfcTendon::FrictionCoefficient() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc2x3::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc2x3::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc2x3::IfcTendon::AnchorageSlip() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc2x3::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc2x3::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc2x3::IfcTendon::MinCurvatureRadius() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc2x3::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc2x3::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcTendon::declaration() const { return *IFC2X3_IfcTendon_type; }
@@ -16308,13 +16308,13 @@ Ifc2x3::IfcTextStyle::IfcTextStyle(boost::optional< std::string > v1_Name, ::Ifc
 
 // Function implementations for IfcTextStyleFontModel
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc2x3::IfcTextStyleFontModel::FontFamily() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcTextStyleFontModel::setFontFamily(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcTextStyleFontModel::setFontFamily(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTextStyleFontModel::FontStyle() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTextStyleFontModel::FontVariant() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTextStyleFontModel::FontWeight() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc2x3::IfcSizeSelect* Ifc2x3::IfcTextStyleFontModel::FontSize() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc2x3::IfcSizeSelect>(true); }
 void Ifc2x3::IfcTextStyleFontModel::setFontSize(::Ifc2x3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -16340,15 +16340,15 @@ Ifc2x3::IfcTextStyleForDefinedFont::IfcTextStyleForDefinedFont(::Ifc2x3::IfcColo
 ::Ifc2x3::IfcSizeSelect* Ifc2x3::IfcTextStyleTextModel::TextIndent() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc2x3::IfcSizeSelect>(true); }
 void Ifc2x3::IfcTextStyleTextModel::setTextIndent(::Ifc2x3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTextStyleTextModel::TextAlign() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTextStyleTextModel::TextDecoration() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcSizeSelect* Ifc2x3::IfcTextStyleTextModel::LetterSpacing() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc2x3::IfcSizeSelect>(true); }
 void Ifc2x3::IfcTextStyleTextModel::setLetterSpacing(::Ifc2x3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc2x3::IfcSizeSelect* Ifc2x3::IfcTextStyleTextModel::WordSpacing() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc2x3::IfcSizeSelect>(true); }
 void Ifc2x3::IfcTextStyleTextModel::setWordSpacing(::Ifc2x3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTextStyleTextModel::TextTransform() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc2x3::IfcSizeSelect* Ifc2x3::IfcTextStyleTextModel::LineHeight() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc2x3::IfcSizeSelect>(true); }
 void Ifc2x3::IfcTextStyleTextModel::setLineHeight(::Ifc2x3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -16360,13 +16360,13 @@ Ifc2x3::IfcTextStyleTextModel::IfcTextStyleTextModel(::Ifc2x3::IfcSizeSelect* v1
 
 // Function implementations for IfcTextStyleWithBoxCharacteristics
 boost::optional< double > Ifc2x3::IfcTextStyleWithBoxCharacteristics::BoxHeight() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc2x3::IfcTextStyleWithBoxCharacteristics::setBoxHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc2x3::IfcTextStyleWithBoxCharacteristics::setBoxHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< double > Ifc2x3::IfcTextStyleWithBoxCharacteristics::BoxWidth() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcTextStyleWithBoxCharacteristics::setBoxWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcTextStyleWithBoxCharacteristics::setBoxWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcTextStyleWithBoxCharacteristics::BoxSlantAngle() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcTextStyleWithBoxCharacteristics::setBoxSlantAngle(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcTextStyleWithBoxCharacteristics::setBoxSlantAngle(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcTextStyleWithBoxCharacteristics::BoxRotateAngle() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcTextStyleWithBoxCharacteristics::setBoxRotateAngle(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcTextStyleWithBoxCharacteristics::setBoxRotateAngle(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc2x3::IfcSizeSelect* Ifc2x3::IfcTextStyleWithBoxCharacteristics::CharacterSpacing() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc2x3::IfcSizeSelect>(true); }
 void Ifc2x3::IfcTextStyleWithBoxCharacteristics::setCharacterSpacing(::Ifc2x3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -16419,13 +16419,13 @@ Ifc2x3::IfcTextureVertex::IfcTextureVertex(std::vector< double > /*[2:2]*/ v1_Co
 
 // Function implementations for IfcThermalMaterialProperties
 boost::optional< double > Ifc2x3::IfcThermalMaterialProperties::SpecificHeatCapacity() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcThermalMaterialProperties::setSpecificHeatCapacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcThermalMaterialProperties::setSpecificHeatCapacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcThermalMaterialProperties::BoilingPoint() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcThermalMaterialProperties::setBoilingPoint(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcThermalMaterialProperties::setBoilingPoint(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcThermalMaterialProperties::FreezingPoint() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcThermalMaterialProperties::setFreezingPoint(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcThermalMaterialProperties::setFreezingPoint(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcThermalMaterialProperties::ThermalConductivity() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcThermalMaterialProperties::setThermalConductivity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcThermalMaterialProperties::setThermalConductivity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcThermalMaterialProperties::declaration() const { return *IFC2X3_IfcThermalMaterialProperties_type; }
@@ -16437,7 +16437,7 @@ Ifc2x3::IfcThermalMaterialProperties::IfcThermalMaterialProperties(::Ifc2x3::Ifc
 std::string Ifc2x3::IfcTimeSeries::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc2x3::IfcTimeSeries::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTimeSeries::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcTimeSeries::StartTime() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
 void Ifc2x3::IfcTimeSeries::setStartTime(::Ifc2x3::IfcDateTimeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcTimeSeries::EndTime() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
@@ -16447,7 +16447,7 @@ void Ifc2x3::IfcTimeSeries::setTimeSeriesDataType(::Ifc2x3::IfcTimeSeriesDataTyp
 ::Ifc2x3::IfcDataOriginEnum::Value Ifc2x3::IfcTimeSeries::DataOrigin() const {  return ::Ifc2x3::IfcDataOriginEnum::FromString(*data_->getArgument(5)); }
 void Ifc2x3::IfcTimeSeries::setDataOrigin(::Ifc2x3::IfcDataOriginEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcDataOriginEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTimeSeries::UserDefinedDataOrigin() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc2x3::IfcUnit* Ifc2x3::IfcTimeSeries::Unit() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc2x3::IfcUnit>(true); }
 void Ifc2x3::IfcTimeSeries::setUnit(::Ifc2x3::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 
@@ -16472,7 +16472,7 @@ Ifc2x3::IfcTimeSeriesReferenceRelationship::IfcTimeSeriesReferenceRelationship(:
 
 // Function implementations for IfcTimeSeriesSchedule
 boost::optional< aggregate_of_instance::ptr > Ifc2x3::IfcTimeSeriesSchedule::ApplicableDates() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcTimeSeriesSchedule::setApplicableDates(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcTimeSeriesSchedule::setApplicableDates(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc2x3::IfcTimeSeriesScheduleTypeEnum::Value Ifc2x3::IfcTimeSeriesSchedule::TimeSeriesScheduleType() const {  return ::Ifc2x3::IfcTimeSeriesScheduleTypeEnum::FromString(*data_->getArgument(6)); }
 void Ifc2x3::IfcTimeSeriesSchedule::setTimeSeriesScheduleType(::Ifc2x3::IfcTimeSeriesScheduleTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcTimeSeriesScheduleTypeEnum::ToString(v)));data_->setArgument(6,attr);} }
 ::Ifc2x3::IfcTimeSeries* Ifc2x3::IfcTimeSeriesSchedule::TimeSeries() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc2x3::IfcTimeSeries>(true); }
@@ -16522,11 +16522,11 @@ Ifc2x3::IfcTransformerType::IfcTransformerType(std::string v1_GlobalId, ::Ifc2x3
 
 // Function implementations for IfcTransportElement
 boost::optional< ::Ifc2x3::IfcTransportElementTypeEnum::Value > Ifc2x3::IfcTransportElement::OperationType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc2x3::IfcTransportElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc2x3::IfcTransportElement::setOperationType(boost::optional< ::Ifc2x3::IfcTransportElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcTransportElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc2x3::IfcTransportElement::setOperationType(boost::optional< ::Ifc2x3::IfcTransportElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcTransportElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcTransportElement::CapacityByWeight() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcTransportElement::setCapacityByWeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcTransportElement::setCapacityByWeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcTransportElement::CapacityByNumber() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcTransportElement::setCapacityByNumber(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcTransportElement::setCapacityByNumber(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcTransportElement::declaration() const { return *IFC2X3_IfcTransportElement_type; }
@@ -16600,9 +16600,9 @@ Ifc2x3::IfcTwoDirectionRepeatFactor::IfcTwoDirectionRepeatFactor(::Ifc2x3::IfcVe
 
 // Function implementations for IfcTypeObject
 boost::optional< std::string > Ifc2x3::IfcTypeObject::ApplicableOccurrence() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcPropertySetDefinition >::ptr > Ifc2x3::IfcTypeObject::HasPropertySets() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc2x3::IfcPropertySetDefinition >(); }
-void Ifc2x3::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc2x3::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(5,attr);} }
+void Ifc2x3::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc2x3::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(5,attr);} }
 
 ::Ifc2x3::IfcRelDefinesByType::list::ptr Ifc2x3::IfcTypeObject::ObjectTypeOf() const { return data_->getInverse(IFC2X3_IfcRelDefinesByType_type, 5)->as<IfcRelDefinesByType>(); }
 
@@ -16613,9 +16613,9 @@ Ifc2x3::IfcTypeObject::IfcTypeObject(std::string v1_GlobalId, ::Ifc2x3::IfcOwner
 
 // Function implementations for IfcTypeProduct
 boost::optional< aggregate_of< ::Ifc2x3::IfcRepresentationMap >::ptr > Ifc2x3::IfcTypeProduct::RepresentationMaps() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc2x3::IfcRepresentationMap >(); }
-void Ifc2x3::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc2x3::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc2x3::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc2x3::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc2x3::IfcTypeProduct::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcTypeProduct::declaration() const { return *IFC2X3_IfcTypeProduct_type; }
@@ -16633,13 +16633,13 @@ void Ifc2x3::IfcUShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc2x3::IfcUShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc2x3::IfcUShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcUShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcUShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcUShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcUShapeProfileDef::CentreOfGravityInX() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcUShapeProfileDef::setCentreOfGravityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcUShapeProfileDef::setCentreOfGravityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcUShapeProfileDef::declaration() const { return *IFC2X3_IfcUShapeProfileDef_type; }
@@ -16797,19 +16797,19 @@ Ifc2x3::IfcWasteTerminalType::IfcWasteTerminalType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcWaterProperties
 boost::optional< bool > Ifc2x3::IfcWaterProperties::IsPotable() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc2x3::IfcWaterProperties::setIsPotable(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc2x3::IfcWaterProperties::setIsPotable(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc2x3::IfcWaterProperties::Hardness() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc2x3::IfcWaterProperties::setHardness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc2x3::IfcWaterProperties::setHardness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc2x3::IfcWaterProperties::AlkalinityConcentration() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc2x3::IfcWaterProperties::setAlkalinityConcentration(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc2x3::IfcWaterProperties::setAlkalinityConcentration(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc2x3::IfcWaterProperties::AcidityConcentration() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcWaterProperties::setAcidityConcentration(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcWaterProperties::setAcidityConcentration(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcWaterProperties::ImpuritiesContent() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcWaterProperties::setImpuritiesContent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcWaterProperties::setImpuritiesContent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcWaterProperties::PHLevel() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcWaterProperties::setPHLevel(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcWaterProperties::setPHLevel(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcWaterProperties::DissolvedSolidsContent() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcWaterProperties::setDissolvedSolidsContent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcWaterProperties::setDissolvedSolidsContent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcWaterProperties::declaration() const { return *IFC2X3_IfcWaterProperties_type; }
@@ -16819,9 +16819,9 @@ Ifc2x3::IfcWaterProperties::IfcWaterProperties(::Ifc2x3::IfcMaterial* v1_Materia
 
 // Function implementations for IfcWindow
 boost::optional< double > Ifc2x3::IfcWindow::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcWindow::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcWindow::declaration() const { return *IFC2X3_IfcWindow_type; }
@@ -16831,21 +16831,21 @@ Ifc2x3::IfcWindow::IfcWindow(std::string v1_GlobalId, ::Ifc2x3::IfcOwnerHistory*
 
 // Function implementations for IfcWindowLiningProperties
 boost::optional< double > Ifc2x3::IfcWindowLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc2x3::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc2x3::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc2x3::IfcWindowLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc2x3::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc2x3::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcWindowLiningProperties::TransomThickness() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcWindowLiningProperties::MullionThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcWindowLiningProperties::FirstTransomOffset() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcWindowLiningProperties::SecondTransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcWindowLiningProperties::FirstMullionOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc2x3::IfcWindowLiningProperties::SecondMullionOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc2x3::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc2x3::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 ::Ifc2x3::IfcShapeAspect* Ifc2x3::IfcWindowLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(12)))->as<::Ifc2x3::IfcShapeAspect>(true); }
 void Ifc2x3::IfcWindowLiningProperties::setShapeAspectStyle(::Ifc2x3::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(12,attr);} }
 
@@ -16861,9 +16861,9 @@ void Ifc2x3::IfcWindowPanelProperties::setOperationType(::Ifc2x3::IfcWindowPanel
 ::Ifc2x3::IfcWindowPanelPositionEnum::Value Ifc2x3::IfcWindowPanelProperties::PanelPosition() const {  return ::Ifc2x3::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc2x3::IfcWindowPanelProperties::setPanelPosition(::Ifc2x3::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc2x3::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc2x3::IfcWindowPanelProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc2x3::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc2x3::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcWindowPanelProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc2x3::IfcShapeAspect* Ifc2x3::IfcWindowPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc2x3::IfcShapeAspect>(true); }
 void Ifc2x3::IfcWindowPanelProperties::setShapeAspectStyle(::Ifc2x3::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -16895,21 +16895,21 @@ void Ifc2x3::IfcWorkControl::setIdentifier(std::string v) { {IfcWrite::IfcWriteA
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcWorkControl::CreationDate() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
 void Ifc2x3::IfcWorkControl::setCreationDate(::Ifc2x3::IfcDateTimeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc2x3::IfcPerson >::ptr > Ifc2x3::IfcWorkControl::Creators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc2x3::IfcPerson >(); }
-void Ifc2x3::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc2x3::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc2x3::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc2x3::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc2x3::IfcWorkControl::Purpose() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc2x3::IfcWorkControl::Duration() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc2x3::IfcWorkControl::setDuration(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc2x3::IfcWorkControl::setDuration(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc2x3::IfcWorkControl::TotalFloat() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc2x3::IfcWorkControl::setTotalFloat(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc2x3::IfcWorkControl::setTotalFloat(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcWorkControl::StartTime() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
 void Ifc2x3::IfcWorkControl::setStartTime(::Ifc2x3::IfcDateTimeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 ::Ifc2x3::IfcDateTimeSelect* Ifc2x3::IfcWorkControl::FinishTime() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(12)))->as<::Ifc2x3::IfcDateTimeSelect>(true); }
 void Ifc2x3::IfcWorkControl::setFinishTime(::Ifc2x3::IfcDateTimeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(12,attr);} }
 boost::optional< ::Ifc2x3::IfcWorkControlTypeEnum::Value > Ifc2x3::IfcWorkControl::WorkControlType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc2x3::IfcWorkControlTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc2x3::IfcWorkControl::setWorkControlType(boost::optional< ::Ifc2x3::IfcWorkControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcWorkControlTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc2x3::IfcWorkControl::setWorkControlType(boost::optional< ::Ifc2x3::IfcWorkControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc2x3::IfcWorkControlTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc2x3::IfcWorkControl::UserDefinedControlType() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc2x3::IfcWorkControl::setUserDefinedControlType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc2x3::IfcWorkControl::setUserDefinedControlType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcWorkControl::declaration() const { return *IFC2X3_IfcWorkControl_type; }
@@ -16943,9 +16943,9 @@ void Ifc2x3::IfcZShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc2x3::IfcZShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc2x3::IfcZShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc2x3::IfcZShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc2x3::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc2x3::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc2x3::IfcZShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc2x3::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc2x3::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc2x3::IfcZShapeProfileDef::declaration() const { return *IFC2X3_IfcZShapeProfileDef_type; }
diff --git a/src/ifcparse/Ifc4.cpp b/src/ifcparse/Ifc4.cpp
index 32576d5748..3f0b878a59 100644
--- a/src/ifcparse/Ifc4.cpp
+++ b/src/ifcparse/Ifc4.cpp
@@ -11123,11 +11123,11 @@ Ifc4::IfcWarpingMomentMeasure::operator double() const { return *data_->getArgum
 
 // Function implementations for IfcActionRequest
 boost::optional< ::Ifc4::IfcActionRequestTypeEnum::Value > Ifc4::IfcActionRequest::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4::IfcActionRequestTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcActionRequestTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcActionRequestTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcActionRequest::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcActionRequest::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcActionRequest::declaration() const { return *IFC4_IfcActionRequest_type; }
@@ -11150,9 +11150,9 @@ Ifc4::IfcActor::IfcActor(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Ow
 ::Ifc4::IfcRoleEnum::Value Ifc4::IfcActorRole::Role() const {  return ::Ifc4::IfcRoleEnum::FromString(*data_->getArgument(0)); }
 void Ifc4::IfcActorRole::setRole(::Ifc4::IfcRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcRoleEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcActorRole::UserDefinedRole() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcActorRole::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4::IfcExternalReferenceRelationship::list::ptr Ifc4::IfcActorRole::HasExternalReference() const { return data_->getInverse(IFC4_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -11163,7 +11163,7 @@ Ifc4::IfcActorRole::IfcActorRole(::Ifc4::IfcRoleEnum::Value v1_Role, boost::opti
 
 // Function implementations for IfcActuator
 boost::optional< ::Ifc4::IfcActuatorTypeEnum::Value > Ifc4::IfcActuator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcActuatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcActuator::setPredefinedType(boost::optional< ::Ifc4::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcActuatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcActuator::setPredefinedType(boost::optional< ::Ifc4::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcActuatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcActuator::declaration() const { return *IFC4_IfcActuator_type; }
@@ -11183,11 +11183,11 @@ Ifc4::IfcActuatorType::IfcActuatorType(std::string v1_GlobalId, ::Ifc4::IfcOwner
 
 // Function implementations for IfcAddress
 boost::optional< ::Ifc4::IfcAddressTypeEnum::Value > Ifc4::IfcAddress::Purpose() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } return ::Ifc4::IfcAddressTypeEnum::FromString(*data_->getArgument(0)); }
-void Ifc4::IfcAddress::setPurpose(boost::optional< ::Ifc4::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAddressTypeEnum::ToString(*v)));data_->setArgument(0,attr);} }
+void Ifc4::IfcAddress::setPurpose(boost::optional< ::Ifc4::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAddressTypeEnum::ToString(*v)));}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcAddress::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcAddress::UserDefinedPurpose() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4::IfcPerson::list::ptr Ifc4::IfcAddress::OfPerson() const { return data_->getInverse(IFC4_IfcPerson_type, 7)->as<IfcPerson>(); }
 ::Ifc4::IfcOrganization::list::ptr Ifc4::IfcAddress::OfOrganization() const { return data_->getInverse(IFC4_IfcOrganization_type, 4)->as<IfcOrganization>(); }
@@ -11225,7 +11225,7 @@ Ifc4::IfcAdvancedFace::IfcAdvancedFace(aggregate_of< ::Ifc4::IfcFaceBound >::ptr
 
 // Function implementations for IfcAirTerminal
 boost::optional< ::Ifc4::IfcAirTerminalTypeEnum::Value > Ifc4::IfcAirTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcAirTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAirTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAirTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcAirTerminal::declaration() const { return *IFC4_IfcAirTerminal_type; }
@@ -11235,7 +11235,7 @@ Ifc4::IfcAirTerminal::IfcAirTerminal(std::string v1_GlobalId, ::Ifc4::IfcOwnerHi
 
 // Function implementations for IfcAirTerminalBox
 boost::optional< ::Ifc4::IfcAirTerminalBoxTypeEnum::Value > Ifc4::IfcAirTerminalBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcAirTerminalBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAirTerminalBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAirTerminalBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcAirTerminalBox::declaration() const { return *IFC4_IfcAirTerminalBox_type; }
@@ -11265,7 +11265,7 @@ Ifc4::IfcAirTerminalType::IfcAirTerminalType(std::string v1_GlobalId, ::Ifc4::If
 
 // Function implementations for IfcAirToAirHeatRecovery
 boost::optional< ::Ifc4::IfcAirToAirHeatRecoveryTypeEnum::Value > Ifc4::IfcAirToAirHeatRecovery::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcAirToAirHeatRecoveryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcAirToAirHeatRecovery::declaration() const { return *IFC4_IfcAirToAirHeatRecovery_type; }
@@ -11285,7 +11285,7 @@ Ifc4::IfcAirToAirHeatRecoveryType::IfcAirToAirHeatRecoveryType(std::string v1_Gl
 
 // Function implementations for IfcAlarm
 boost::optional< ::Ifc4::IfcAlarmTypeEnum::Value > Ifc4::IfcAlarm::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcAlarmTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAlarmTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAlarmTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcAlarm::declaration() const { return *IFC4_IfcAlarm_type; }
@@ -11316,7 +11316,7 @@ Ifc4::IfcAnnotation::IfcAnnotation(std::string v1_GlobalId, ::Ifc4::IfcOwnerHist
 ::Ifc4::IfcCurve* Ifc4::IfcAnnotationFillArea::OuterBoundary() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4::IfcCurve>(true); }
 void Ifc4::IfcAnnotationFillArea::setOuterBoundary(::Ifc4::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcCurve >::ptr > Ifc4::IfcAnnotationFillArea::InnerBoundaries() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4::IfcCurve >(); }
-void Ifc4::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcAnnotationFillArea::declaration() const { return *IFC4_IfcAnnotationFillArea_type; }
@@ -11342,25 +11342,25 @@ Ifc4::IfcApplication::IfcApplication(::Ifc4::IfcOrganization* v1_ApplicationDeve
 
 // Function implementations for IfcAppliedValue
 boost::optional< std::string > Ifc4::IfcAppliedValue::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcAppliedValue::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4::IfcAppliedValueSelect* Ifc4::IfcAppliedValue::AppliedValue() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4::IfcAppliedValueSelect>(true); }
 void Ifc4::IfcAppliedValue::setAppliedValue(::Ifc4::IfcAppliedValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4::IfcMeasureWithUnit* Ifc4::IfcAppliedValue::UnitBasis() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcMeasureWithUnit>(true); }
 void Ifc4::IfcAppliedValue::setUnitBasis(::Ifc4::IfcMeasureWithUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcAppliedValue::ApplicableDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcAppliedValue::FixedUntilDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcAppliedValue::Category() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcAppliedValue::Condition() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4::IfcArithmeticOperatorEnum::Value > Ifc4::IfcAppliedValue::ArithmeticOperator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcArithmeticOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcArithmeticOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcArithmeticOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcAppliedValue >::ptr > Ifc4::IfcAppliedValue::Components() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4::IfcAppliedValue >(); }
-void Ifc4::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 
 ::Ifc4::IfcExternalReferenceRelationship::list::ptr Ifc4::IfcAppliedValue::HasExternalReference() const { return data_->getInverse(IFC4_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -11371,19 +11371,19 @@ Ifc4::IfcAppliedValue::IfcAppliedValue(boost::optional< std::string > v1_Name, b
 
 // Function implementations for IfcApproval
 boost::optional< std::string > Ifc4::IfcApproval::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcApproval::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcApproval::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4::IfcApproval::TimeOfApproval() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcApproval::Status() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcApproval::Level() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcApproval::Qualifier() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4::IfcActorSelect* Ifc4::IfcApproval::RequestingApproval() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4::IfcActorSelect>(true); }
 void Ifc4::IfcApproval::setRequestingApproval(::Ifc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4::IfcActorSelect* Ifc4::IfcApproval::GivingApproval() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4::IfcActorSelect>(true); }
@@ -11444,7 +11444,7 @@ Ifc4::IfcArbitraryProfileDefWithVoids::IfcArbitraryProfileDefWithVoids(::Ifc4::I
 
 // Function implementations for IfcAsset
 boost::optional< std::string > Ifc4::IfcAsset::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4::IfcCostValue* Ifc4::IfcAsset::OriginalValue() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcCostValue>(true); }
 void Ifc4::IfcAsset::setOriginalValue(::Ifc4::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 ::Ifc4::IfcCostValue* Ifc4::IfcAsset::CurrentValue() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4::IfcCostValue>(true); }
@@ -11458,7 +11458,7 @@ void Ifc4::IfcAsset::setUser(::Ifc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArg
 ::Ifc4::IfcPerson* Ifc4::IfcAsset::ResponsiblePerson() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4::IfcPerson>(true); }
 void Ifc4::IfcAsset::setResponsiblePerson(::Ifc4::IfcPerson* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4::IfcAsset::IncorporationDate() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4::IfcCostValue* Ifc4::IfcAsset::DepreciatedValue() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4::IfcCostValue>(true); }
 void Ifc4::IfcAsset::setDepreciatedValue(::Ifc4::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -11478,21 +11478,21 @@ void Ifc4::IfcAsymmetricIShapeProfileDef::setWebThickness(double v) { {IfcWrite:
 double Ifc4::IfcAsymmetricIShapeProfileDef::BottomFlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcAsymmetricIShapeProfileDef::BottomFlangeFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 double Ifc4::IfcAsymmetricIShapeProfileDef::TopFlangeWidth() const {  double v = *data_->getArgument(8); return v; }
 void Ifc4::IfcAsymmetricIShapeProfileDef::setTopFlangeWidth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4::IfcAsymmetricIShapeProfileDef::TopFlangeThickness() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcAsymmetricIShapeProfileDef::TopFlangeFilletRadius() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcAsymmetricIShapeProfileDef::BottomFlangeEdgeRadius() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4::IfcAsymmetricIShapeProfileDef::BottomFlangeSlope() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4::IfcAsymmetricIShapeProfileDef::TopFlangeEdgeRadius() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4::IfcAsymmetricIShapeProfileDef::TopFlangeSlope() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcAsymmetricIShapeProfileDef::declaration() const { return *IFC4_IfcAsymmetricIShapeProfileDef_type; }
@@ -11502,7 +11502,7 @@ Ifc4::IfcAsymmetricIShapeProfileDef::IfcAsymmetricIShapeProfileDef(::Ifc4::IfcPr
 
 // Function implementations for IfcAudioVisualAppliance
 boost::optional< ::Ifc4::IfcAudioVisualApplianceTypeEnum::Value > Ifc4::IfcAudioVisualAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcAudioVisualApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAudioVisualApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAudioVisualApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcAudioVisualAppliance::declaration() const { return *IFC4_IfcAudioVisualAppliance_type; }
@@ -11626,7 +11626,7 @@ Ifc4::IfcBSplineSurfaceWithKnots::IfcBSplineSurfaceWithKnots(int v1_UDegree, int
 
 // Function implementations for IfcBeam
 boost::optional< ::Ifc4::IfcBeamTypeEnum::Value > Ifc4::IfcBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcBeam::setPredefinedType(boost::optional< ::Ifc4::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcBeam::setPredefinedType(boost::optional< ::Ifc4::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcBeam::declaration() const { return *IFC4_IfcBeam_type; }
@@ -11680,7 +11680,7 @@ Ifc4::IfcBlock::IfcBlock(::Ifc4::IfcAxis2Placement3D* v1_Position, double v2_XLe
 
 // Function implementations for IfcBoiler
 boost::optional< ::Ifc4::IfcBoilerTypeEnum::Value > Ifc4::IfcBoiler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcBoilerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBoilerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBoilerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcBoiler::declaration() const { return *IFC4_IfcBoiler_type; }
@@ -11722,7 +11722,7 @@ Ifc4::IfcBooleanResult::IfcBooleanResult(::Ifc4::IfcBooleanOperator::Value v1_Op
 
 // Function implementations for IfcBoundaryCondition
 boost::optional< std::string > Ifc4::IfcBoundaryCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcBoundaryCondition::declaration() const { return *IFC4_IfcBoundaryCondition_type; }
@@ -11846,9 +11846,9 @@ Ifc4::IfcBoxedHalfSpace::IfcBoxedHalfSpace(::Ifc4::IfcSurface* v1_BaseSurface, b
 
 // Function implementations for IfcBuilding
 boost::optional< double > Ifc4::IfcBuilding::ElevationOfRefHeight() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcBuilding::ElevationOfTerrain() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4::IfcPostalAddress* Ifc4::IfcBuilding::BuildingAddress() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4::IfcPostalAddress>(true); }
 void Ifc4::IfcBuilding::setBuildingAddress(::Ifc4::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 
@@ -11868,7 +11868,7 @@ Ifc4::IfcBuildingElement::IfcBuildingElement(std::string v1_GlobalId, ::Ifc4::If
 
 // Function implementations for IfcBuildingElementPart
 boost::optional< ::Ifc4::IfcBuildingElementPartTypeEnum::Value > Ifc4::IfcBuildingElementPart::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcBuildingElementPartTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBuildingElementPartTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBuildingElementPartTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcBuildingElementPart::declaration() const { return *IFC4_IfcBuildingElementPart_type; }
@@ -11888,7 +11888,7 @@ Ifc4::IfcBuildingElementPartType::IfcBuildingElementPartType(std::string v1_Glob
 
 // Function implementations for IfcBuildingElementProxy
 boost::optional< ::Ifc4::IfcBuildingElementProxyTypeEnum::Value > Ifc4::IfcBuildingElementProxy::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcBuildingElementProxyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBuildingElementProxyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBuildingElementProxyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcBuildingElementProxy::declaration() const { return *IFC4_IfcBuildingElementProxy_type; }
@@ -11916,7 +11916,7 @@ Ifc4::IfcBuildingElementType::IfcBuildingElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcBuildingStorey
 boost::optional< double > Ifc4::IfcBuildingStorey::Elevation() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcBuildingStorey::declaration() const { return *IFC4_IfcBuildingStorey_type; }
@@ -11926,9 +11926,9 @@ Ifc4::IfcBuildingStorey::IfcBuildingStorey(std::string v1_GlobalId, ::Ifc4::IfcO
 
 // Function implementations for IfcBuildingSystem
 boost::optional< ::Ifc4::IfcBuildingSystemTypeEnum::Value > Ifc4::IfcBuildingSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4::IfcBuildingSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBuildingSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBuildingSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcBuildingSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcBuildingSystem::declaration() const { return *IFC4_IfcBuildingSystem_type; }
@@ -11938,7 +11938,7 @@ Ifc4::IfcBuildingSystem::IfcBuildingSystem(std::string v1_GlobalId, ::Ifc4::IfcO
 
 // Function implementations for IfcBurner
 boost::optional< ::Ifc4::IfcBurnerTypeEnum::Value > Ifc4::IfcBurner::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcBurnerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcBurner::setPredefinedType(boost::optional< ::Ifc4::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBurnerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcBurner::setPredefinedType(boost::optional< ::Ifc4::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcBurnerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcBurner::declaration() const { return *IFC4_IfcBurner_type; }
@@ -11966,7 +11966,7 @@ void Ifc4::IfcCShapeProfileDef::setWallThickness(double v) { {IfcWrite::IfcWrite
 double Ifc4::IfcCShapeProfileDef::Girth() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4::IfcCShapeProfileDef::setGirth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcCShapeProfileDef::InternalFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCShapeProfileDef::declaration() const { return *IFC4_IfcCShapeProfileDef_type; }
@@ -11976,7 +11976,7 @@ Ifc4::IfcCShapeProfileDef::IfcCShapeProfileDef(::Ifc4::IfcProfileTypeEnum::Value
 
 // Function implementations for IfcCableCarrierFitting
 boost::optional< ::Ifc4::IfcCableCarrierFittingTypeEnum::Value > Ifc4::IfcCableCarrierFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCableCarrierFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCableCarrierFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCableCarrierFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCableCarrierFitting::declaration() const { return *IFC4_IfcCableCarrierFitting_type; }
@@ -11996,7 +11996,7 @@ Ifc4::IfcCableCarrierFittingType::IfcCableCarrierFittingType(std::string v1_Glob
 
 // Function implementations for IfcCableCarrierSegment
 boost::optional< ::Ifc4::IfcCableCarrierSegmentTypeEnum::Value > Ifc4::IfcCableCarrierSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCableCarrierSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCableCarrierSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCableCarrierSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCableCarrierSegment::declaration() const { return *IFC4_IfcCableCarrierSegment_type; }
@@ -12016,7 +12016,7 @@ Ifc4::IfcCableCarrierSegmentType::IfcCableCarrierSegmentType(std::string v1_Glob
 
 // Function implementations for IfcCableFitting
 boost::optional< ::Ifc4::IfcCableFittingTypeEnum::Value > Ifc4::IfcCableFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCableFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCableFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCableFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCableFitting::declaration() const { return *IFC4_IfcCableFitting_type; }
@@ -12036,7 +12036,7 @@ Ifc4::IfcCableFittingType::IfcCableFittingType(std::string v1_GlobalId, ::Ifc4::
 
 // Function implementations for IfcCableSegment
 boost::optional< ::Ifc4::IfcCableSegmentTypeEnum::Value > Ifc4::IfcCableSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCableSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCableSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCableSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCableSegment::declaration() const { return *IFC4_IfcCableSegment_type; }
@@ -12100,7 +12100,7 @@ void Ifc4::IfcCartesianTransformationOperator::setAxis2(::Ifc4::IfcDirection* v)
 ::Ifc4::IfcCartesianPoint* Ifc4::IfcCartesianTransformationOperator::LocalOrigin() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4::IfcCartesianPoint>(true); }
 void Ifc4::IfcCartesianTransformationOperator::setLocalOrigin(::Ifc4::IfcCartesianPoint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcCartesianTransformationOperator::Scale() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCartesianTransformationOperator::declaration() const { return *IFC4_IfcCartesianTransformationOperator_type; }
@@ -12118,7 +12118,7 @@ Ifc4::IfcCartesianTransformationOperator2D::IfcCartesianTransformationOperator2D
 
 // Function implementations for IfcCartesianTransformationOperator2DnonUniform
 boost::optional< double > Ifc4::IfcCartesianTransformationOperator2DnonUniform::Scale2() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCartesianTransformationOperator2DnonUniform::declaration() const { return *IFC4_IfcCartesianTransformationOperator2DnonUniform_type; }
@@ -12138,9 +12138,9 @@ Ifc4::IfcCartesianTransformationOperator3D::IfcCartesianTransformationOperator3D
 
 // Function implementations for IfcCartesianTransformationOperator3DnonUniform
 boost::optional< double > Ifc4::IfcCartesianTransformationOperator3DnonUniform::Scale2() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcCartesianTransformationOperator3DnonUniform::Scale3() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCartesianTransformationOperator3DnonUniform::declaration() const { return *IFC4_IfcCartesianTransformationOperator3DnonUniform_type; }
@@ -12160,7 +12160,7 @@ Ifc4::IfcCenterLineProfileDef::IfcCenterLineProfileDef(::Ifc4::IfcProfileTypeEnu
 
 // Function implementations for IfcChiller
 boost::optional< ::Ifc4::IfcChillerTypeEnum::Value > Ifc4::IfcChiller::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcChillerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcChiller::setPredefinedType(boost::optional< ::Ifc4::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcChillerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcChiller::setPredefinedType(boost::optional< ::Ifc4::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcChillerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcChiller::declaration() const { return *IFC4_IfcChiller_type; }
@@ -12180,7 +12180,7 @@ Ifc4::IfcChillerType::IfcChillerType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHi
 
 // Function implementations for IfcChimney
 boost::optional< ::Ifc4::IfcChimneyTypeEnum::Value > Ifc4::IfcChimney::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcChimneyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcChimney::setPredefinedType(boost::optional< ::Ifc4::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcChimneyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcChimney::setPredefinedType(boost::optional< ::Ifc4::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcChimneyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcChimney::declaration() const { return *IFC4_IfcChimney_type; }
@@ -12246,19 +12246,19 @@ Ifc4::IfcCivilElementType::IfcCivilElementType(std::string v1_GlobalId, ::Ifc4::
 
 // Function implementations for IfcClassification
 boost::optional< std::string > Ifc4::IfcClassification::Source() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcClassification::Edition() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcClassification::EditionDate() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::string Ifc4::IfcClassification::Name() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4::IfcClassification::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcClassification::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcClassification::Location() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4::IfcClassification::ReferenceTokens() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4::IfcRelAssociatesClassification::list::ptr Ifc4::IfcClassification::ClassificationForObjects() const { return data_->getInverse(IFC4_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4::IfcClassificationReference::list::ptr Ifc4::IfcClassification::HasReferences() const { return data_->getInverse(IFC4_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -12272,9 +12272,9 @@ Ifc4::IfcClassification::IfcClassification(boost::optional< std::string > v1_Sou
 ::Ifc4::IfcClassificationReferenceSelect* Ifc4::IfcClassificationReference::ReferencedSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcClassificationReferenceSelect>(true); }
 void Ifc4::IfcClassificationReference::setReferencedSource(::Ifc4::IfcClassificationReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcClassificationReference::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcClassificationReference::Sort() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4::IfcRelAssociatesClassification::list::ptr Ifc4::IfcClassificationReference::ClassificationRefForObjects() const { return data_->getInverse(IFC4_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4::IfcClassificationReference::list::ptr Ifc4::IfcClassificationReference::HasReferences() const { return data_->getInverse(IFC4_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -12294,7 +12294,7 @@ Ifc4::IfcClosedShell::IfcClosedShell(aggregate_of< ::Ifc4::IfcFace >::ptr v1_Cfs
 
 // Function implementations for IfcCoil
 boost::optional< ::Ifc4::IfcCoilTypeEnum::Value > Ifc4::IfcCoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCoil::setPredefinedType(boost::optional< ::Ifc4::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCoil::setPredefinedType(boost::optional< ::Ifc4::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCoil::declaration() const { return *IFC4_IfcCoil_type; }
@@ -12338,7 +12338,7 @@ Ifc4::IfcColourRgbList::IfcColourRgbList(std::vector< std::vector< double > > v1
 
 // Function implementations for IfcColourSpecification
 boost::optional< std::string > Ifc4::IfcColourSpecification::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcColourSpecification::declaration() const { return *IFC4_IfcColourSpecification_type; }
@@ -12348,7 +12348,7 @@ Ifc4::IfcColourSpecification::IfcColourSpecification(boost::optional< std::strin
 
 // Function implementations for IfcColumn
 boost::optional< ::Ifc4::IfcColumnTypeEnum::Value > Ifc4::IfcColumn::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcColumnTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcColumn::setPredefinedType(boost::optional< ::Ifc4::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcColumnTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcColumn::setPredefinedType(boost::optional< ::Ifc4::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcColumnTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcColumn::declaration() const { return *IFC4_IfcColumn_type; }
@@ -12376,7 +12376,7 @@ Ifc4::IfcColumnType::IfcColumnType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHist
 
 // Function implementations for IfcCommunicationsAppliance
 boost::optional< ::Ifc4::IfcCommunicationsApplianceTypeEnum::Value > Ifc4::IfcCommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCommunicationsAppliance::declaration() const { return *IFC4_IfcCommunicationsAppliance_type; }
@@ -12408,11 +12408,11 @@ Ifc4::IfcComplexProperty::IfcComplexProperty(std::string v1_Name, boost::optiona
 
 // Function implementations for IfcComplexPropertyTemplate
 boost::optional< std::string > Ifc4::IfcComplexPropertyTemplate::UsageName() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4::IfcComplexPropertyTemplateTypeEnum::Value > Ifc4::IfcComplexPropertyTemplate::TemplateType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4::IfcComplexPropertyTemplateTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcPropertyTemplate >::ptr > Ifc4::IfcComplexPropertyTemplate::HasPropertyTemplates() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4::IfcPropertyTemplate >(); }
-void Ifc4::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcComplexPropertyTemplate::declaration() const { return *IFC4_IfcComplexPropertyTemplate_type; }
@@ -12459,7 +12459,7 @@ Ifc4::IfcCompositeCurveSegment::IfcCompositeCurveSegment(::Ifc4::IfcTransitionCo
 aggregate_of< ::Ifc4::IfcProfileDef >::ptr Ifc4::IfcCompositeProfileDef::Profiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4::IfcProfileDef >(); }
 void Ifc4::IfcCompositeProfileDef::setProfiles(aggregate_of< ::Ifc4::IfcProfileDef >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4::IfcCompositeProfileDef::Label() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCompositeProfileDef::declaration() const { return *IFC4_IfcCompositeProfileDef_type; }
@@ -12469,7 +12469,7 @@ Ifc4::IfcCompositeProfileDef::IfcCompositeProfileDef(::Ifc4::IfcProfileTypeEnum:
 
 // Function implementations for IfcCompressor
 boost::optional< ::Ifc4::IfcCompressorTypeEnum::Value > Ifc4::IfcCompressor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCompressorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCompressorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCompressorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCompressor::declaration() const { return *IFC4_IfcCompressor_type; }
@@ -12489,7 +12489,7 @@ Ifc4::IfcCompressorType::IfcCompressorType(std::string v1_GlobalId, ::Ifc4::IfcO
 
 // Function implementations for IfcCondenser
 boost::optional< ::Ifc4::IfcCondenserTypeEnum::Value > Ifc4::IfcCondenser::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCondenserTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCondenserTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCondenserTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCondenser::declaration() const { return *IFC4_IfcCondenser_type; }
@@ -12549,11 +12549,11 @@ Ifc4::IfcConnectionGeometry::IfcConnectionGeometry() : IfcUtil::IfcBaseEntity()
 
 // Function implementations for IfcConnectionPointEccentricity
 boost::optional< double > Ifc4::IfcConnectionPointEccentricity::EccentricityInX() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcConnectionPointEccentricity::EccentricityInY() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcConnectionPointEccentricity::EccentricityInZ() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcConnectionPointEccentricity::declaration() const { return *IFC4_IfcConnectionPointEccentricity_type; }
@@ -12601,17 +12601,17 @@ Ifc4::IfcConnectionVolumeGeometry::IfcConnectionVolumeGeometry(::Ifc4::IfcSolidO
 std::string Ifc4::IfcConstraint::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4::IfcConstraint::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcConstraint::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4::IfcConstraintEnum::Value Ifc4::IfcConstraint::ConstraintGrade() const {  return ::Ifc4::IfcConstraintEnum::FromString(*data_->getArgument(2)); }
 void Ifc4::IfcConstraint::setConstraintGrade(::Ifc4::IfcConstraintEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcConstraintEnum::ToString(v)));data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4::IfcConstraint::ConstraintSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4::IfcActorSelect* Ifc4::IfcConstraint::CreatingActor() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4::IfcActorSelect>(true); }
 void Ifc4::IfcConstraint::setCreatingActor(::Ifc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcConstraint::CreationTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcConstraint::UserDefinedGrade() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4::IfcExternalReferenceRelationship::list::ptr Ifc4::IfcConstraint::HasExternalReferences() const { return data_->getInverse(IFC4_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4::IfcResourceConstraintRelationship::list::ptr Ifc4::IfcConstraint::PropertiesForConstraint() const { return data_->getInverse(IFC4_IfcResourceConstraintRelationship_type, 2)->as<IfcResourceConstraintRelationship>(); }
@@ -12623,7 +12623,7 @@ Ifc4::IfcConstraint::IfcConstraint(std::string v1_Name, boost::optional< std::st
 
 // Function implementations for IfcConstructionEquipmentResource
 boost::optional< ::Ifc4::IfcConstructionEquipmentResourceTypeEnum::Value > Ifc4::IfcConstructionEquipmentResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcConstructionEquipmentResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcConstructionEquipmentResource::declaration() const { return *IFC4_IfcConstructionEquipmentResource_type; }
@@ -12643,7 +12643,7 @@ Ifc4::IfcConstructionEquipmentResourceType::IfcConstructionEquipmentResourceType
 
 // Function implementations for IfcConstructionMaterialResource
 boost::optional< ::Ifc4::IfcConstructionMaterialResourceTypeEnum::Value > Ifc4::IfcConstructionMaterialResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcConstructionMaterialResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcConstructionMaterialResource::declaration() const { return *IFC4_IfcConstructionMaterialResource_type; }
@@ -12663,7 +12663,7 @@ Ifc4::IfcConstructionMaterialResourceType::IfcConstructionMaterialResourceType(s
 
 // Function implementations for IfcConstructionProductResource
 boost::optional< ::Ifc4::IfcConstructionProductResourceTypeEnum::Value > Ifc4::IfcConstructionProductResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcConstructionProductResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcConstructionProductResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcConstructionProductResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcConstructionProductResource::declaration() const { return *IFC4_IfcConstructionProductResource_type; }
@@ -12685,7 +12685,7 @@ Ifc4::IfcConstructionProductResourceType::IfcConstructionProductResourceType(std
 ::Ifc4::IfcResourceTime* Ifc4::IfcConstructionResource::Usage() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4::IfcResourceTime>(true); }
 void Ifc4::IfcConstructionResource::setUsage(::Ifc4::IfcResourceTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcAppliedValue >::ptr > Ifc4::IfcConstructionResource::BaseCosts() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4::IfcAppliedValue >(); }
-void Ifc4::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4::IfcPhysicalQuantity* Ifc4::IfcConstructionResource::BaseQuantity() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4::IfcPhysicalQuantity>(true); }
 void Ifc4::IfcConstructionResource::setBaseQuantity(::Ifc4::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -12697,7 +12697,7 @@ Ifc4::IfcConstructionResource::IfcConstructionResource(std::string v1_GlobalId,
 
 // Function implementations for IfcConstructionResourceType
 boost::optional< aggregate_of< ::Ifc4::IfcAppliedValue >::ptr > Ifc4::IfcConstructionResourceType::BaseCosts() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4::IfcAppliedValue >(); }
-void Ifc4::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 ::Ifc4::IfcPhysicalQuantity* Ifc4::IfcConstructionResourceType::BaseQuantity() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4::IfcPhysicalQuantity>(true); }
 void Ifc4::IfcConstructionResourceType::setBaseQuantity(::Ifc4::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -12709,13 +12709,13 @@ Ifc4::IfcConstructionResourceType::IfcConstructionResourceType(std::string v1_Gl
 
 // Function implementations for IfcContext
 boost::optional< std::string > Ifc4::IfcContext::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcContext::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcContext::Phase() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcRepresentationContext >::ptr > Ifc4::IfcContext::RepresentationContexts() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4::IfcRepresentationContext >(); }
-void Ifc4::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 ::Ifc4::IfcUnitAssignment* Ifc4::IfcContext::UnitsInContext() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4::IfcUnitAssignment>(true); }
 void Ifc4::IfcContext::setUnitsInContext(::Ifc4::IfcUnitAssignment* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -12740,7 +12740,7 @@ Ifc4::IfcContextDependentUnit::IfcContextDependentUnit(::Ifc4::IfcDimensionalExp
 
 // Function implementations for IfcControl
 boost::optional< std::string > Ifc4::IfcControl::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4::IfcRelAssignsToControl::list::ptr Ifc4::IfcControl::Controls() const { return data_->getInverse(IFC4_IfcRelAssignsToControl_type, 6)->as<IfcRelAssignsToControl>(); }
 
@@ -12751,7 +12751,7 @@ Ifc4::IfcControl::IfcControl(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v
 
 // Function implementations for IfcController
 boost::optional< ::Ifc4::IfcControllerTypeEnum::Value > Ifc4::IfcController::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcControllerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcController::setPredefinedType(boost::optional< ::Ifc4::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcControllerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcController::setPredefinedType(boost::optional< ::Ifc4::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcControllerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcController::declaration() const { return *IFC4_IfcController_type; }
@@ -12794,7 +12794,7 @@ Ifc4::IfcConversionBasedUnitWithOffset::IfcConversionBasedUnitWithOffset(::Ifc4:
 
 // Function implementations for IfcCooledBeam
 boost::optional< ::Ifc4::IfcCooledBeamTypeEnum::Value > Ifc4::IfcCooledBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCooledBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCooledBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCooledBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCooledBeam::declaration() const { return *IFC4_IfcCooledBeam_type; }
@@ -12814,7 +12814,7 @@ Ifc4::IfcCooledBeamType::IfcCooledBeamType(std::string v1_GlobalId, ::Ifc4::IfcO
 
 // Function implementations for IfcCoolingTower
 boost::optional< ::Ifc4::IfcCoolingTowerTypeEnum::Value > Ifc4::IfcCoolingTower::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCoolingTowerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCoolingTowerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCoolingTowerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCoolingTower::declaration() const { return *IFC4_IfcCoolingTower_type; }
@@ -12848,11 +12848,11 @@ Ifc4::IfcCoordinateOperation::IfcCoordinateOperation(::Ifc4::IfcCoordinateRefere
 std::string Ifc4::IfcCoordinateReferenceSystem::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4::IfcCoordinateReferenceSystem::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcCoordinateReferenceSystem::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcCoordinateReferenceSystem::GeodeticDatum() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4::IfcCoordinateReferenceSystem::VerticalDatum() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 ::Ifc4::IfcCoordinateOperation::list::ptr Ifc4::IfcCoordinateReferenceSystem::HasCoordinateOperation() const { return data_->getInverse(IFC4_IfcCoordinateOperation_type, 0)->as<IfcCoordinateOperation>(); }
 
@@ -12863,11 +12863,11 @@ Ifc4::IfcCoordinateReferenceSystem::IfcCoordinateReferenceSystem(std::string v1_
 
 // Function implementations for IfcCostItem
 boost::optional< ::Ifc4::IfcCostItemTypeEnum::Value > Ifc4::IfcCostItem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4::IfcCostItemTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCostItemTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCostItemTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcCostValue >::ptr > Ifc4::IfcCostItem::CostValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4::IfcCostValue >(); }
-void Ifc4::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcPhysicalQuantity >::ptr > Ifc4::IfcCostItem::CostQuantities() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4::IfcPhysicalQuantity >(); }
-void Ifc4::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCostItem::declaration() const { return *IFC4_IfcCostItem_type; }
@@ -12877,13 +12877,13 @@ Ifc4::IfcCostItem::IfcCostItem(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory*
 
 // Function implementations for IfcCostSchedule
 boost::optional< ::Ifc4::IfcCostScheduleTypeEnum::Value > Ifc4::IfcCostSchedule::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4::IfcCostScheduleTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCostScheduleTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCostScheduleTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcCostSchedule::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcCostSchedule::SubmittedOn() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4::IfcCostSchedule::UpdateDate() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCostSchedule::declaration() const { return *IFC4_IfcCostSchedule_type; }
@@ -12901,7 +12901,7 @@ Ifc4::IfcCostValue::IfcCostValue(boost::optional< std::string > v1_Name, boost::
 
 // Function implementations for IfcCovering
 boost::optional< ::Ifc4::IfcCoveringTypeEnum::Value > Ifc4::IfcCovering::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCoveringTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCovering::setPredefinedType(boost::optional< ::Ifc4::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCoveringTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCovering::setPredefinedType(boost::optional< ::Ifc4::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCoveringTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4::IfcRelCoversSpaces::list::ptr Ifc4::IfcCovering::CoversSpaces() const { return data_->getInverse(IFC4_IfcRelCoversSpaces_type, 5)->as<IfcRelCoversSpaces>(); }
 ::Ifc4::IfcRelCoversBldgElements::list::ptr Ifc4::IfcCovering::CoversElements() const { return data_->getInverse(IFC4_IfcRelCoversBldgElements_type, 5)->as<IfcRelCoversBldgElements>(); }
@@ -12923,7 +12923,7 @@ Ifc4::IfcCoveringType::IfcCoveringType(std::string v1_GlobalId, ::Ifc4::IfcOwner
 
 // Function implementations for IfcCrewResource
 boost::optional< ::Ifc4::IfcCrewResourceTypeEnum::Value > Ifc4::IfcCrewResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcCrewResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCrewResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCrewResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCrewResource::declaration() const { return *IFC4_IfcCrewResource_type; }
@@ -12969,7 +12969,7 @@ void Ifc4::IfcCurrencyRelationship::setRelatedMonetaryUnit(::Ifc4::IfcMonetaryUn
 double Ifc4::IfcCurrencyRelationship::ExchangeRate() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4::IfcCurrencyRelationship::setExchangeRate(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcCurrencyRelationship::RateDateTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4::IfcLibraryInformation* Ifc4::IfcCurrencyRelationship::RateSource() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcLibraryInformation>(true); }
 void Ifc4::IfcCurrencyRelationship::setRateSource(::Ifc4::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -12981,7 +12981,7 @@ Ifc4::IfcCurrencyRelationship::IfcCurrencyRelationship(boost::optional< std::str
 
 // Function implementations for IfcCurtainWall
 boost::optional< ::Ifc4::IfcCurtainWallTypeEnum::Value > Ifc4::IfcCurtainWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcCurtainWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCurtainWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCurtainWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCurtainWall::declaration() const { return *IFC4_IfcCurtainWall_type; }
@@ -13043,7 +13043,7 @@ void Ifc4::IfcCurveStyle::setCurveWidth(::Ifc4::IfcSizeSelect* v) { {IfcWrite::I
 ::Ifc4::IfcColour* Ifc4::IfcCurveStyle::CurveColour() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcColour>(true); }
 void Ifc4::IfcCurveStyle::setCurveColour(::Ifc4::IfcColour* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4::IfcCurveStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcCurveStyle::declaration() const { return *IFC4_IfcCurveStyle_type; }
@@ -13053,7 +13053,7 @@ Ifc4::IfcCurveStyle::IfcCurveStyle(boost::optional< std::string > v1_Name, ::Ifc
 
 // Function implementations for IfcCurveStyleFont
 boost::optional< std::string > Ifc4::IfcCurveStyleFont::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc4::IfcCurveStyleFontPattern >::ptr Ifc4::IfcCurveStyleFont::PatternList() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4::IfcCurveStyleFontPattern >(); }
 void Ifc4::IfcCurveStyleFont::setPatternList(aggregate_of< ::Ifc4::IfcCurveStyleFontPattern >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -13065,7 +13065,7 @@ Ifc4::IfcCurveStyleFont::IfcCurveStyleFont(boost::optional< std::string > v1_Nam
 
 // Function implementations for IfcCurveStyleFontAndScaling
 boost::optional< std::string > Ifc4::IfcCurveStyleFontAndScaling::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4::IfcCurveStyleFontSelect* Ifc4::IfcCurveStyleFontAndScaling::CurveFont() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4::IfcCurveStyleFontSelect>(true); }
 void Ifc4::IfcCurveStyleFontAndScaling::setCurveFont(::Ifc4::IfcCurveStyleFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 double Ifc4::IfcCurveStyleFontAndScaling::CurveFontScaling() const {  double v = *data_->getArgument(2); return v; }
@@ -13101,7 +13101,7 @@ Ifc4::IfcCylindricalSurface::IfcCylindricalSurface(::Ifc4::IfcAxis2Placement3D*
 
 // Function implementations for IfcDamper
 boost::optional< ::Ifc4::IfcDamperTypeEnum::Value > Ifc4::IfcDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcDamper::setPredefinedType(boost::optional< ::Ifc4::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcDamper::setPredefinedType(boost::optional< ::Ifc4::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDamper::declaration() const { return *IFC4_IfcDamper_type; }
@@ -13125,7 +13125,7 @@ void Ifc4::IfcDerivedProfileDef::setParentProfile(::Ifc4::IfcProfileDef* v) { {I
 ::Ifc4::IfcCartesianTransformationOperator2D* Ifc4::IfcDerivedProfileDef::Operator() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4::IfcDerivedProfileDef::setOperator(::Ifc4::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcDerivedProfileDef::Label() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDerivedProfileDef::declaration() const { return *IFC4_IfcDerivedProfileDef_type; }
@@ -13139,7 +13139,7 @@ void Ifc4::IfcDerivedUnit::setElements(aggregate_of< ::Ifc4::IfcDerivedUnitEleme
 ::Ifc4::IfcDerivedUnitEnum::Value Ifc4::IfcDerivedUnit::UnitType() const {  return ::Ifc4::IfcDerivedUnitEnum::FromString(*data_->getArgument(1)); }
 void Ifc4::IfcDerivedUnit::setUnitType(::Ifc4::IfcDerivedUnitEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcDerivedUnitEnum::ToString(v)));data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcDerivedUnit::UserDefinedType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDerivedUnit::declaration() const { return *IFC4_IfcDerivedUnit_type; }
@@ -13193,7 +13193,7 @@ Ifc4::IfcDirection::IfcDirection(std::vector< double > /*[2:3]*/ v1_DirectionRat
 
 // Function implementations for IfcDiscreteAccessory
 boost::optional< ::Ifc4::IfcDiscreteAccessoryTypeEnum::Value > Ifc4::IfcDiscreteAccessory::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcDiscreteAccessoryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDiscreteAccessoryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDiscreteAccessoryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDiscreteAccessory::declaration() const { return *IFC4_IfcDiscreteAccessory_type; }
@@ -13213,7 +13213,7 @@ Ifc4::IfcDiscreteAccessoryType::IfcDiscreteAccessoryType(std::string v1_GlobalId
 
 // Function implementations for IfcDistributionChamberElement
 boost::optional< ::Ifc4::IfcDistributionChamberElementTypeEnum::Value > Ifc4::IfcDistributionChamberElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcDistributionChamberElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDistributionChamberElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDistributionChamberElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDistributionChamberElement::declaration() const { return *IFC4_IfcDistributionChamberElement_type; }
@@ -13292,11 +13292,11 @@ Ifc4::IfcDistributionFlowElementType::IfcDistributionFlowElementType(std::string
 
 // Function implementations for IfcDistributionPort
 boost::optional< ::Ifc4::IfcFlowDirectionEnum::Value > Ifc4::IfcDistributionPort::FlowDirection() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4::IfcFlowDirectionEnum::FromString(*data_->getArgument(7)); }
-void Ifc4::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFlowDirectionEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFlowDirectionEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4::IfcDistributionPortTypeEnum::Value > Ifc4::IfcDistributionPort::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcDistributionPortTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDistributionPortTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDistributionPortTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4::IfcDistributionSystemEnum::Value > Ifc4::IfcDistributionPort::SystemType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4::IfcDistributionSystemEnum::FromString(*data_->getArgument(9)); }
-void Ifc4::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDistributionPort::declaration() const { return *IFC4_IfcDistributionPort_type; }
@@ -13306,9 +13306,9 @@ Ifc4::IfcDistributionPort::IfcDistributionPort(std::string v1_GlobalId, ::Ifc4::
 
 // Function implementations for IfcDistributionSystem
 boost::optional< std::string > Ifc4::IfcDistributionSystem::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< ::Ifc4::IfcDistributionSystemEnum::Value > Ifc4::IfcDistributionSystem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4::IfcDistributionSystemEnum::FromString(*data_->getArgument(6)); }
-void Ifc4::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDistributionSystem::declaration() const { return *IFC4_IfcDistributionSystem_type; }
@@ -13322,35 +13322,35 @@ void Ifc4::IfcDocumentInformation::setIdentification(std::string v) { {IfcWrite:
 std::string Ifc4::IfcDocumentInformation::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4::IfcDocumentInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::Location() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::Purpose() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::IntendedUse() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::Scope() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::Revision() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4::IfcActorSelect* Ifc4::IfcDocumentInformation::DocumentOwner() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4::IfcActorSelect>(true); }
 void Ifc4::IfcDocumentInformation::setDocumentOwner(::Ifc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4::IfcDocumentInformation::Editors() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(9); return v; }
-void Ifc4::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::CreationTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::LastRevisionTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::ElectronicFormat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::ValidFrom() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformation::ValidUntil() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< ::Ifc4::IfcDocumentConfidentialityEnum::Value > Ifc4::IfcDocumentInformation::Confidentiality() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } return ::Ifc4::IfcDocumentConfidentialityEnum::FromString(*data_->getArgument(15)); }
-void Ifc4::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDocumentConfidentialityEnum::ToString(*v)));data_->setArgument(15,attr);} }
+void Ifc4::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDocumentConfidentialityEnum::ToString(*v)));}data_->setArgument(15,attr);} }
 boost::optional< ::Ifc4::IfcDocumentStatusEnum::Value > Ifc4::IfcDocumentInformation::Status() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } return ::Ifc4::IfcDocumentStatusEnum::FromString(*data_->getArgument(16)); }
-void Ifc4::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDocumentStatusEnum::ToString(*v)));data_->setArgument(16,attr);} }
+void Ifc4::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDocumentStatusEnum::ToString(*v)));}data_->setArgument(16,attr);} }
 
 ::Ifc4::IfcRelAssociatesDocument::list::ptr Ifc4::IfcDocumentInformation::DocumentInfoForObjects() const { return data_->getInverse(IFC4_IfcRelAssociatesDocument_type, 5)->as<IfcRelAssociatesDocument>(); }
 ::Ifc4::IfcDocumentReference::list::ptr Ifc4::IfcDocumentInformation::HasDocumentReferences() const { return data_->getInverse(IFC4_IfcDocumentReference_type, 4)->as<IfcDocumentReference>(); }
@@ -13368,7 +13368,7 @@ void Ifc4::IfcDocumentInformationRelationship::setRelatingDocument(::Ifc4::IfcDo
 aggregate_of< ::Ifc4::IfcDocumentInformation >::ptr Ifc4::IfcDocumentInformationRelationship::RelatedDocuments() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4::IfcDocumentInformation >(); }
 void Ifc4::IfcDocumentInformationRelationship::setRelatedDocuments(aggregate_of< ::Ifc4::IfcDocumentInformation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcDocumentInformationRelationship::RelationshipType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDocumentInformationRelationship::declaration() const { return *IFC4_IfcDocumentInformationRelationship_type; }
@@ -13378,7 +13378,7 @@ Ifc4::IfcDocumentInformationRelationship::IfcDocumentInformationRelationship(boo
 
 // Function implementations for IfcDocumentReference
 boost::optional< std::string > Ifc4::IfcDocumentReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4::IfcDocumentInformation* Ifc4::IfcDocumentReference::ReferencedDocument() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4::IfcDocumentInformation>(true); }
 void Ifc4::IfcDocumentReference::setReferencedDocument(::Ifc4::IfcDocumentInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -13391,15 +13391,15 @@ Ifc4::IfcDocumentReference::IfcDocumentReference(boost::optional< std::string >
 
 // Function implementations for IfcDoor
 boost::optional< double > Ifc4::IfcDoor::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4::IfcDoor::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4::IfcDoorTypeEnum::Value > Ifc4::IfcDoor::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcDoorTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcDoor::setPredefinedType(boost::optional< ::Ifc4::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDoorTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcDoor::setPredefinedType(boost::optional< ::Ifc4::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDoorTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4::IfcDoorTypeOperationEnum::Value > Ifc4::IfcDoor::OperationType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(11)); }
-void Ifc4::IfcDoor::setOperationType(boost::optional< ::Ifc4::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDoorTypeOperationEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4::IfcDoor::setOperationType(boost::optional< ::Ifc4::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDoorTypeOperationEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4::IfcDoor::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDoor::declaration() const { return *IFC4_IfcDoor_type; }
@@ -13409,31 +13409,31 @@ Ifc4::IfcDoor::IfcDoor(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Owne
 
 // Function implementations for IfcDoorLiningProperties
 boost::optional< double > Ifc4::IfcDoorLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::ThresholdDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::ThresholdThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::TransomThickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::TransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::LiningOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::ThresholdOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::CasingThickness() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::CasingDepth() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 ::Ifc4::IfcShapeAspect* Ifc4::IfcDoorLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(14)))->as<::Ifc4::IfcShapeAspect>(true); }
 void Ifc4::IfcDoorLiningProperties::setShapeAspectStyle(::Ifc4::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4::IfcDoorLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDoorLiningProperties::declaration() const { return *IFC4_IfcDoorLiningProperties_type; }
@@ -13443,11 +13443,11 @@ Ifc4::IfcDoorLiningProperties::IfcDoorLiningProperties(std::string v1_GlobalId,
 
 // Function implementations for IfcDoorPanelProperties
 boost::optional< double > Ifc4::IfcDoorPanelProperties::PanelDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4::IfcDoorPanelOperationEnum::Value Ifc4::IfcDoorPanelProperties::PanelOperation() const {  return ::Ifc4::IfcDoorPanelOperationEnum::FromString(*data_->getArgument(5)); }
 void Ifc4::IfcDoorPanelProperties::setPanelOperation(::Ifc4::IfcDoorPanelOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcDoorPanelOperationEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcDoorPanelProperties::PanelWidth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4::IfcDoorPanelPositionEnum::Value Ifc4::IfcDoorPanelProperties::PanelPosition() const {  return ::Ifc4::IfcDoorPanelPositionEnum::FromString(*data_->getArgument(7)); }
 void Ifc4::IfcDoorPanelProperties::setPanelPosition(::Ifc4::IfcDoorPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcDoorPanelPositionEnum::ToString(v)));data_->setArgument(7,attr);} }
 ::Ifc4::IfcShapeAspect* Ifc4::IfcDoorPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4::IfcShapeAspect>(true); }
@@ -13489,9 +13489,9 @@ void Ifc4::IfcDoorType::setPredefinedType(::Ifc4::IfcDoorTypeEnum::Value v) { {I
 ::Ifc4::IfcDoorTypeOperationEnum::Value Ifc4::IfcDoorType::OperationType() const {  return ::Ifc4::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(10)); }
 void Ifc4::IfcDoorType::setOperationType(::Ifc4::IfcDoorTypeOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcDoorTypeOperationEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4::IfcDoorType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4::IfcDoorType::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDoorType::declaration() const { return *IFC4_IfcDoorType_type; }
@@ -13517,7 +13517,7 @@ Ifc4::IfcDraughtingPreDefinedCurveFont::IfcDraughtingPreDefinedCurveFont(std::st
 
 // Function implementations for IfcDuctFitting
 boost::optional< ::Ifc4::IfcDuctFittingTypeEnum::Value > Ifc4::IfcDuctFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcDuctFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDuctFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDuctFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDuctFitting::declaration() const { return *IFC4_IfcDuctFitting_type; }
@@ -13537,7 +13537,7 @@ Ifc4::IfcDuctFittingType::IfcDuctFittingType(std::string v1_GlobalId, ::Ifc4::If
 
 // Function implementations for IfcDuctSegment
 boost::optional< ::Ifc4::IfcDuctSegmentTypeEnum::Value > Ifc4::IfcDuctSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcDuctSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDuctSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDuctSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDuctSegment::declaration() const { return *IFC4_IfcDuctSegment_type; }
@@ -13557,7 +13557,7 @@ Ifc4::IfcDuctSegmentType::IfcDuctSegmentType(std::string v1_GlobalId, ::Ifc4::If
 
 // Function implementations for IfcDuctSilencer
 boost::optional< ::Ifc4::IfcDuctSilencerTypeEnum::Value > Ifc4::IfcDuctSilencer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcDuctSilencerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDuctSilencerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDuctSilencerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcDuctSilencer::declaration() const { return *IFC4_IfcDuctSilencer_type; }
@@ -13611,7 +13611,7 @@ Ifc4::IfcEdgeLoop::IfcEdgeLoop(aggregate_of< ::Ifc4::IfcOrientedEdge >::ptr v1_E
 
 // Function implementations for IfcElectricAppliance
 boost::optional< ::Ifc4::IfcElectricApplianceTypeEnum::Value > Ifc4::IfcElectricAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcElectricApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcElectricAppliance::declaration() const { return *IFC4_IfcElectricAppliance_type; }
@@ -13631,7 +13631,7 @@ Ifc4::IfcElectricApplianceType::IfcElectricApplianceType(std::string v1_GlobalId
 
 // Function implementations for IfcElectricDistributionBoard
 boost::optional< ::Ifc4::IfcElectricDistributionBoardTypeEnum::Value > Ifc4::IfcElectricDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcElectricDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcElectricDistributionBoard::declaration() const { return *IFC4_IfcElectricDistributionBoard_type; }
@@ -13651,7 +13651,7 @@ Ifc4::IfcElectricDistributionBoardType::IfcElectricDistributionBoardType(std::st
 
 // Function implementations for IfcElectricFlowStorageDevice
 boost::optional< ::Ifc4::IfcElectricFlowStorageDeviceTypeEnum::Value > Ifc4::IfcElectricFlowStorageDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcElectricFlowStorageDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcElectricFlowStorageDevice::declaration() const { return *IFC4_IfcElectricFlowStorageDevice_type; }
@@ -13671,7 +13671,7 @@ Ifc4::IfcElectricFlowStorageDeviceType::IfcElectricFlowStorageDeviceType(std::st
 
 // Function implementations for IfcElectricGenerator
 boost::optional< ::Ifc4::IfcElectricGeneratorTypeEnum::Value > Ifc4::IfcElectricGenerator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcElectricGeneratorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricGeneratorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricGeneratorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcElectricGenerator::declaration() const { return *IFC4_IfcElectricGenerator_type; }
@@ -13691,7 +13691,7 @@ Ifc4::IfcElectricGeneratorType::IfcElectricGeneratorType(std::string v1_GlobalId
 
 // Function implementations for IfcElectricMotor
 boost::optional< ::Ifc4::IfcElectricMotorTypeEnum::Value > Ifc4::IfcElectricMotor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcElectricMotorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricMotorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricMotorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcElectricMotor::declaration() const { return *IFC4_IfcElectricMotor_type; }
@@ -13711,7 +13711,7 @@ Ifc4::IfcElectricMotorType::IfcElectricMotorType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcElectricTimeControl
 boost::optional< ::Ifc4::IfcElectricTimeControlTypeEnum::Value > Ifc4::IfcElectricTimeControl::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcElectricTimeControlTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricTimeControlTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElectricTimeControlTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcElectricTimeControl::declaration() const { return *IFC4_IfcElectricTimeControl_type; }
@@ -13731,7 +13731,7 @@ Ifc4::IfcElectricTimeControlType::IfcElectricTimeControlType(std::string v1_Glob
 
 // Function implementations for IfcElement
 boost::optional< std::string > Ifc4::IfcElement::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4::IfcRelFillsElement::list::ptr Ifc4::IfcElement::FillsVoids() const { return data_->getInverse(IFC4_IfcRelFillsElement_type, 5)->as<IfcRelFillsElement>(); }
 ::Ifc4::IfcRelConnectsElements::list::ptr Ifc4::IfcElement::ConnectedTo() const { return data_->getInverse(IFC4_IfcRelConnectsElements_type, 5)->as<IfcRelConnectsElements>(); }
@@ -13753,9 +13753,9 @@ Ifc4::IfcElement::IfcElement(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v
 
 // Function implementations for IfcElementAssembly
 boost::optional< ::Ifc4::IfcAssemblyPlaceEnum::Value > Ifc4::IfcElementAssembly::AssemblyPlace() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAssemblyPlaceEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcAssemblyPlaceEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4::IfcElementAssemblyTypeEnum::Value > Ifc4::IfcElementAssembly::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4::IfcElementAssemblyTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElementAssemblyTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElementAssemblyTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcElementAssembly::declaration() const { return *IFC4_IfcElementAssembly_type; }
@@ -13791,7 +13791,7 @@ Ifc4::IfcElementComponentType::IfcElementComponentType(std::string v1_GlobalId,
 
 // Function implementations for IfcElementQuantity
 boost::optional< std::string > Ifc4::IfcElementQuantity::MethodOfMeasurement() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4::IfcPhysicalQuantity >::ptr Ifc4::IfcElementQuantity::Quantities() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4::IfcPhysicalQuantity >(); }
 void Ifc4::IfcElementQuantity::setQuantities(aggregate_of< ::Ifc4::IfcPhysicalQuantity >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -13803,7 +13803,7 @@ Ifc4::IfcElementQuantity::IfcElementQuantity(std::string v1_GlobalId, ::Ifc4::If
 
 // Function implementations for IfcElementType
 boost::optional< std::string > Ifc4::IfcElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcElementType::declaration() const { return *IFC4_IfcElementType_type; }
@@ -13863,7 +13863,7 @@ Ifc4::IfcEnergyConversionDeviceType::IfcEnergyConversionDeviceType(std::string v
 
 // Function implementations for IfcEngine
 boost::optional< ::Ifc4::IfcEngineTypeEnum::Value > Ifc4::IfcEngine::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcEngineTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcEngine::setPredefinedType(boost::optional< ::Ifc4::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcEngineTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcEngine::setPredefinedType(boost::optional< ::Ifc4::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcEngineTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcEngine::declaration() const { return *IFC4_IfcEngine_type; }
@@ -13883,7 +13883,7 @@ Ifc4::IfcEngineType::IfcEngineType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHist
 
 // Function implementations for IfcEvaporativeCooler
 boost::optional< ::Ifc4::IfcEvaporativeCoolerTypeEnum::Value > Ifc4::IfcEvaporativeCooler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcEvaporativeCoolerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcEvaporativeCoolerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcEvaporativeCoolerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcEvaporativeCooler::declaration() const { return *IFC4_IfcEvaporativeCooler_type; }
@@ -13903,7 +13903,7 @@ Ifc4::IfcEvaporativeCoolerType::IfcEvaporativeCoolerType(std::string v1_GlobalId
 
 // Function implementations for IfcEvaporator
 boost::optional< ::Ifc4::IfcEvaporatorTypeEnum::Value > Ifc4::IfcEvaporator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcEvaporatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcEvaporatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcEvaporatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcEvaporator::declaration() const { return *IFC4_IfcEvaporator_type; }
@@ -13923,11 +13923,11 @@ Ifc4::IfcEvaporatorType::IfcEvaporatorType(std::string v1_GlobalId, ::Ifc4::IfcO
 
 // Function implementations for IfcEvent
 boost::optional< ::Ifc4::IfcEventTypeEnum::Value > Ifc4::IfcEvent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4::IfcEventTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4::IfcEvent::setPredefinedType(boost::optional< ::Ifc4::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcEventTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4::IfcEvent::setPredefinedType(boost::optional< ::Ifc4::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcEventTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4::IfcEventTriggerTypeEnum::Value > Ifc4::IfcEvent::EventTriggerType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcEventTriggerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcEventTriggerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4::IfcEvent::UserDefinedEventTriggerType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 ::Ifc4::IfcEventTime* Ifc4::IfcEvent::EventOccurenceTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4::IfcEventTime>(true); }
 void Ifc4::IfcEvent::setEventOccurenceTime(::Ifc4::IfcEventTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -13939,13 +13939,13 @@ Ifc4::IfcEvent::IfcEvent(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Ow
 
 // Function implementations for IfcEventTime
 boost::optional< std::string > Ifc4::IfcEventTime::ActualDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcEventTime::EarlyDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcEventTime::LateDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcEventTime::ScheduleDate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcEventTime::declaration() const { return *IFC4_IfcEventTime_type; }
@@ -13959,7 +13959,7 @@ void Ifc4::IfcEventType::setPredefinedType(::Ifc4::IfcEventTypeEnum::Value v) {
 ::Ifc4::IfcEventTriggerTypeEnum::Value Ifc4::IfcEventType::EventTriggerType() const {  return ::Ifc4::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(10)); }
 void Ifc4::IfcEventType::setEventTriggerType(::Ifc4::IfcEventTriggerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcEventTriggerTypeEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4::IfcEventType::UserDefinedEventTriggerType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcEventType::declaration() const { return *IFC4_IfcEventType_type; }
@@ -13969,9 +13969,9 @@ Ifc4::IfcEventType::IfcEventType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistor
 
 // Function implementations for IfcExtendedProperties
 boost::optional< std::string > Ifc4::IfcExtendedProperties::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcExtendedProperties::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4::IfcProperty >::ptr Ifc4::IfcExtendedProperties::Properties() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4::IfcProperty >(); }
 void Ifc4::IfcExtendedProperties::setProperties(aggregate_of< ::Ifc4::IfcProperty >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -13991,11 +13991,11 @@ Ifc4::IfcExternalInformation::IfcExternalInformation() : IfcUtil::IfcBaseEntity(
 
 // Function implementations for IfcExternalReference
 boost::optional< std::string > Ifc4::IfcExternalReference::Location() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcExternalReference::Identification() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcExternalReference::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4::IfcExternalReferenceRelationship::list::ptr Ifc4::IfcExternalReference::ExternalReferenceForResources() const { return data_->getInverse(IFC4_IfcExternalReferenceRelationship_type, 2)->as<IfcExternalReferenceRelationship>(); }
 
@@ -14018,7 +14018,7 @@ Ifc4::IfcExternalReferenceRelationship::IfcExternalReferenceRelationship(boost::
 
 // Function implementations for IfcExternalSpatialElement
 boost::optional< ::Ifc4::IfcExternalSpatialElementTypeEnum::Value > Ifc4::IfcExternalSpatialElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcExternalSpatialElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcExternalSpatialElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcExternalSpatialElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4::IfcRelSpaceBoundary::list::ptr Ifc4::IfcExternalSpatialElement::BoundedBy() const { return data_->getInverse(IFC4_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
 
@@ -14154,17 +14154,17 @@ Ifc4::IfcFacetedBrepWithVoids::IfcFacetedBrepWithVoids(::Ifc4::IfcClosedShell* v
 
 // Function implementations for IfcFailureConnectionCondition
 boost::optional< double > Ifc4::IfcFailureConnectionCondition::TensionFailureX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcFailureConnectionCondition::TensionFailureY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcFailureConnectionCondition::TensionFailureZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcFailureConnectionCondition::CompressionFailureX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4::IfcFailureConnectionCondition::CompressionFailureY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcFailureConnectionCondition::CompressionFailureZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFailureConnectionCondition::declaration() const { return *IFC4_IfcFailureConnectionCondition_type; }
@@ -14174,7 +14174,7 @@ Ifc4::IfcFailureConnectionCondition::IfcFailureConnectionCondition(boost::option
 
 // Function implementations for IfcFan
 boost::optional< ::Ifc4::IfcFanTypeEnum::Value > Ifc4::IfcFan::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcFanTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcFan::setPredefinedType(boost::optional< ::Ifc4::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFanTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcFan::setPredefinedType(boost::optional< ::Ifc4::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFanTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFan::declaration() const { return *IFC4_IfcFan_type; }
@@ -14194,7 +14194,7 @@ Ifc4::IfcFanType::IfcFanType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v
 
 // Function implementations for IfcFastener
 boost::optional< ::Ifc4::IfcFastenerTypeEnum::Value > Ifc4::IfcFastener::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcFastenerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcFastener::setPredefinedType(boost::optional< ::Ifc4::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFastenerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcFastener::setPredefinedType(boost::optional< ::Ifc4::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFastenerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFastener::declaration() const { return *IFC4_IfcFastener_type; }
@@ -14242,7 +14242,7 @@ Ifc4::IfcFeatureElementSubtraction::IfcFeatureElementSubtraction(std::string v1_
 aggregate_of_instance::ptr Ifc4::IfcFillAreaStyle::FillStyles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4::IfcFillAreaStyle::setFillStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4::IfcFillAreaStyle::ModelorDraughting() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4::IfcFillAreaStyle::setModelorDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcFillAreaStyle::setModelorDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFillAreaStyle::declaration() const { return *IFC4_IfcFillAreaStyle_type; }
@@ -14284,7 +14284,7 @@ Ifc4::IfcFillAreaStyleTiles::IfcFillAreaStyleTiles(aggregate_of< ::Ifc4::IfcVect
 
 // Function implementations for IfcFilter
 boost::optional< ::Ifc4::IfcFilterTypeEnum::Value > Ifc4::IfcFilter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcFilterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcFilter::setPredefinedType(boost::optional< ::Ifc4::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFilterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcFilter::setPredefinedType(boost::optional< ::Ifc4::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFilterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFilter::declaration() const { return *IFC4_IfcFilter_type; }
@@ -14304,7 +14304,7 @@ Ifc4::IfcFilterType::IfcFilterType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHist
 
 // Function implementations for IfcFireSuppressionTerminal
 boost::optional< ::Ifc4::IfcFireSuppressionTerminalTypeEnum::Value > Ifc4::IfcFireSuppressionTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcFireSuppressionTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFireSuppressionTerminal::declaration() const { return *IFC4_IfcFireSuppressionTerminal_type; }
@@ -14326,9 +14326,9 @@ Ifc4::IfcFireSuppressionTerminalType::IfcFireSuppressionTerminalType(std::string
 ::Ifc4::IfcCurve* Ifc4::IfcFixedReferenceSweptAreaSolid::Directrix() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4::IfcCurve>(true); }
 void Ifc4::IfcFixedReferenceSweptAreaSolid::setDirectrix(::Ifc4::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcFixedReferenceSweptAreaSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcFixedReferenceSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcFixedReferenceSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcFixedReferenceSweptAreaSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcFixedReferenceSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcFixedReferenceSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4::IfcDirection* Ifc4::IfcFixedReferenceSweptAreaSolid::FixedReference() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4::IfcDirection>(true); }
 void Ifc4::IfcFixedReferenceSweptAreaSolid::setFixedReference(::Ifc4::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -14372,7 +14372,7 @@ Ifc4::IfcFlowFittingType::IfcFlowFittingType(std::string v1_GlobalId, ::Ifc4::If
 
 // Function implementations for IfcFlowInstrument
 boost::optional< ::Ifc4::IfcFlowInstrumentTypeEnum::Value > Ifc4::IfcFlowInstrument::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcFlowInstrumentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFlowInstrumentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFlowInstrumentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFlowInstrument::declaration() const { return *IFC4_IfcFlowInstrument_type; }
@@ -14392,7 +14392,7 @@ Ifc4::IfcFlowInstrumentType::IfcFlowInstrumentType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcFlowMeter
 boost::optional< ::Ifc4::IfcFlowMeterTypeEnum::Value > Ifc4::IfcFlowMeter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcFlowMeterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFlowMeterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFlowMeterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFlowMeter::declaration() const { return *IFC4_IfcFlowMeter_type; }
@@ -14492,7 +14492,7 @@ Ifc4::IfcFlowTreatmentDeviceType::IfcFlowTreatmentDeviceType(std::string v1_Glob
 
 // Function implementations for IfcFooting
 boost::optional< ::Ifc4::IfcFootingTypeEnum::Value > Ifc4::IfcFooting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcFootingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcFooting::setPredefinedType(boost::optional< ::Ifc4::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFootingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcFooting::setPredefinedType(boost::optional< ::Ifc4::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFootingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFooting::declaration() const { return *IFC4_IfcFooting_type; }
@@ -14528,7 +14528,7 @@ Ifc4::IfcFurnishingElementType::IfcFurnishingElementType(std::string v1_GlobalId
 
 // Function implementations for IfcFurniture
 boost::optional< ::Ifc4::IfcFurnitureTypeEnum::Value > Ifc4::IfcFurniture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcFurnitureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFurniture::declaration() const { return *IFC4_IfcFurniture_type; }
@@ -14540,7 +14540,7 @@ Ifc4::IfcFurniture::IfcFurniture(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistor
 ::Ifc4::IfcAssemblyPlaceEnum::Value Ifc4::IfcFurnitureType::AssemblyPlace() const {  return ::Ifc4::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(9)); }
 void Ifc4::IfcFurnitureType::setAssemblyPlace(::Ifc4::IfcAssemblyPlaceEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcAssemblyPlaceEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4::IfcFurnitureTypeEnum::Value > Ifc4::IfcFurnitureType::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcFurnitureTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcFurnitureType::declaration() const { return *IFC4_IfcFurnitureType_type; }
@@ -14550,7 +14550,7 @@ Ifc4::IfcFurnitureType::IfcFurnitureType(std::string v1_GlobalId, ::Ifc4::IfcOwn
 
 // Function implementations for IfcGeographicElement
 boost::optional< ::Ifc4::IfcGeographicElementTypeEnum::Value > Ifc4::IfcGeographicElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcGeographicElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcGeographicElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcGeographicElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcGeographicElement::declaration() const { return *IFC4_IfcGeographicElement_type; }
@@ -14580,7 +14580,7 @@ Ifc4::IfcGeometricCurveSet::IfcGeometricCurveSet(aggregate_of_instance::ptr v1_E
 int Ifc4::IfcGeometricRepresentationContext::CoordinateSpaceDimension() const {  int v = *data_->getArgument(2); return v; }
 void Ifc4::IfcGeometricRepresentationContext::setCoordinateSpaceDimension(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcGeometricRepresentationContext::Precision() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4::IfcAxis2Placement* Ifc4::IfcGeometricRepresentationContext::WorldCoordinateSystem() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4::IfcAxis2Placement>(true); }
 void Ifc4::IfcGeometricRepresentationContext::setWorldCoordinateSystem(::Ifc4::IfcAxis2Placement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 ::Ifc4::IfcDirection* Ifc4::IfcGeometricRepresentationContext::TrueNorth() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4::IfcDirection>(true); }
@@ -14606,11 +14606,11 @@ Ifc4::IfcGeometricRepresentationItem::IfcGeometricRepresentationItem() : IfcRepr
 ::Ifc4::IfcGeometricRepresentationContext* Ifc4::IfcGeometricRepresentationSubContext::ParentContext() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcGeometricRepresentationContext>(true); }
 void Ifc4::IfcGeometricRepresentationSubContext::setParentContext(::Ifc4::IfcGeometricRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcGeometricRepresentationSubContext::TargetScale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4::IfcGeometricProjectionEnum::Value Ifc4::IfcGeometricRepresentationSubContext::TargetView() const {  return ::Ifc4::IfcGeometricProjectionEnum::FromString(*data_->getArgument(8)); }
 void Ifc4::IfcGeometricRepresentationSubContext::setTargetView(::Ifc4::IfcGeometricProjectionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcGeometricProjectionEnum::ToString(v)));data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4::IfcGeometricRepresentationSubContext::UserDefinedTargetView() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcGeometricRepresentationSubContext::declaration() const { return *IFC4_IfcGeometricRepresentationSubContext_type; }
@@ -14634,9 +14634,9 @@ void Ifc4::IfcGrid::setUAxes(aggregate_of< ::Ifc4::IfcGridAxis >::ptr v) { {IfcW
 aggregate_of< ::Ifc4::IfcGridAxis >::ptr Ifc4::IfcGrid::VAxes() const {  aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4::IfcGridAxis >(); }
 void Ifc4::IfcGrid::setVAxes(aggregate_of< ::Ifc4::IfcGridAxis >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcGridAxis >::ptr > Ifc4::IfcGrid::WAxes() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4::IfcGridAxis >(); }
-void Ifc4::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4::IfcGridTypeEnum::Value > Ifc4::IfcGrid::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcGridTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcGrid::setPredefinedType(boost::optional< ::Ifc4::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcGridTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcGrid::setPredefinedType(boost::optional< ::Ifc4::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcGridTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 ::Ifc4::IfcRelContainedInSpatialStructure::list::ptr Ifc4::IfcGrid::ContainedInStructure() const { return data_->getInverse(IFC4_IfcRelContainedInSpatialStructure_type, 4)->as<IfcRelContainedInSpatialStructure>(); }
 
@@ -14647,7 +14647,7 @@ Ifc4::IfcGrid::IfcGrid(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Owne
 
 // Function implementations for IfcGridAxis
 boost::optional< std::string > Ifc4::IfcGridAxis::AxisTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4::IfcCurve* Ifc4::IfcGridAxis::AxisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4::IfcCurve>(true); }
 void Ifc4::IfcGridAxis::setAxisCurve(::Ifc4::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 bool Ifc4::IfcGridAxis::SameSense() const {  bool v = *data_->getArgument(2); return v; }
@@ -14698,7 +14698,7 @@ Ifc4::IfcHalfSpaceSolid::IfcHalfSpaceSolid(::Ifc4::IfcSurface* v1_BaseSurface, b
 
 // Function implementations for IfcHeatExchanger
 boost::optional< ::Ifc4::IfcHeatExchangerTypeEnum::Value > Ifc4::IfcHeatExchanger::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcHeatExchangerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcHeatExchangerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcHeatExchangerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcHeatExchanger::declaration() const { return *IFC4_IfcHeatExchanger_type; }
@@ -14718,7 +14718,7 @@ Ifc4::IfcHeatExchangerType::IfcHeatExchangerType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcHumidifier
 boost::optional< ::Ifc4::IfcHumidifierTypeEnum::Value > Ifc4::IfcHumidifier::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcHumidifierTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcHumidifierTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcHumidifierTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcHumidifier::declaration() const { return *IFC4_IfcHumidifier_type; }
@@ -14746,11 +14746,11 @@ void Ifc4::IfcIShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWriteA
 double Ifc4::IfcIShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4::IfcIShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcIShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4::IfcIShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4::IfcIShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcIShapeProfileDef::declaration() const { return *IFC4_IfcIShapeProfileDef_type; }
@@ -14772,7 +14772,7 @@ Ifc4::IfcImageTexture::IfcImageTexture(bool v1_RepeatS, bool v2_RepeatT, boost::
 ::Ifc4::IfcTessellatedFaceSet* Ifc4::IfcIndexedColourMap::MappedTo() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4::IfcTessellatedFaceSet>(true); }
 void Ifc4::IfcIndexedColourMap::setMappedTo(::Ifc4::IfcTessellatedFaceSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4::IfcIndexedColourMap::Opacity() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4::IfcColourRgbList* Ifc4::IfcIndexedColourMap::Colours() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4::IfcColourRgbList>(true); }
 void Ifc4::IfcIndexedColourMap::setColours(::Ifc4::IfcColourRgbList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::vector< int > /*[1:?]*/ Ifc4::IfcIndexedColourMap::ColourIndex() const {  std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
@@ -14788,9 +14788,9 @@ Ifc4::IfcIndexedColourMap::IfcIndexedColourMap(::Ifc4::IfcTessellatedFaceSet* v1
 ::Ifc4::IfcCartesianPointList* Ifc4::IfcIndexedPolyCurve::Points() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4::IfcCartesianPointList>(true); }
 void Ifc4::IfcIndexedPolyCurve::setPoints(::Ifc4::IfcCartesianPointList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4::IfcIndexedPolyCurve::Segments() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
-void Ifc4::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4::IfcIndexedPolyCurve::SelfIntersect() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcIndexedPolyCurve::declaration() const { return *IFC4_IfcIndexedPolyCurve_type; }
@@ -14833,7 +14833,7 @@ Ifc4::IfcIndexedTextureMap::IfcIndexedTextureMap(aggregate_of< ::Ifc4::IfcSurfac
 
 // Function implementations for IfcIndexedTriangleTextureMap
 boost::optional< std::vector< std::vector< int > > > Ifc4::IfcIndexedTriangleTextureMap::TexCoordIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
-void Ifc4::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcIndexedTriangleTextureMap::declaration() const { return *IFC4_IfcIndexedTriangleTextureMap_type; }
@@ -14843,7 +14843,7 @@ Ifc4::IfcIndexedTriangleTextureMap::IfcIndexedTriangleTextureMap(aggregate_of< :
 
 // Function implementations for IfcInterceptor
 boost::optional< ::Ifc4::IfcInterceptorTypeEnum::Value > Ifc4::IfcInterceptor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcInterceptorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcInterceptorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcInterceptorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcInterceptor::declaration() const { return *IFC4_IfcInterceptor_type; }
@@ -14871,13 +14871,13 @@ Ifc4::IfcIntersectionCurve::IfcIntersectionCurve(::Ifc4::IfcCurve* v1_Curve3D, a
 
 // Function implementations for IfcInventory
 boost::optional< ::Ifc4::IfcInventoryTypeEnum::Value > Ifc4::IfcInventory::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4::IfcInventoryTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4::IfcInventory::setPredefinedType(boost::optional< ::Ifc4::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcInventoryTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4::IfcInventory::setPredefinedType(boost::optional< ::Ifc4::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcInventoryTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 ::Ifc4::IfcActorSelect* Ifc4::IfcInventory::Jurisdiction() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcActorSelect>(true); }
 void Ifc4::IfcInventory::setJurisdiction(::Ifc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcPerson >::ptr > Ifc4::IfcInventory::ResponsiblePersons() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4::IfcPerson >(); }
-void Ifc4::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcInventory::LastUpdateDate() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4::IfcCostValue* Ifc4::IfcInventory::CurrentValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4::IfcCostValue>(true); }
 void Ifc4::IfcInventory::setCurrentValue(::Ifc4::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4::IfcCostValue* Ifc4::IfcInventory::OriginalValue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4::IfcCostValue>(true); }
@@ -14913,7 +14913,7 @@ Ifc4::IfcIrregularTimeSeriesValue::IfcIrregularTimeSeriesValue(std::string v1_Ti
 
 // Function implementations for IfcJunctionBox
 boost::optional< ::Ifc4::IfcJunctionBoxTypeEnum::Value > Ifc4::IfcJunctionBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcJunctionBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcJunctionBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcJunctionBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcJunctionBox::declaration() const { return *IFC4_IfcJunctionBox_type; }
@@ -14935,15 +14935,15 @@ Ifc4::IfcJunctionBoxType::IfcJunctionBoxType(std::string v1_GlobalId, ::Ifc4::If
 double Ifc4::IfcLShapeProfileDef::Depth() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4::IfcLShapeProfileDef::setDepth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcLShapeProfileDef::Width() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 double Ifc4::IfcLShapeProfileDef::Thickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4::IfcLShapeProfileDef::setThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcLShapeProfileDef::FilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcLShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4::IfcLShapeProfileDef::LegSlope() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcLShapeProfileDef::declaration() const { return *IFC4_IfcLShapeProfileDef_type; }
@@ -14953,7 +14953,7 @@ Ifc4::IfcLShapeProfileDef::IfcLShapeProfileDef(::Ifc4::IfcProfileTypeEnum::Value
 
 // Function implementations for IfcLaborResource
 boost::optional< ::Ifc4::IfcLaborResourceTypeEnum::Value > Ifc4::IfcLaborResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcLaborResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcLaborResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcLaborResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcLaborResource::declaration() const { return *IFC4_IfcLaborResource_type; }
@@ -14985,7 +14985,7 @@ Ifc4::IfcLagTime::IfcLagTime(boost::optional< std::string > v1_Name, boost::opti
 
 // Function implementations for IfcLamp
 boost::optional< ::Ifc4::IfcLampTypeEnum::Value > Ifc4::IfcLamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcLampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcLamp::setPredefinedType(boost::optional< ::Ifc4::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcLampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcLamp::setPredefinedType(boost::optional< ::Ifc4::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcLampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcLamp::declaration() const { return *IFC4_IfcLamp_type; }
@@ -15007,15 +15007,15 @@ Ifc4::IfcLampType::IfcLampType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory*
 std::string Ifc4::IfcLibraryInformation::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4::IfcLibraryInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcLibraryInformation::Version() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4::IfcActorSelect* Ifc4::IfcLibraryInformation::Publisher() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4::IfcActorSelect>(true); }
 void Ifc4::IfcLibraryInformation::setPublisher(::Ifc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4::IfcLibraryInformation::VersionDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcLibraryInformation::Location() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcLibraryInformation::Description() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4::IfcRelAssociatesLibrary::list::ptr Ifc4::IfcLibraryInformation::LibraryInfoForObjects() const { return data_->getInverse(IFC4_IfcRelAssociatesLibrary_type, 5)->as<IfcRelAssociatesLibrary>(); }
 ::Ifc4::IfcLibraryReference::list::ptr Ifc4::IfcLibraryInformation::HasLibraryReferences() const { return data_->getInverse(IFC4_IfcLibraryReference_type, 5)->as<IfcLibraryReference>(); }
@@ -15027,9 +15027,9 @@ Ifc4::IfcLibraryInformation::IfcLibraryInformation(std::string v1_Name, boost::o
 
 // Function implementations for IfcLibraryReference
 boost::optional< std::string > Ifc4::IfcLibraryReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcLibraryReference::Language() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4::IfcLibraryInformation* Ifc4::IfcLibraryReference::ReferencedLibrary() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4::IfcLibraryInformation>(true); }
 void Ifc4::IfcLibraryReference::setReferencedLibrary(::Ifc4::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -15056,7 +15056,7 @@ Ifc4::IfcLightDistributionData::IfcLightDistributionData(double v1_MainPlaneAngl
 
 // Function implementations for IfcLightFixture
 boost::optional< ::Ifc4::IfcLightFixtureTypeEnum::Value > Ifc4::IfcLightFixture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcLightFixtureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcLightFixtureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcLightFixtureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcLightFixture::declaration() const { return *IFC4_IfcLightFixture_type; }
@@ -15088,13 +15088,13 @@ Ifc4::IfcLightIntensityDistribution::IfcLightIntensityDistribution(::Ifc4::IfcLi
 
 // Function implementations for IfcLightSource
 boost::optional< std::string > Ifc4::IfcLightSource::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4::IfcColourRgb* Ifc4::IfcLightSource::LightColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4::IfcColourRgb>(true); }
 void Ifc4::IfcLightSource::setLightColour(::Ifc4::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcLightSource::AmbientIntensity() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcLightSource::Intensity() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcLightSource::declaration() const { return *IFC4_IfcLightSource_type; }
@@ -15162,7 +15162,7 @@ Ifc4::IfcLightSourcePositional::IfcLightSourcePositional(boost::optional< std::s
 ::Ifc4::IfcDirection* Ifc4::IfcLightSourceSpot::Orientation() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4::IfcDirection>(true); }
 void Ifc4::IfcLightSourceSpot::setOrientation(::Ifc4::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcLightSourceSpot::ConcentrationExponent() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 double Ifc4::IfcLightSourceSpot::SpreadAngle() const {  double v = *data_->getArgument(11); return v; }
 void Ifc4::IfcLightSourceSpot::setSpreadAngle(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 double Ifc4::IfcLightSourceSpot::BeamWidthAngle() const {  double v = *data_->getArgument(12); return v; }
@@ -15224,11 +15224,11 @@ void Ifc4::IfcMapConversion::setNorthings(double v) { {IfcWrite::IfcWriteArgumen
 double Ifc4::IfcMapConversion::OrthogonalHeight() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4::IfcMapConversion::setOrthogonalHeight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4::IfcMapConversion::XAxisAbscissa() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcMapConversion::XAxisOrdinate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcMapConversion::Scale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMapConversion::declaration() const { return *IFC4_IfcMapConversion_type; }
@@ -15252,9 +15252,9 @@ Ifc4::IfcMappedItem::IfcMappedItem(::Ifc4::IfcRepresentationMap* v1_MappingSourc
 std::string Ifc4::IfcMaterial::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4::IfcMaterial::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterial::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterial::Category() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4::IfcMaterialDefinitionRepresentation::list::ptr Ifc4::IfcMaterial::HasRepresentation() const { return data_->getInverse(IFC4_IfcMaterialDefinitionRepresentation_type, 3)->as<IfcMaterialDefinitionRepresentation>(); }
 ::Ifc4::IfcMaterialRelationship::list::ptr Ifc4::IfcMaterial::IsRelatedWith() const { return data_->getInverse(IFC4_IfcMaterialRelationship_type, 3)->as<IfcMaterialRelationship>(); }
@@ -15279,15 +15279,15 @@ Ifc4::IfcMaterialClassificationRelationship::IfcMaterialClassificationRelationsh
 
 // Function implementations for IfcMaterialConstituent
 boost::optional< std::string > Ifc4::IfcMaterialConstituent::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialConstituent::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4::IfcMaterial* Ifc4::IfcMaterialConstituent::Material() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4::IfcMaterial>(true); }
 void Ifc4::IfcMaterialConstituent::setMaterial(::Ifc4::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcMaterialConstituent::Fraction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialConstituent::Category() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4::IfcMaterialConstituentSet::list::ptr Ifc4::IfcMaterialConstituent::ToMaterialConstituentSet() const { return data_->getInverse(IFC4_IfcMaterialConstituentSet_type, 2)->as<IfcMaterialConstituentSet>(); }
 
@@ -15298,11 +15298,11 @@ Ifc4::IfcMaterialConstituent::IfcMaterialConstituent(boost::optional< std::strin
 
 // Function implementations for IfcMaterialConstituentSet
 boost::optional< std::string > Ifc4::IfcMaterialConstituentSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialConstituentSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcMaterialConstituent >::ptr > Ifc4::IfcMaterialConstituentSet::MaterialConstituents() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4::IfcMaterialConstituent >(); }
-void Ifc4::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMaterialConstituentSet::declaration() const { return *IFC4_IfcMaterialConstituentSet_type; }
@@ -15337,15 +15337,15 @@ void Ifc4::IfcMaterialLayer::setMaterial(::Ifc4::IfcMaterial* v) { {IfcWrite::If
 double Ifc4::IfcMaterialLayer::LayerThickness() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4::IfcMaterialLayer::setLayerThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< boost::logic::tribool > Ifc4::IfcMaterialLayer::IsVentilated() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } boost::logic::tribool v = *data_->getArgument(2); return v; }
-void Ifc4::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialLayer::Name() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialLayer::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialLayer::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4::IfcMaterialLayer::Priority() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4::IfcMaterialLayerSet::list::ptr Ifc4::IfcMaterialLayer::ToMaterialLayerSet() const { return data_->getInverse(IFC4_IfcMaterialLayerSet_type, 0)->as<IfcMaterialLayerSet>(); }
 
@@ -15358,9 +15358,9 @@ Ifc4::IfcMaterialLayer::IfcMaterialLayer(::Ifc4::IfcMaterial* v1_Material, doubl
 aggregate_of< ::Ifc4::IfcMaterialLayer >::ptr Ifc4::IfcMaterialLayerSet::MaterialLayers() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4::IfcMaterialLayer >(); }
 void Ifc4::IfcMaterialLayerSet::setMaterialLayers(aggregate_of< ::Ifc4::IfcMaterialLayer >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialLayerSet::LayerSetName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialLayerSet::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMaterialLayerSet::declaration() const { return *IFC4_IfcMaterialLayerSet_type; }
@@ -15378,7 +15378,7 @@ void Ifc4::IfcMaterialLayerSetUsage::setDirectionSense(::Ifc4::IfcDirectionSense
 double Ifc4::IfcMaterialLayerSetUsage::OffsetFromReferenceLine() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4::IfcMaterialLayerSetUsage::setOffsetFromReferenceLine(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcMaterialLayerSetUsage::ReferenceExtent() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMaterialLayerSetUsage::declaration() const { return *IFC4_IfcMaterialLayerSetUsage_type; }
@@ -15410,17 +15410,17 @@ Ifc4::IfcMaterialList::IfcMaterialList(aggregate_of< ::Ifc4::IfcMaterial >::ptr
 
 // Function implementations for IfcMaterialProfile
 boost::optional< std::string > Ifc4::IfcMaterialProfile::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialProfile::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4::IfcMaterial* Ifc4::IfcMaterialProfile::Material() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4::IfcMaterial>(true); }
 void Ifc4::IfcMaterialProfile::setMaterial(::Ifc4::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4::IfcProfileDef* Ifc4::IfcMaterialProfile::Profile() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcProfileDef>(true); }
 void Ifc4::IfcMaterialProfile::setProfile(::Ifc4::IfcProfileDef* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4::IfcMaterialProfile::Priority() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialProfile::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4::IfcMaterialProfileSet::list::ptr Ifc4::IfcMaterialProfile::ToMaterialProfileSet() const { return data_->getInverse(IFC4_IfcMaterialProfileSet_type, 2)->as<IfcMaterialProfileSet>(); }
 
@@ -15431,9 +15431,9 @@ Ifc4::IfcMaterialProfile::IfcMaterialProfile(boost::optional< std::string > v1_N
 
 // Function implementations for IfcMaterialProfileSet
 boost::optional< std::string > Ifc4::IfcMaterialProfileSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialProfileSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4::IfcMaterialProfile >::ptr Ifc4::IfcMaterialProfileSet::MaterialProfiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4::IfcMaterialProfile >(); }
 void Ifc4::IfcMaterialProfileSet::setMaterialProfiles(aggregate_of< ::Ifc4::IfcMaterialProfile >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 ::Ifc4::IfcCompositeProfileDef* Ifc4::IfcMaterialProfileSet::CompositeProfile() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcCompositeProfileDef>(true); }
@@ -15449,9 +15449,9 @@ Ifc4::IfcMaterialProfileSet::IfcMaterialProfileSet(boost::optional< std::string
 ::Ifc4::IfcMaterialProfileSet* Ifc4::IfcMaterialProfileSetUsage::ForProfileSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4::IfcMaterialProfileSet>(true); }
 void Ifc4::IfcMaterialProfileSetUsage::setForProfileSet(::Ifc4::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< int > Ifc4::IfcMaterialProfileSetUsage::CardinalPoint() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } int v = *data_->getArgument(1); return v; }
-void Ifc4::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcMaterialProfileSetUsage::ReferenceExtent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMaterialProfileSetUsage::declaration() const { return *IFC4_IfcMaterialProfileSetUsage_type; }
@@ -15463,7 +15463,7 @@ Ifc4::IfcMaterialProfileSetUsage::IfcMaterialProfileSetUsage(::Ifc4::IfcMaterial
 ::Ifc4::IfcMaterialProfileSet* Ifc4::IfcMaterialProfileSetUsageTapering::ForProfileEndSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcMaterialProfileSet>(true); }
 void Ifc4::IfcMaterialProfileSetUsageTapering::setForProfileEndSet(::Ifc4::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4::IfcMaterialProfileSetUsageTapering::CardinalEndPoint() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMaterialProfileSetUsageTapering::declaration() const { return *IFC4_IfcMaterialProfileSetUsageTapering_type; }
@@ -15497,7 +15497,7 @@ void Ifc4::IfcMaterialRelationship::setRelatingMaterial(::Ifc4::IfcMaterial* v)
 aggregate_of< ::Ifc4::IfcMaterial >::ptr Ifc4::IfcMaterialRelationship::RelatedMaterials() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4::IfcMaterial >(); }
 void Ifc4::IfcMaterialRelationship::setRelatedMaterials(aggregate_of< ::Ifc4::IfcMaterial >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcMaterialRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMaterialRelationship::declaration() const { return *IFC4_IfcMaterialRelationship_type; }
@@ -15528,11 +15528,11 @@ Ifc4::IfcMeasureWithUnit::IfcMeasureWithUnit(::Ifc4::IfcValue* v1_ValueComponent
 
 // Function implementations for IfcMechanicalFastener
 boost::optional< double > Ifc4::IfcMechanicalFastener::NominalDiameter() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4::IfcMechanicalFastener::NominalLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4::IfcMechanicalFastenerTypeEnum::Value > Ifc4::IfcMechanicalFastener::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcMechanicalFastenerTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcMechanicalFastenerTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMechanicalFastener::declaration() const { return *IFC4_IfcMechanicalFastener_type; }
@@ -15544,9 +15544,9 @@ Ifc4::IfcMechanicalFastener::IfcMechanicalFastener(std::string v1_GlobalId, ::If
 ::Ifc4::IfcMechanicalFastenerTypeEnum::Value Ifc4::IfcMechanicalFastenerType::PredefinedType() const {  return ::Ifc4::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4::IfcMechanicalFastenerType::setPredefinedType(::Ifc4::IfcMechanicalFastenerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcMechanicalFastenerTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcMechanicalFastenerType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcMechanicalFastenerType::NominalLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMechanicalFastenerType::declaration() const { return *IFC4_IfcMechanicalFastenerType_type; }
@@ -15556,7 +15556,7 @@ Ifc4::IfcMechanicalFastenerType::IfcMechanicalFastenerType(std::string v1_Global
 
 // Function implementations for IfcMedicalDevice
 boost::optional< ::Ifc4::IfcMedicalDeviceTypeEnum::Value > Ifc4::IfcMedicalDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcMedicalDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcMedicalDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcMedicalDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMedicalDevice::declaration() const { return *IFC4_IfcMedicalDevice_type; }
@@ -15576,7 +15576,7 @@ Ifc4::IfcMedicalDeviceType::IfcMedicalDeviceType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcMember
 boost::optional< ::Ifc4::IfcMemberTypeEnum::Value > Ifc4::IfcMember::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcMemberTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcMember::setPredefinedType(boost::optional< ::Ifc4::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcMemberTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcMember::setPredefinedType(boost::optional< ::Ifc4::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcMemberTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMember::declaration() const { return *IFC4_IfcMember_type; }
@@ -15606,7 +15606,7 @@ Ifc4::IfcMemberType::IfcMemberType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHist
 ::Ifc4::IfcBenchmarkEnum::Value Ifc4::IfcMetric::Benchmark() const {  return ::Ifc4::IfcBenchmarkEnum::FromString(*data_->getArgument(7)); }
 void Ifc4::IfcMetric::setBenchmark(::Ifc4::IfcBenchmarkEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcBenchmarkEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcMetric::ValueSource() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4::IfcMetricValueSelect* Ifc4::IfcMetric::DataValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4::IfcMetricValueSelect>(true); }
 void Ifc4::IfcMetric::setDataValue(::Ifc4::IfcMetricValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4::IfcReference* Ifc4::IfcMetric::ReferencePath() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4::IfcReference>(true); }
@@ -15638,7 +15638,7 @@ Ifc4::IfcMonetaryUnit::IfcMonetaryUnit(std::string v1_Currency) : IfcUtil::IfcBa
 
 // Function implementations for IfcMotorConnection
 boost::optional< ::Ifc4::IfcMotorConnectionTypeEnum::Value > Ifc4::IfcMotorConnection::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcMotorConnectionTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcMotorConnectionTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcMotorConnectionTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcMotorConnection::declaration() const { return *IFC4_IfcMotorConnection_type; }
@@ -15670,7 +15670,7 @@ Ifc4::IfcNamedUnit::IfcNamedUnit(::Ifc4::IfcDimensionalExponents* v1_Dimensions,
 
 // Function implementations for IfcObject
 boost::optional< std::string > Ifc4::IfcObject::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4::IfcRelDefinesByObject::list::ptr Ifc4::IfcObject::IsDeclaredBy() const { return data_->getInverse(IFC4_IfcRelDefinesByObject_type, 4)->as<IfcRelDefinesByObject>(); }
 ::Ifc4::IfcRelDefinesByObject::list::ptr Ifc4::IfcObject::Declares() const { return data_->getInverse(IFC4_IfcRelDefinesByObject_type, 5)->as<IfcRelDefinesByObject>(); }
@@ -15709,13 +15709,13 @@ Ifc4::IfcObjectPlacement::IfcObjectPlacement() : IfcUtil::IfcBaseEntity() {data_
 
 // Function implementations for IfcObjective
 boost::optional< aggregate_of< ::Ifc4::IfcConstraint >::ptr > Ifc4::IfcObjective::BenchmarkValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4::IfcConstraint >(); }
-void Ifc4::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4::IfcLogicalOperatorEnum::Value > Ifc4::IfcObjective::LogicalAggregator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcLogicalOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcLogicalOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcLogicalOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 ::Ifc4::IfcObjectiveEnum::Value Ifc4::IfcObjective::ObjectiveQualifier() const {  return ::Ifc4::IfcObjectiveEnum::FromString(*data_->getArgument(9)); }
 void Ifc4::IfcObjective::setObjectiveQualifier(::Ifc4::IfcObjectiveEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcObjectiveEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4::IfcObjective::UserDefinedQualifier() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcObjective::declaration() const { return *IFC4_IfcObjective_type; }
@@ -15725,7 +15725,7 @@ Ifc4::IfcObjective::IfcObjective(std::string v1_Name, boost::optional< std::stri
 
 // Function implementations for IfcOccupant
 boost::optional< ::Ifc4::IfcOccupantTypeEnum::Value > Ifc4::IfcOccupant::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4::IfcOccupantTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcOccupantTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcOccupantTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcOccupant::declaration() const { return *IFC4_IfcOccupant_type; }
@@ -15773,7 +15773,7 @@ Ifc4::IfcOpenShell::IfcOpenShell(aggregate_of< ::Ifc4::IfcFace >::ptr v1_CfsFace
 
 // Function implementations for IfcOpeningElement
 boost::optional< ::Ifc4::IfcOpeningElementTypeEnum::Value > Ifc4::IfcOpeningElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcOpeningElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcOpeningElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcOpeningElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4::IfcRelFillsElement::list::ptr Ifc4::IfcOpeningElement::HasFillings() const { return data_->getInverse(IFC4_IfcRelFillsElement_type, 4)->as<IfcRelFillsElement>(); }
 
@@ -15792,15 +15792,15 @@ Ifc4::IfcOpeningStandardCase::IfcOpeningStandardCase(std::string v1_GlobalId, ::
 
 // Function implementations for IfcOrganization
 boost::optional< std::string > Ifc4::IfcOrganization::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 std::string Ifc4::IfcOrganization::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4::IfcOrganization::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcOrganization::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcActorRole >::ptr > Ifc4::IfcOrganization::Roles() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4::IfcActorRole >(); }
-void Ifc4::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(3,attr);} }
+void Ifc4::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(3,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcAddress >::ptr > Ifc4::IfcOrganization::Addresses() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4::IfcAddress >(); }
-void Ifc4::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(4,attr);} }
+void Ifc4::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(4,attr);} }
 
 ::Ifc4::IfcOrganizationRelationship::list::ptr Ifc4::IfcOrganization::IsRelatedBy() const { return data_->getInverse(IFC4_IfcOrganizationRelationship_type, 3)->as<IfcOrganizationRelationship>(); }
 ::Ifc4::IfcOrganizationRelationship::list::ptr Ifc4::IfcOrganization::Relates() const { return data_->getInverse(IFC4_IfcOrganizationRelationship_type, 2)->as<IfcOrganizationRelationship>(); }
@@ -15845,7 +15845,7 @@ Ifc4::IfcOuterBoundaryCurve::IfcOuterBoundaryCurve(aggregate_of< ::Ifc4::IfcComp
 
 // Function implementations for IfcOutlet
 boost::optional< ::Ifc4::IfcOutletTypeEnum::Value > Ifc4::IfcOutlet::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcOutletTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcOutletTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcOutletTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcOutlet::declaration() const { return *IFC4_IfcOutlet_type; }
@@ -15869,11 +15869,11 @@ void Ifc4::IfcOwnerHistory::setOwningUser(::Ifc4::IfcPersonAndOrganization* v) {
 ::Ifc4::IfcApplication* Ifc4::IfcOwnerHistory::OwningApplication() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4::IfcApplication>(true); }
 void Ifc4::IfcOwnerHistory::setOwningApplication(::Ifc4::IfcApplication* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4::IfcStateEnum::Value > Ifc4::IfcOwnerHistory::State() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4::IfcStateEnum::FromString(*data_->getArgument(2)); }
-void Ifc4::IfcOwnerHistory::setState(boost::optional< ::Ifc4::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcStateEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4::IfcOwnerHistory::setState(boost::optional< ::Ifc4::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcStateEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< ::Ifc4::IfcChangeActionEnum::Value > Ifc4::IfcOwnerHistory::ChangeAction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4::IfcChangeActionEnum::FromString(*data_->getArgument(3)); }
-void Ifc4::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcChangeActionEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcChangeActionEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4::IfcOwnerHistory::LastModifiedDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4::IfcPersonAndOrganization* Ifc4::IfcOwnerHistory::LastModifyingUser() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4::IfcPersonAndOrganization>(true); }
 void Ifc4::IfcOwnerHistory::setLastModifyingUser(::Ifc4::IfcPersonAndOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4::IfcApplication* Ifc4::IfcOwnerHistory::LastModifyingApplication() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcApplication>(true); }
@@ -15923,7 +15923,7 @@ Ifc4::IfcPcurve::IfcPcurve(::Ifc4::IfcSurface* v1_BasisSurface, ::Ifc4::IfcCurve
 std::string Ifc4::IfcPerformanceHistory::LifeCyclePhase() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4::IfcPerformanceHistory::setLifeCyclePhase(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4::IfcPerformanceHistoryTypeEnum::Value > Ifc4::IfcPerformanceHistory::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4::IfcPerformanceHistoryTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPerformanceHistoryTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPerformanceHistoryTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPerformanceHistory::declaration() const { return *IFC4_IfcPerformanceHistory_type; }
@@ -15937,9 +15937,9 @@ void Ifc4::IfcPermeableCoveringProperties::setOperationType(::Ifc4::IfcPermeable
 ::Ifc4::IfcWindowPanelPositionEnum::Value Ifc4::IfcPermeableCoveringProperties::PanelPosition() const {  return ::Ifc4::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4::IfcPermeableCoveringProperties::setPanelPosition(::Ifc4::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcPermeableCoveringProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcPermeableCoveringProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4::IfcShapeAspect* Ifc4::IfcPermeableCoveringProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4::IfcShapeAspect>(true); }
 void Ifc4::IfcPermeableCoveringProperties::setShapeAspectStyle(::Ifc4::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -15951,11 +15951,11 @@ Ifc4::IfcPermeableCoveringProperties::IfcPermeableCoveringProperties(std::string
 
 // Function implementations for IfcPermit
 boost::optional< ::Ifc4::IfcPermitTypeEnum::Value > Ifc4::IfcPermit::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4::IfcPermitTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4::IfcPermit::setPredefinedType(boost::optional< ::Ifc4::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPermitTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4::IfcPermit::setPredefinedType(boost::optional< ::Ifc4::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPermitTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcPermit::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcPermit::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPermit::declaration() const { return *IFC4_IfcPermit_type; }
@@ -15965,21 +15965,21 @@ Ifc4::IfcPermit::IfcPermit(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_
 
 // Function implementations for IfcPerson
 boost::optional< std::string > Ifc4::IfcPerson::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcPerson::FamilyName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcPerson::GivenName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4::IfcPerson::MiddleNames() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4::IfcPerson::PrefixTitles() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4::IfcPerson::SuffixTitles() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcActorRole >::ptr > Ifc4::IfcPerson::Roles() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4::IfcActorRole >(); }
-void Ifc4::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcAddress >::ptr > Ifc4::IfcPerson::Addresses() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4::IfcAddress >(); }
-void Ifc4::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 ::Ifc4::IfcPersonAndOrganization::list::ptr Ifc4::IfcPerson::EngagedIn() const { return data_->getInverse(IFC4_IfcPersonAndOrganization_type, 0)->as<IfcPersonAndOrganization>(); }
 
@@ -15994,7 +15994,7 @@ void Ifc4::IfcPersonAndOrganization::setThePerson(::Ifc4::IfcPerson* v) { {IfcWr
 ::Ifc4::IfcOrganization* Ifc4::IfcPersonAndOrganization::TheOrganization() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4::IfcOrganization>(true); }
 void Ifc4::IfcPersonAndOrganization::setTheOrganization(::Ifc4::IfcOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcActorRole >::ptr > Ifc4::IfcPersonAndOrganization::Roles() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4::IfcActorRole >(); }
-void Ifc4::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPersonAndOrganization::declaration() const { return *IFC4_IfcPersonAndOrganization_type; }
@@ -16008,9 +16008,9 @@ void Ifc4::IfcPhysicalComplexQuantity::setHasQuantities(aggregate_of< ::Ifc4::If
 std::string Ifc4::IfcPhysicalComplexQuantity::Discrimination() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4::IfcPhysicalComplexQuantity::setDiscrimination(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcPhysicalComplexQuantity::Quality() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcPhysicalComplexQuantity::Usage() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPhysicalComplexQuantity::declaration() const { return *IFC4_IfcPhysicalComplexQuantity_type; }
@@ -16022,7 +16022,7 @@ Ifc4::IfcPhysicalComplexQuantity::IfcPhysicalComplexQuantity(std::string v1_Name
 std::string Ifc4::IfcPhysicalQuantity::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4::IfcPhysicalQuantity::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcPhysicalQuantity::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4::IfcExternalReferenceRelationship::list::ptr Ifc4::IfcPhysicalQuantity::HasExternalReferences() const { return data_->getInverse(IFC4_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4::IfcPhysicalComplexQuantity::list::ptr Ifc4::IfcPhysicalQuantity::PartOfComplex() const { return data_->getInverse(IFC4_IfcPhysicalComplexQuantity_type, 2)->as<IfcPhysicalComplexQuantity>(); }
@@ -16044,9 +16044,9 @@ Ifc4::IfcPhysicalSimpleQuantity::IfcPhysicalSimpleQuantity(std::string v1_Name,
 
 // Function implementations for IfcPile
 boost::optional< ::Ifc4::IfcPileTypeEnum::Value > Ifc4::IfcPile::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcPileTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcPile::setPredefinedType(boost::optional< ::Ifc4::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPileTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcPile::setPredefinedType(boost::optional< ::Ifc4::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPileTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4::IfcPileConstructionEnum::Value > Ifc4::IfcPile::ConstructionType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4::IfcPileConstructionEnum::FromString(*data_->getArgument(9)); }
-void Ifc4::IfcPile::setConstructionType(boost::optional< ::Ifc4::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPileConstructionEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4::IfcPile::setConstructionType(boost::optional< ::Ifc4::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPileConstructionEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPile::declaration() const { return *IFC4_IfcPile_type; }
@@ -16066,7 +16066,7 @@ Ifc4::IfcPileType::IfcPileType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory*
 
 // Function implementations for IfcPipeFitting
 boost::optional< ::Ifc4::IfcPipeFittingTypeEnum::Value > Ifc4::IfcPipeFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcPipeFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPipeFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPipeFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPipeFitting::declaration() const { return *IFC4_IfcPipeFitting_type; }
@@ -16086,7 +16086,7 @@ Ifc4::IfcPipeFittingType::IfcPipeFittingType(std::string v1_GlobalId, ::Ifc4::If
 
 // Function implementations for IfcPipeSegment
 boost::optional< ::Ifc4::IfcPipeSegmentTypeEnum::Value > Ifc4::IfcPipeSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcPipeSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPipeSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPipeSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPipeSegment::declaration() const { return *IFC4_IfcPipeSegment_type; }
@@ -16162,7 +16162,7 @@ Ifc4::IfcPlane::IfcPlane(::Ifc4::IfcAxis2Placement3D* v1_Position) : IfcElementa
 
 // Function implementations for IfcPlate
 boost::optional< ::Ifc4::IfcPlateTypeEnum::Value > Ifc4::IfcPlate::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcPlateTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcPlate::setPredefinedType(boost::optional< ::Ifc4::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPlateTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcPlate::setPredefinedType(boost::optional< ::Ifc4::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPlateTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPlate::declaration() const { return *IFC4_IfcPlate_type; }
@@ -16246,11 +16246,11 @@ Ifc4::IfcPolygonalBoundedHalfSpace::IfcPolygonalBoundedHalfSpace(::Ifc4::IfcSurf
 
 // Function implementations for IfcPolygonalFaceSet
 boost::optional< bool > Ifc4::IfcPolygonalFaceSet::Closed() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4::IfcIndexedPolygonalFace >::ptr Ifc4::IfcPolygonalFaceSet::Faces() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4::IfcIndexedPolygonalFace >(); }
 void Ifc4::IfcPolygonalFaceSet::setFaces(aggregate_of< ::Ifc4::IfcIndexedPolygonalFace >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4::IfcPolygonalFaceSet::PnIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPolygonalFaceSet::declaration() const { return *IFC4_IfcPolygonalFaceSet_type; }
@@ -16281,19 +16281,19 @@ Ifc4::IfcPort::IfcPort(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Owne
 
 // Function implementations for IfcPostalAddress
 boost::optional< std::string > Ifc4::IfcPostalAddress::InternalLocation() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4::IfcPostalAddress::AddressLines() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcPostalAddress::PostalBox() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcPostalAddress::Town() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcPostalAddress::Region() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcPostalAddress::PostalCode() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4::IfcPostalAddress::Country() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPostalAddress::declaration() const { return *IFC4_IfcPostalAddress_type; }
@@ -16363,11 +16363,11 @@ Ifc4::IfcPresentationItem::IfcPresentationItem() : IfcUtil::IfcBaseEntity() {dat
 std::string Ifc4::IfcPresentationLayerAssignment::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4::IfcPresentationLayerAssignment::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcPresentationLayerAssignment::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of_instance::ptr Ifc4::IfcPresentationLayerAssignment::AssignedItems() const {  aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
 void Ifc4::IfcPresentationLayerAssignment::setAssignedItems(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4::IfcPresentationLayerAssignment::Identifier() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPresentationLayerAssignment::declaration() const { return *IFC4_IfcPresentationLayerAssignment_type; }
@@ -16393,7 +16393,7 @@ Ifc4::IfcPresentationLayerWithStyle::IfcPresentationLayerWithStyle(std::string v
 
 // Function implementations for IfcPresentationStyle
 boost::optional< std::string > Ifc4::IfcPresentationStyle::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPresentationStyle::declaration() const { return *IFC4_IfcPresentationStyle_type; }
@@ -16413,7 +16413,7 @@ Ifc4::IfcPresentationStyleAssignment::IfcPresentationStyleAssignment(aggregate_o
 
 // Function implementations for IfcProcedure
 boost::optional< ::Ifc4::IfcProcedureTypeEnum::Value > Ifc4::IfcProcedure::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4::IfcProcedureTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProcedureTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProcedureTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcProcedure::declaration() const { return *IFC4_IfcProcedure_type; }
@@ -16433,9 +16433,9 @@ Ifc4::IfcProcedureType::IfcProcedureType(std::string v1_GlobalId, ::Ifc4::IfcOwn
 
 // Function implementations for IfcProcess
 boost::optional< std::string > Ifc4::IfcProcess::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcProcess::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4::IfcRelSequence::list::ptr Ifc4::IfcProcess::IsPredecessorTo() const { return data_->getInverse(IFC4_IfcRelSequence_type, 4)->as<IfcRelSequence>(); }
 ::Ifc4::IfcRelSequence::list::ptr Ifc4::IfcProcess::IsSuccessorFrom() const { return data_->getInverse(IFC4_IfcRelSequence_type, 5)->as<IfcRelSequence>(); }
@@ -16471,9 +16471,9 @@ Ifc4::IfcProductDefinitionShape::IfcProductDefinitionShape(boost::optional< std:
 
 // Function implementations for IfcProductRepresentation
 boost::optional< std::string > Ifc4::IfcProductRepresentation::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcProductRepresentation::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4::IfcRepresentation >::ptr Ifc4::IfcProductRepresentation::Representations() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4::IfcRepresentation >(); }
 void Ifc4::IfcProductRepresentation::setRepresentations(aggregate_of< ::Ifc4::IfcRepresentation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -16487,7 +16487,7 @@ Ifc4::IfcProductRepresentation::IfcProductRepresentation(boost::optional< std::s
 ::Ifc4::IfcProfileTypeEnum::Value Ifc4::IfcProfileDef::ProfileType() const {  return ::Ifc4::IfcProfileTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4::IfcProfileDef::setProfileType(::Ifc4::IfcProfileTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcProfileTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcProfileDef::ProfileName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4::IfcExternalReferenceRelationship::list::ptr Ifc4::IfcProfileDef::HasExternalReference() const { return data_->getInverse(IFC4_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4::IfcProfileProperties::list::ptr Ifc4::IfcProfileDef::HasProperties() const { return data_->getInverse(IFC4_IfcProfileProperties_type, 3)->as<IfcProfileProperties>(); }
@@ -16525,11 +16525,11 @@ Ifc4::IfcProjectLibrary::IfcProjectLibrary(std::string v1_GlobalId, ::Ifc4::IfcO
 
 // Function implementations for IfcProjectOrder
 boost::optional< ::Ifc4::IfcProjectOrderTypeEnum::Value > Ifc4::IfcProjectOrder::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4::IfcProjectOrderTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProjectOrderTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProjectOrderTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcProjectOrder::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcProjectOrder::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcProjectOrder::declaration() const { return *IFC4_IfcProjectOrder_type; }
@@ -16539,9 +16539,9 @@ Ifc4::IfcProjectOrder::IfcProjectOrder(std::string v1_GlobalId, ::Ifc4::IfcOwner
 
 // Function implementations for IfcProjectedCRS
 boost::optional< std::string > Ifc4::IfcProjectedCRS::MapProjection() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcProjectedCRS::MapZone() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4::IfcNamedUnit* Ifc4::IfcProjectedCRS::MapUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcNamedUnit>(true); }
 void Ifc4::IfcProjectedCRS::setMapUnit(::Ifc4::IfcNamedUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -16553,7 +16553,7 @@ Ifc4::IfcProjectedCRS::IfcProjectedCRS(std::string v1_Name, boost::optional< std
 
 // Function implementations for IfcProjectionElement
 boost::optional< ::Ifc4::IfcProjectionElementTypeEnum::Value > Ifc4::IfcProjectionElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcProjectionElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProjectionElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProjectionElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcProjectionElement::declaration() const { return *IFC4_IfcProjectionElement_type; }
@@ -16565,7 +16565,7 @@ Ifc4::IfcProjectionElement::IfcProjectionElement(std::string v1_GlobalId, ::Ifc4
 std::string Ifc4::IfcProperty::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4::IfcProperty::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcProperty::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4::IfcPropertySet::list::ptr Ifc4::IfcProperty::PartOfPset() const { return data_->getInverse(IFC4_IfcPropertySet_type, 4)->as<IfcPropertySet>(); }
 ::Ifc4::IfcPropertyDependencyRelationship::list::ptr Ifc4::IfcProperty::PropertyForDependance() const { return data_->getInverse(IFC4_IfcPropertyDependencyRelationship_type, 2)->as<IfcPropertyDependencyRelationship>(); }
@@ -16620,7 +16620,7 @@ void Ifc4::IfcPropertyDependencyRelationship::setDependingProperty(::Ifc4::IfcPr
 ::Ifc4::IfcProperty* Ifc4::IfcPropertyDependencyRelationship::DependantProperty() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcProperty>(true); }
 void Ifc4::IfcPropertyDependencyRelationship::setDependantProperty(::Ifc4::IfcProperty* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcPropertyDependencyRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPropertyDependencyRelationship::declaration() const { return *IFC4_IfcPropertyDependencyRelationship_type; }
@@ -16630,7 +16630,7 @@ Ifc4::IfcPropertyDependencyRelationship::IfcPropertyDependencyRelationship(boost
 
 // Function implementations for IfcPropertyEnumeratedValue
 boost::optional< aggregate_of_instance::ptr > Ifc4::IfcPropertyEnumeratedValue::EnumerationValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4::IfcPropertyEnumeration* Ifc4::IfcPropertyEnumeratedValue::EnumerationReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcPropertyEnumeration>(true); }
 void Ifc4::IfcPropertyEnumeratedValue::setEnumerationReference(::Ifc4::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -16656,7 +16656,7 @@ Ifc4::IfcPropertyEnumeration::IfcPropertyEnumeration(std::string v1_Name, aggreg
 
 // Function implementations for IfcPropertyListValue
 boost::optional< aggregate_of_instance::ptr > Ifc4::IfcPropertyListValue::ListValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4::IfcUnit* Ifc4::IfcPropertyListValue::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcUnit>(true); }
 void Ifc4::IfcPropertyListValue::setUnit(::Ifc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -16668,7 +16668,7 @@ Ifc4::IfcPropertyListValue::IfcPropertyListValue(std::string v1_Name, boost::opt
 
 // Function implementations for IfcPropertyReferenceValue
 boost::optional< std::string > Ifc4::IfcPropertyReferenceValue::UsageName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4::IfcObjectReferenceSelect* Ifc4::IfcPropertyReferenceValue::PropertyReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcObjectReferenceSelect>(true); }
 void Ifc4::IfcPropertyReferenceValue::setPropertyReference(::Ifc4::IfcObjectReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -16701,9 +16701,9 @@ Ifc4::IfcPropertySetDefinition::IfcPropertySetDefinition(std::string v1_GlobalId
 
 // Function implementations for IfcPropertySetTemplate
 boost::optional< ::Ifc4::IfcPropertySetTemplateTypeEnum::Value > Ifc4::IfcPropertySetTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4::IfcPropertySetTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPropertySetTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPropertySetTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcPropertySetTemplate::ApplicableEntity() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 aggregate_of< ::Ifc4::IfcPropertyTemplate >::ptr Ifc4::IfcPropertySetTemplate::HasPropertyTemplates() const {  aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4::IfcPropertyTemplate >(); }
 void Ifc4::IfcPropertySetTemplate::setHasPropertyTemplates(aggregate_of< ::Ifc4::IfcPropertyTemplate >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(6,attr);} }
 
@@ -16728,17 +16728,17 @@ Ifc4::IfcPropertySingleValue::IfcPropertySingleValue(std::string v1_Name, boost:
 
 // Function implementations for IfcPropertyTableValue
 boost::optional< aggregate_of_instance::ptr > Ifc4::IfcPropertyTableValue::DefiningValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4::IfcPropertyTableValue::DefinedValues() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(3); return v; }
-void Ifc4::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcPropertyTableValue::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4::IfcUnit* Ifc4::IfcPropertyTableValue::DefiningUnit() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4::IfcUnit>(true); }
 void Ifc4::IfcPropertyTableValue::setDefiningUnit(::Ifc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4::IfcUnit* Ifc4::IfcPropertyTableValue::DefinedUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcUnit>(true); }
 void Ifc4::IfcPropertyTableValue::setDefinedUnit(::Ifc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4::IfcCurveInterpolationEnum::Value > Ifc4::IfcPropertyTableValue::CurveInterpolation() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4::IfcCurveInterpolationEnum::FromString(*data_->getArgument(7)); }
-void Ifc4::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCurveInterpolationEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcCurveInterpolationEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPropertyTableValue::declaration() const { return *IFC4_IfcPropertyTableValue_type; }
@@ -16766,7 +16766,7 @@ Ifc4::IfcPropertyTemplateDefinition::IfcPropertyTemplateDefinition(std::string v
 
 // Function implementations for IfcProtectiveDevice
 boost::optional< ::Ifc4::IfcProtectiveDeviceTypeEnum::Value > Ifc4::IfcProtectiveDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcProtectiveDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProtectiveDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProtectiveDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcProtectiveDevice::declaration() const { return *IFC4_IfcProtectiveDevice_type; }
@@ -16776,7 +16776,7 @@ Ifc4::IfcProtectiveDevice::IfcProtectiveDevice(std::string v1_GlobalId, ::Ifc4::
 
 // Function implementations for IfcProtectiveDeviceTrippingUnit
 boost::optional< ::Ifc4::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > Ifc4::IfcProtectiveDeviceTrippingUnit::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcProtectiveDeviceTrippingUnitTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcProtectiveDeviceTrippingUnit::declaration() const { return *IFC4_IfcProtectiveDeviceTrippingUnit_type; }
@@ -16808,7 +16808,7 @@ Ifc4::IfcProtectiveDeviceType::IfcProtectiveDeviceType(std::string v1_GlobalId,
 ::Ifc4::IfcObjectTypeEnum::Value Ifc4::IfcProxy::ProxyType() const {  return ::Ifc4::IfcObjectTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4::IfcProxy::setProxyType(::Ifc4::IfcObjectTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcObjectTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcProxy::Tag() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcProxy::declaration() const { return *IFC4_IfcProxy_type; }
@@ -16818,7 +16818,7 @@ Ifc4::IfcProxy::IfcProxy(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Ow
 
 // Function implementations for IfcPump
 boost::optional< ::Ifc4::IfcPumpTypeEnum::Value > Ifc4::IfcPump::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcPumpTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcPump::setPredefinedType(boost::optional< ::Ifc4::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPumpTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcPump::setPredefinedType(boost::optional< ::Ifc4::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcPumpTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcPump::declaration() const { return *IFC4_IfcPump_type; }
@@ -16840,7 +16840,7 @@ Ifc4::IfcPumpType::IfcPumpType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory*
 double Ifc4::IfcQuantityArea::AreaValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4::IfcQuantityArea::setAreaValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcQuantityArea::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcQuantityArea::declaration() const { return *IFC4_IfcQuantityArea_type; }
@@ -16852,7 +16852,7 @@ Ifc4::IfcQuantityArea::IfcQuantityArea(std::string v1_Name, boost::optional< std
 double Ifc4::IfcQuantityCount::CountValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4::IfcQuantityCount::setCountValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcQuantityCount::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcQuantityCount::declaration() const { return *IFC4_IfcQuantityCount_type; }
@@ -16864,7 +16864,7 @@ Ifc4::IfcQuantityCount::IfcQuantityCount(std::string v1_Name, boost::optional< s
 double Ifc4::IfcQuantityLength::LengthValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4::IfcQuantityLength::setLengthValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcQuantityLength::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcQuantityLength::declaration() const { return *IFC4_IfcQuantityLength_type; }
@@ -16884,7 +16884,7 @@ Ifc4::IfcQuantitySet::IfcQuantitySet(std::string v1_GlobalId, ::Ifc4::IfcOwnerHi
 double Ifc4::IfcQuantityTime::TimeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4::IfcQuantityTime::setTimeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcQuantityTime::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcQuantityTime::declaration() const { return *IFC4_IfcQuantityTime_type; }
@@ -16896,7 +16896,7 @@ Ifc4::IfcQuantityTime::IfcQuantityTime(std::string v1_Name, boost::optional< std
 double Ifc4::IfcQuantityVolume::VolumeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4::IfcQuantityVolume::setVolumeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcQuantityVolume::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcQuantityVolume::declaration() const { return *IFC4_IfcQuantityVolume_type; }
@@ -16908,7 +16908,7 @@ Ifc4::IfcQuantityVolume::IfcQuantityVolume(std::string v1_Name, boost::optional<
 double Ifc4::IfcQuantityWeight::WeightValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4::IfcQuantityWeight::setWeightValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcQuantityWeight::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcQuantityWeight::declaration() const { return *IFC4_IfcQuantityWeight_type; }
@@ -16918,7 +16918,7 @@ Ifc4::IfcQuantityWeight::IfcQuantityWeight(std::string v1_Name, boost::optional<
 
 // Function implementations for IfcRailing
 boost::optional< ::Ifc4::IfcRailingTypeEnum::Value > Ifc4::IfcRailing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcRailingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcRailing::setPredefinedType(boost::optional< ::Ifc4::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcRailingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcRailing::setPredefinedType(boost::optional< ::Ifc4::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcRailingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcRailing::declaration() const { return *IFC4_IfcRailing_type; }
@@ -16938,7 +16938,7 @@ Ifc4::IfcRailingType::IfcRailingType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHi
 
 // Function implementations for IfcRamp
 boost::optional< ::Ifc4::IfcRampTypeEnum::Value > Ifc4::IfcRamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcRampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcRamp::setPredefinedType(boost::optional< ::Ifc4::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcRampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcRamp::setPredefinedType(boost::optional< ::Ifc4::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcRampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcRamp::declaration() const { return *IFC4_IfcRamp_type; }
@@ -16948,7 +16948,7 @@ Ifc4::IfcRamp::IfcRamp(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Owne
 
 // Function implementations for IfcRampFlight
 boost::optional< ::Ifc4::IfcRampFlightTypeEnum::Value > Ifc4::IfcRampFlight::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcRampFlightTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcRampFlightTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcRampFlightTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcRampFlight::declaration() const { return *IFC4_IfcRampFlight_type; }
@@ -17000,9 +17000,9 @@ Ifc4::IfcRationalBSplineSurfaceWithKnots::IfcRationalBSplineSurfaceWithKnots(int
 double Ifc4::IfcRectangleHollowProfileDef::WallThickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4::IfcRectangleHollowProfileDef::setWallThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcRectangleHollowProfileDef::InnerFilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcRectangleHollowProfileDef::OuterFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcRectangleHollowProfileDef::declaration() const { return *IFC4_IfcRectangleHollowProfileDef_type; }
@@ -17062,19 +17062,19 @@ Ifc4::IfcRectangularTrimmedSurface::IfcRectangularTrimmedSurface(::Ifc4::IfcSurf
 ::Ifc4::IfcRecurrenceTypeEnum::Value Ifc4::IfcRecurrencePattern::RecurrenceType() const {  return ::Ifc4::IfcRecurrenceTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4::IfcRecurrencePattern::setRecurrenceType(::Ifc4::IfcRecurrenceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcRecurrenceTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4::IfcRecurrencePattern::DayComponent() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4::IfcRecurrencePattern::WeekdayComponent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4::IfcRecurrencePattern::MonthComponent() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4::IfcRecurrencePattern::Position() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< int > Ifc4::IfcRecurrencePattern::Interval() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } int v = *data_->getArgument(5); return v; }
-void Ifc4::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4::IfcRecurrencePattern::Occurrences() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcTimePeriod >::ptr > Ifc4::IfcRecurrencePattern::TimePeriods() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4::IfcTimePeriod >(); }
-void Ifc4::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcRecurrencePattern::declaration() const { return *IFC4_IfcRecurrencePattern_type; }
@@ -17084,13 +17084,13 @@ Ifc4::IfcRecurrencePattern::IfcRecurrencePattern(::Ifc4::IfcRecurrenceTypeEnum::
 
 // Function implementations for IfcReference
 boost::optional< std::string > Ifc4::IfcReference::TypeIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcReference::AttributeIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcReference::InstanceName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4::IfcReference::ListPositions() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4::IfcReference* Ifc4::IfcReference::InnerReference() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4::IfcReference>(true); }
 void Ifc4::IfcReference::setInnerReference(::Ifc4::IfcReference* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -17118,13 +17118,13 @@ void Ifc4::IfcReinforcementBarProperties::setTotalCrossSectionArea(double v) { {
 std::string Ifc4::IfcReinforcementBarProperties::SteelGrade() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4::IfcReinforcementBarProperties::setSteelGrade(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4::IfcReinforcingBarSurfaceEnum::Value > Ifc4::IfcReinforcementBarProperties::BarSurface() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(2)); }
-void Ifc4::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcReinforcementBarProperties::EffectiveDepth() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcReinforcementBarProperties::NominalBarDiameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4::IfcReinforcementBarProperties::BarCount() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcReinforcementBarProperties::declaration() const { return *IFC4_IfcReinforcementBarProperties_type; }
@@ -17134,7 +17134,7 @@ Ifc4::IfcReinforcementBarProperties::IfcReinforcementBarProperties(double v1_Tot
 
 // Function implementations for IfcReinforcementDefinitionProperties
 boost::optional< std::string > Ifc4::IfcReinforcementDefinitionProperties::DefinitionType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4::IfcSectionReinforcementProperties >::ptr Ifc4::IfcReinforcementDefinitionProperties::ReinforcementSectionDefinitions() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4::IfcSectionReinforcementProperties >(); }
 void Ifc4::IfcReinforcementDefinitionProperties::setReinforcementSectionDefinitions(aggregate_of< ::Ifc4::IfcSectionReinforcementProperties >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -17146,15 +17146,15 @@ Ifc4::IfcReinforcementDefinitionProperties::IfcReinforcementDefinitionProperties
 
 // Function implementations for IfcReinforcingBar
 boost::optional< double > Ifc4::IfcReinforcingBar::NominalDiameter() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingBar::CrossSectionArea() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingBar::BarLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4::IfcReinforcingBarTypeEnum::Value > Ifc4::IfcReinforcingBar::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcReinforcingBarTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcReinforcingBarTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4::IfcReinforcingBarSurfaceEnum::Value > Ifc4::IfcReinforcingBar::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcReinforcingBar::declaration() const { return *IFC4_IfcReinforcingBar_type; }
@@ -17166,17 +17166,17 @@ Ifc4::IfcReinforcingBar::IfcReinforcingBar(std::string v1_GlobalId, ::Ifc4::IfcO
 ::Ifc4::IfcReinforcingBarTypeEnum::Value Ifc4::IfcReinforcingBarType::PredefinedType() const {  return ::Ifc4::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4::IfcReinforcingBarType::setPredefinedType(::Ifc4::IfcReinforcingBarTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcReinforcingBarTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingBarType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingBarType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingBarType::BarLength() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4::IfcReinforcingBarSurfaceEnum::Value > Ifc4::IfcReinforcingBarType::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4::IfcReinforcingBarType::BendingShapeCode() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4::IfcReinforcingBarType::BendingParameters() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(15); return v; }
-void Ifc4::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcReinforcingBarType::declaration() const { return *IFC4_IfcReinforcingBarType_type; }
@@ -17186,7 +17186,7 @@ Ifc4::IfcReinforcingBarType::IfcReinforcingBarType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcReinforcingElement
 boost::optional< std::string > Ifc4::IfcReinforcingElement::SteelGrade() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcReinforcingElement::declaration() const { return *IFC4_IfcReinforcingElement_type; }
@@ -17204,23 +17204,23 @@ Ifc4::IfcReinforcingElementType::IfcReinforcingElementType(std::string v1_Global
 
 // Function implementations for IfcReinforcingMesh
 boost::optional< double > Ifc4::IfcReinforcingMesh::MeshLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMesh::MeshWidth() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMesh::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMesh::TransverseBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMesh::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMesh::TransverseBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMesh::LongitudinalBarSpacing() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMesh::TransverseBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< ::Ifc4::IfcReinforcingMeshTypeEnum::Value > Ifc4::IfcReinforcingMesh::PredefinedType() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } return ::Ifc4::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(17)); }
-void Ifc4::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcReinforcingMeshTypeEnum::ToString(*v)));data_->setArgument(17,attr);} }
+void Ifc4::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcReinforcingMeshTypeEnum::ToString(*v)));}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcReinforcingMesh::declaration() const { return *IFC4_IfcReinforcingMesh_type; }
@@ -17232,25 +17232,25 @@ Ifc4::IfcReinforcingMesh::IfcReinforcingMesh(std::string v1_GlobalId, ::Ifc4::If
 ::Ifc4::IfcReinforcingMeshTypeEnum::Value Ifc4::IfcReinforcingMeshType::PredefinedType() const {  return ::Ifc4::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4::IfcReinforcingMeshType::setPredefinedType(::Ifc4::IfcReinforcingMeshTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcReinforcingMeshTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMeshType::MeshLength() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMeshType::MeshWidth() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMeshType::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMeshType::TransverseBarNominalDiameter() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMeshType::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMeshType::TransverseBarCrossSectionArea() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMeshType::LongitudinalBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4::IfcReinforcingMeshType::TransverseBarSpacing() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4::IfcReinforcingMeshType::BendingShapeCode() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4::IfcReinforcingMeshType::BendingParameters() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(19); return v; }
-void Ifc4::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcReinforcingMeshType::declaration() const { return *IFC4_IfcReinforcingMeshType_type; }
@@ -17274,7 +17274,7 @@ Ifc4::IfcRelAggregates::IfcRelAggregates(std::string v1_GlobalId, ::Ifc4::IfcOwn
 aggregate_of< ::Ifc4::IfcObjectDefinition >::ptr Ifc4::IfcRelAssigns::RelatedObjects() const {  aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4::IfcObjectDefinition >(); }
 void Ifc4::IfcRelAssigns::setRelatedObjects(aggregate_of< ::Ifc4::IfcObjectDefinition >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4::IfcObjectTypeEnum::Value > Ifc4::IfcRelAssigns::RelatedObjectsType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4::IfcObjectTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcObjectTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcObjectTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcRelAssigns::declaration() const { return *IFC4_IfcRelAssigns_type; }
@@ -17388,7 +17388,7 @@ Ifc4::IfcRelAssociatesClassification::IfcRelAssociatesClassification(std::string
 
 // Function implementations for IfcRelAssociatesConstraint
 boost::optional< std::string > Ifc4::IfcRelAssociatesConstraint::Intent() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4::IfcConstraint* Ifc4::IfcRelAssociatesConstraint::RelatingConstraint() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcConstraint>(true); }
 void Ifc4::IfcRelAssociatesConstraint::setRelatingConstraint(::Ifc4::IfcConstraint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -17514,7 +17514,7 @@ void Ifc4::IfcRelConnectsStructuralMember::setAppliedCondition(::Ifc4::IfcBounda
 ::Ifc4::IfcStructuralConnectionCondition* Ifc4::IfcRelConnectsStructuralMember::AdditionalConditions() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4::IfcStructuralConnectionCondition>(true); }
 void Ifc4::IfcRelConnectsStructuralMember::setAdditionalConditions(::Ifc4::IfcStructuralConnectionCondition* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4::IfcRelConnectsStructuralMember::SupportedLength() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4::IfcAxis2Placement3D* Ifc4::IfcRelConnectsStructuralMember::ConditionCoordinateSystem() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4::IfcAxis2Placement3D>(true); }
 void Ifc4::IfcRelConnectsStructuralMember::setConditionCoordinateSystem(::Ifc4::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -17538,7 +17538,7 @@ Ifc4::IfcRelConnectsWithEccentricity::IfcRelConnectsWithEccentricity(std::string
 aggregate_of< ::Ifc4::IfcElement >::ptr Ifc4::IfcRelConnectsWithRealizingElements::RealizingElements() const {  aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4::IfcElement >(); }
 void Ifc4::IfcRelConnectsWithRealizingElements::setRealizingElements(aggregate_of< ::Ifc4::IfcElement >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcRelConnectsWithRealizingElements::ConnectionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcRelConnectsWithRealizingElements::declaration() const { return *IFC4_IfcRelConnectsWithRealizingElements_type; }
@@ -17690,7 +17690,7 @@ void Ifc4::IfcRelInterferesElements::setRelatedElement(::Ifc4::IfcElement* v) {
 ::Ifc4::IfcConnectionGeometry* Ifc4::IfcRelInterferesElements::InterferenceGeometry() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcConnectionGeometry>(true); }
 void Ifc4::IfcRelInterferesElements::setInterferenceGeometry(::Ifc4::IfcConnectionGeometry* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcRelInterferesElements::InterferenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::logic::tribool Ifc4::IfcRelInterferesElements::ImpliedOrder() const {  boost::logic::tribool v = *data_->getArgument(8); return v; }
 void Ifc4::IfcRelInterferesElements::setImpliedOrder(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -17744,9 +17744,9 @@ void Ifc4::IfcRelSequence::setRelatedProcess(::Ifc4::IfcProcess* v) { {IfcWrite:
 ::Ifc4::IfcLagTime* Ifc4::IfcRelSequence::TimeLag() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcLagTime>(true); }
 void Ifc4::IfcRelSequence::setTimeLag(::Ifc4::IfcLagTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4::IfcSequenceEnum::Value > Ifc4::IfcRelSequence::SequenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4::IfcSequenceEnum::FromString(*data_->getArgument(7)); }
-void Ifc4::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSequenceEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSequenceEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcRelSequence::UserDefinedSequenceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcRelSequence::declaration() const { return *IFC4_IfcRelSequence_type; }
@@ -17840,9 +17840,9 @@ Ifc4::IfcReparametrisedCompositeCurveSegment::IfcReparametrisedCompositeCurveSeg
 ::Ifc4::IfcRepresentationContext* Ifc4::IfcRepresentation::ContextOfItems() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4::IfcRepresentationContext>(true); }
 void Ifc4::IfcRepresentation::setContextOfItems(::Ifc4::IfcRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcRepresentation::RepresentationIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcRepresentation::RepresentationType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc4::IfcRepresentationItem >::ptr Ifc4::IfcRepresentation::Items() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4::IfcRepresentationItem >(); }
 void Ifc4::IfcRepresentation::setItems(aggregate_of< ::Ifc4::IfcRepresentationItem >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 
@@ -17857,9 +17857,9 @@ Ifc4::IfcRepresentation::IfcRepresentation(::Ifc4::IfcRepresentationContext* v1_
 
 // Function implementations for IfcRepresentationContext
 boost::optional< std::string > Ifc4::IfcRepresentationContext::ContextIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcRepresentationContext::ContextType() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4::IfcRepresentation::list::ptr Ifc4::IfcRepresentationContext::RepresentationsInContext() const { return data_->getInverse(IFC4_IfcRepresentation_type, 0)->as<IfcRepresentation>(); }
 
@@ -17894,9 +17894,9 @@ Ifc4::IfcRepresentationMap::IfcRepresentationMap(::Ifc4::IfcAxis2Placement* v1_M
 
 // Function implementations for IfcResource
 boost::optional< std::string > Ifc4::IfcResource::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcResource::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4::IfcRelAssignsToResource::list::ptr Ifc4::IfcResource::ResourceOf() const { return data_->getInverse(IFC4_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -17931,9 +17931,9 @@ Ifc4::IfcResourceConstraintRelationship::IfcResourceConstraintRelationship(boost
 
 // Function implementations for IfcResourceLevelRelationship
 boost::optional< std::string > Ifc4::IfcResourceLevelRelationship::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcResourceLevelRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcResourceLevelRelationship::declaration() const { return *IFC4_IfcResourceLevelRelationship_type; }
@@ -17943,35 +17943,35 @@ Ifc4::IfcResourceLevelRelationship::IfcResourceLevelRelationship(boost::optional
 
 // Function implementations for IfcResourceTime
 boost::optional< std::string > Ifc4::IfcResourceTime::ScheduleWork() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcResourceTime::ScheduleUsage() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcResourceTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcResourceTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcResourceTime::ScheduleContour() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcResourceTime::LevelingDelay() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< bool > Ifc4::IfcResourceTime::IsOverAllocated() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4::IfcResourceTime::StatusTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4::IfcResourceTime::ActualWork() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4::IfcResourceTime::ActualUsage() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4::IfcResourceTime::ActualStart() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4::IfcResourceTime::ActualFinish() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4::IfcResourceTime::RemainingWork() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4::IfcResourceTime::RemainingUsage() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4::IfcResourceTime::Completion() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcResourceTime::declaration() const { return *IFC4_IfcResourceTime_type; }
@@ -18027,7 +18027,7 @@ Ifc4::IfcRightCircularCylinder::IfcRightCircularCylinder(::Ifc4::IfcAxis2Placeme
 
 // Function implementations for IfcRoof
 boost::optional< ::Ifc4::IfcRoofTypeEnum::Value > Ifc4::IfcRoof::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcRoofTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcRoof::setPredefinedType(boost::optional< ::Ifc4::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcRoofTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcRoof::setPredefinedType(boost::optional< ::Ifc4::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcRoofTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcRoof::declaration() const { return *IFC4_IfcRoof_type; }
@@ -18051,9 +18051,9 @@ void Ifc4::IfcRoot::setGlobalId(std::string v) { {IfcWrite::IfcWriteArgument* at
 ::Ifc4::IfcOwnerHistory* Ifc4::IfcRoot::OwnerHistory() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4::IfcOwnerHistory>(true); }
 void Ifc4::IfcRoot::setOwnerHistory(::Ifc4::IfcOwnerHistory* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcRoot::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4::IfcRoot::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcRoot::declaration() const { return *IFC4_IfcRoot_type; }
@@ -18073,7 +18073,7 @@ Ifc4::IfcRoundedRectangleProfileDef::IfcRoundedRectangleProfileDef(::Ifc4::IfcPr
 
 // Function implementations for IfcSIUnit
 boost::optional< ::Ifc4::IfcSIPrefix::Value > Ifc4::IfcSIUnit::Prefix() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4::IfcSIPrefix::FromString(*data_->getArgument(2)); }
-void Ifc4::IfcSIUnit::setPrefix(boost::optional< ::Ifc4::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSIPrefix::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4::IfcSIUnit::setPrefix(boost::optional< ::Ifc4::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSIPrefix::ToString(*v)));}data_->setArgument(2,attr);} }
 ::Ifc4::IfcSIUnitName::Value Ifc4::IfcSIUnit::Name() const {  return ::Ifc4::IfcSIUnitName::FromString(*data_->getArgument(3)); }
 void Ifc4::IfcSIUnit::setName(::Ifc4::IfcSIUnitName::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcSIUnitName::ToString(v)));data_->setArgument(3,attr);} }
 
@@ -18085,7 +18085,7 @@ Ifc4::IfcSIUnit::IfcSIUnit(::Ifc4::IfcUnitEnum::Value v2_UnitType, boost::option
 
 // Function implementations for IfcSanitaryTerminal
 boost::optional< ::Ifc4::IfcSanitaryTerminalTypeEnum::Value > Ifc4::IfcSanitaryTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcSanitaryTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSanitaryTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSanitaryTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSanitaryTerminal::declaration() const { return *IFC4_IfcSanitaryTerminal_type; }
@@ -18105,11 +18105,11 @@ Ifc4::IfcSanitaryTerminalType::IfcSanitaryTerminalType(std::string v1_GlobalId,
 
 // Function implementations for IfcSchedulingTime
 boost::optional< std::string > Ifc4::IfcSchedulingTime::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< ::Ifc4::IfcDataOriginEnum::Value > Ifc4::IfcSchedulingTime::DataOrigin() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } return ::Ifc4::IfcDataOriginEnum::FromString(*data_->getArgument(1)); }
-void Ifc4::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDataOriginEnum::ToString(*v)));data_->setArgument(1,attr);} }
+void Ifc4::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcDataOriginEnum::ToString(*v)));}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcSchedulingTime::UserDefinedDataOrigin() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSchedulingTime::declaration() const { return *IFC4_IfcSchedulingTime_type; }
@@ -18145,7 +18145,7 @@ void Ifc4::IfcSectionReinforcementProperties::setLongitudinalStartPosition(doubl
 double Ifc4::IfcSectionReinforcementProperties::LongitudinalEndPosition() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4::IfcSectionReinforcementProperties::setLongitudinalEndPosition(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcSectionReinforcementProperties::TransversePosition() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4::IfcReinforcingBarRoleEnum::Value Ifc4::IfcSectionReinforcementProperties::ReinforcementRole() const {  return ::Ifc4::IfcReinforcingBarRoleEnum::FromString(*data_->getArgument(3)); }
 void Ifc4::IfcSectionReinforcementProperties::setReinforcementRole(::Ifc4::IfcReinforcingBarRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcReinforcingBarRoleEnum::ToString(v)));data_->setArgument(3,attr);} }
 ::Ifc4::IfcSectionProperties* Ifc4::IfcSectionReinforcementProperties::SectionDefinition() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4::IfcSectionProperties>(true); }
@@ -18175,7 +18175,7 @@ Ifc4::IfcSectionedSpine::IfcSectionedSpine(::Ifc4::IfcCompositeCurve* v1_SpineCu
 
 // Function implementations for IfcSensor
 boost::optional< ::Ifc4::IfcSensorTypeEnum::Value > Ifc4::IfcSensor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcSensorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcSensor::setPredefinedType(boost::optional< ::Ifc4::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSensorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcSensor::setPredefinedType(boost::optional< ::Ifc4::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSensorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSensor::declaration() const { return *IFC4_IfcSensor_type; }
@@ -18195,7 +18195,7 @@ Ifc4::IfcSensorType::IfcSensorType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHist
 
 // Function implementations for IfcShadingDevice
 boost::optional< ::Ifc4::IfcShadingDeviceTypeEnum::Value > Ifc4::IfcShadingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcShadingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcShadingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcShadingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcShadingDevice::declaration() const { return *IFC4_IfcShadingDevice_type; }
@@ -18217,9 +18217,9 @@ Ifc4::IfcShadingDeviceType::IfcShadingDeviceType(std::string v1_GlobalId, ::Ifc4
 aggregate_of< ::Ifc4::IfcShapeModel >::ptr Ifc4::IfcShapeAspect::ShapeRepresentations() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4::IfcShapeModel >(); }
 void Ifc4::IfcShapeAspect::setShapeRepresentations(aggregate_of< ::Ifc4::IfcShapeModel >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcShapeAspect::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcShapeAspect::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::logic::tribool Ifc4::IfcShapeAspect::ProductDefinitional() const {  boost::logic::tribool v = *data_->getArgument(3); return v; }
 void Ifc4::IfcShapeAspect::setProductDefinitional(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4::IfcProductRepresentationSelect* Ifc4::IfcShapeAspect::PartOfProductDefinitionShape() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4::IfcProductRepresentationSelect>(true); }
@@ -18268,11 +18268,11 @@ Ifc4::IfcSimpleProperty::IfcSimpleProperty(std::string v1_Name, boost::optional<
 
 // Function implementations for IfcSimplePropertyTemplate
 boost::optional< ::Ifc4::IfcSimplePropertyTemplateTypeEnum::Value > Ifc4::IfcSimplePropertyTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4::IfcSimplePropertyTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcSimplePropertyTemplate::PrimaryMeasureType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcSimplePropertyTemplate::SecondaryMeasureType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4::IfcPropertyEnumeration* Ifc4::IfcSimplePropertyTemplate::Enumerators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4::IfcPropertyEnumeration>(true); }
 void Ifc4::IfcSimplePropertyTemplate::setEnumerators(::Ifc4::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4::IfcUnit* Ifc4::IfcSimplePropertyTemplate::PrimaryUnit() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4::IfcUnit>(true); }
@@ -18280,9 +18280,9 @@ void Ifc4::IfcSimplePropertyTemplate::setPrimaryUnit(::Ifc4::IfcUnit* v) { {IfcW
 ::Ifc4::IfcUnit* Ifc4::IfcSimplePropertyTemplate::SecondaryUnit() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4::IfcUnit>(true); }
 void Ifc4::IfcSimplePropertyTemplate::setSecondaryUnit(::Ifc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4::IfcSimplePropertyTemplate::Expression() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4::IfcStateEnum::Value > Ifc4::IfcSimplePropertyTemplate::AccessState() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4::IfcStateEnum::FromString(*data_->getArgument(11)); }
-void Ifc4::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcStateEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcStateEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSimplePropertyTemplate::declaration() const { return *IFC4_IfcSimplePropertyTemplate_type; }
@@ -18292,13 +18292,13 @@ Ifc4::IfcSimplePropertyTemplate::IfcSimplePropertyTemplate(std::string v1_Global
 
 // Function implementations for IfcSite
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4::IfcSite::RefLatitude() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(9); return v; }
-void Ifc4::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4::IfcSite::RefLongitude() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(10); return v; }
-void Ifc4::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcSite::RefElevation() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4::IfcSite::LandTitleNumber() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4::IfcPostalAddress* Ifc4::IfcSite::SiteAddress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4::IfcPostalAddress>(true); }
 void Ifc4::IfcSite::setSiteAddress(::Ifc4::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -18310,7 +18310,7 @@ Ifc4::IfcSite::IfcSite(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Owne
 
 // Function implementations for IfcSlab
 boost::optional< ::Ifc4::IfcSlabTypeEnum::Value > Ifc4::IfcSlab::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcSlabTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcSlab::setPredefinedType(boost::optional< ::Ifc4::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSlabTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcSlab::setPredefinedType(boost::optional< ::Ifc4::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSlabTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSlab::declaration() const { return *IFC4_IfcSlab_type; }
@@ -18346,11 +18346,11 @@ Ifc4::IfcSlabType::IfcSlabType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory*
 
 // Function implementations for IfcSlippageConnectionCondition
 boost::optional< double > Ifc4::IfcSlippageConnectionCondition::SlippageX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcSlippageConnectionCondition::SlippageY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcSlippageConnectionCondition::SlippageZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSlippageConnectionCondition::declaration() const { return *IFC4_IfcSlippageConnectionCondition_type; }
@@ -18360,7 +18360,7 @@ Ifc4::IfcSlippageConnectionCondition::IfcSlippageConnectionCondition(boost::opti
 
 // Function implementations for IfcSolarDevice
 boost::optional< ::Ifc4::IfcSolarDeviceTypeEnum::Value > Ifc4::IfcSolarDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcSolarDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSolarDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSolarDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSolarDevice::declaration() const { return *IFC4_IfcSolarDevice_type; }
@@ -18388,9 +18388,9 @@ Ifc4::IfcSolidModel::IfcSolidModel() : IfcGeometricRepresentationItem((IfcEntity
 
 // Function implementations for IfcSpace
 boost::optional< ::Ifc4::IfcSpaceTypeEnum::Value > Ifc4::IfcSpace::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4::IfcSpace::setPredefinedType(boost::optional< ::Ifc4::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSpaceTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4::IfcSpace::setPredefinedType(boost::optional< ::Ifc4::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSpaceTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcSpace::ElevationWithFlooring() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 ::Ifc4::IfcRelCoversSpaces::list::ptr Ifc4::IfcSpace::HasCoverings() const { return data_->getInverse(IFC4_IfcRelCoversSpaces_type, 4)->as<IfcRelCoversSpaces>(); }
 ::Ifc4::IfcRelSpaceBoundary::list::ptr Ifc4::IfcSpace::BoundedBy() const { return data_->getInverse(IFC4_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
@@ -18402,7 +18402,7 @@ Ifc4::IfcSpace::IfcSpace(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Ow
 
 // Function implementations for IfcSpaceHeater
 boost::optional< ::Ifc4::IfcSpaceHeaterTypeEnum::Value > Ifc4::IfcSpaceHeater::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcSpaceHeaterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSpaceHeaterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSpaceHeaterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSpaceHeater::declaration() const { return *IFC4_IfcSpaceHeater_type; }
@@ -18424,7 +18424,7 @@ Ifc4::IfcSpaceHeaterType::IfcSpaceHeaterType(std::string v1_GlobalId, ::Ifc4::If
 ::Ifc4::IfcSpaceTypeEnum::Value Ifc4::IfcSpaceType::PredefinedType() const {  return ::Ifc4::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4::IfcSpaceType::setPredefinedType(::Ifc4::IfcSpaceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcSpaceTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4::IfcSpaceType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSpaceType::declaration() const { return *IFC4_IfcSpaceType_type; }
@@ -18434,7 +18434,7 @@ Ifc4::IfcSpaceType::IfcSpaceType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistor
 
 // Function implementations for IfcSpatialElement
 boost::optional< std::string > Ifc4::IfcSpatialElement::LongName() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4::IfcRelContainedInSpatialStructure::list::ptr Ifc4::IfcSpatialElement::ContainsElements() const { return data_->getInverse(IFC4_IfcRelContainedInSpatialStructure_type, 5)->as<IfcRelContainedInSpatialStructure>(); }
 ::Ifc4::IfcRelServicesBuildings::list::ptr Ifc4::IfcSpatialElement::ServicedBySystems() const { return data_->getInverse(IFC4_IfcRelServicesBuildings_type, 5)->as<IfcRelServicesBuildings>(); }
@@ -18447,7 +18447,7 @@ Ifc4::IfcSpatialElement::IfcSpatialElement(std::string v1_GlobalId, ::Ifc4::IfcO
 
 // Function implementations for IfcSpatialElementType
 boost::optional< std::string > Ifc4::IfcSpatialElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSpatialElementType::declaration() const { return *IFC4_IfcSpatialElementType_type; }
@@ -18457,7 +18457,7 @@ Ifc4::IfcSpatialElementType::IfcSpatialElementType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcSpatialStructureElement
 boost::optional< ::Ifc4::IfcElementCompositionEnum::Value > Ifc4::IfcSpatialStructureElement::CompositionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcElementCompositionEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElementCompositionEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcElementCompositionEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSpatialStructureElement::declaration() const { return *IFC4_IfcSpatialStructureElement_type; }
@@ -18475,7 +18475,7 @@ Ifc4::IfcSpatialStructureElementType::IfcSpatialStructureElementType(std::string
 
 // Function implementations for IfcSpatialZone
 boost::optional< ::Ifc4::IfcSpatialZoneTypeEnum::Value > Ifc4::IfcSpatialZone::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSpatialZoneTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSpatialZoneTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSpatialZone::declaration() const { return *IFC4_IfcSpatialZone_type; }
@@ -18487,7 +18487,7 @@ Ifc4::IfcSpatialZone::IfcSpatialZone(std::string v1_GlobalId, ::Ifc4::IfcOwnerHi
 ::Ifc4::IfcSpatialZoneTypeEnum::Value Ifc4::IfcSpatialZoneType::PredefinedType() const {  return ::Ifc4::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4::IfcSpatialZoneType::setPredefinedType(::Ifc4::IfcSpatialZoneTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcSpatialZoneTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4::IfcSpatialZoneType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSpatialZoneType::declaration() const { return *IFC4_IfcSpatialZoneType_type; }
@@ -18517,7 +18517,7 @@ Ifc4::IfcSphericalSurface::IfcSphericalSurface(::Ifc4::IfcAxis2Placement3D* v1_P
 
 // Function implementations for IfcStackTerminal
 boost::optional< ::Ifc4::IfcStackTerminalTypeEnum::Value > Ifc4::IfcStackTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcStackTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcStackTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcStackTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStackTerminal::declaration() const { return *IFC4_IfcStackTerminal_type; }
@@ -18537,7 +18537,7 @@ Ifc4::IfcStackTerminalType::IfcStackTerminalType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcStair
 boost::optional< ::Ifc4::IfcStairTypeEnum::Value > Ifc4::IfcStair::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcStairTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcStair::setPredefinedType(boost::optional< ::Ifc4::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcStairTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcStair::setPredefinedType(boost::optional< ::Ifc4::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcStairTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStair::declaration() const { return *IFC4_IfcStair_type; }
@@ -18547,15 +18547,15 @@ Ifc4::IfcStair::IfcStair(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Ow
 
 // Function implementations for IfcStairFlight
 boost::optional< int > Ifc4::IfcStairFlight::NumberOfRisers() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } int v = *data_->getArgument(8); return v; }
-void Ifc4::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< int > Ifc4::IfcStairFlight::NumberOfTreads() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } int v = *data_->getArgument(9); return v; }
-void Ifc4::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcStairFlight::RiserHeight() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcStairFlight::TreadLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4::IfcStairFlightTypeEnum::Value > Ifc4::IfcStairFlight::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4::IfcStairFlightTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcStairFlightTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcStairFlightTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStairFlight::declaration() const { return *IFC4_IfcStairFlight_type; }
@@ -18585,7 +18585,7 @@ Ifc4::IfcStairType::IfcStairType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistor
 
 // Function implementations for IfcStructuralAction
 boost::optional< bool > Ifc4::IfcStructuralAction::DestabilizingLoad() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralAction::declaration() const { return *IFC4_IfcStructuralAction_type; }
@@ -18612,9 +18612,9 @@ void Ifc4::IfcStructuralAnalysisModel::setPredefinedType(::Ifc4::IfcAnalysisMode
 ::Ifc4::IfcAxis2Placement3D* Ifc4::IfcStructuralAnalysisModel::OrientationOf2DPlane() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcAxis2Placement3D>(true); }
 void Ifc4::IfcStructuralAnalysisModel::setOrientationOf2DPlane(::Ifc4::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcStructuralLoadGroup >::ptr > Ifc4::IfcStructuralAnalysisModel::LoadedBy() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4::IfcStructuralLoadGroup >(); }
-void Ifc4::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcStructuralResultGroup >::ptr > Ifc4::IfcStructuralAnalysisModel::HasResults() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4::IfcStructuralResultGroup >(); }
-void Ifc4::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4::IfcObjectPlacement* Ifc4::IfcStructuralAnalysisModel::SharedPlacement() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4::IfcObjectPlacement>(true); }
 void Ifc4::IfcStructuralAnalysisModel::setSharedPlacement(::Ifc4::IfcObjectPlacement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -18637,7 +18637,7 @@ Ifc4::IfcStructuralConnection::IfcStructuralConnection(std::string v1_GlobalId,
 
 // Function implementations for IfcStructuralConnectionCondition
 boost::optional< std::string > Ifc4::IfcStructuralConnectionCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralConnectionCondition::declaration() const { return *IFC4_IfcStructuralConnectionCondition_type; }
@@ -18647,7 +18647,7 @@ Ifc4::IfcStructuralConnectionCondition::IfcStructuralConnectionCondition(boost::
 
 // Function implementations for IfcStructuralCurveAction
 boost::optional< ::Ifc4::IfcProjectedOrTrueLengthEnum::Value > Ifc4::IfcStructuralCurveAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4::IfcStructuralCurveActivityTypeEnum::Value Ifc4::IfcStructuralCurveAction::PredefinedType() const {  return ::Ifc4::IfcStructuralCurveActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4::IfcStructuralCurveAction::setPredefinedType(::Ifc4::IfcStructuralCurveActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcStructuralCurveActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -18716,7 +18716,7 @@ Ifc4::IfcStructuralLinearAction::IfcStructuralLinearAction(std::string v1_Global
 
 // Function implementations for IfcStructuralLoad
 boost::optional< std::string > Ifc4::IfcStructuralLoad::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralLoad::declaration() const { return *IFC4_IfcStructuralLoad_type; }
@@ -18726,7 +18726,7 @@ Ifc4::IfcStructuralLoad::IfcStructuralLoad(boost::optional< std::string > v1_Nam
 
 // Function implementations for IfcStructuralLoadCase
 boost::optional< std::vector< double > /*[3:3]*/ > Ifc4::IfcStructuralLoadCase::SelfWeightCoefficients() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< double > /*[3:3]*/ v = *data_->getArgument(10); return v; }
-void Ifc4::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralLoadCase::declaration() const { return *IFC4_IfcStructuralLoadCase_type; }
@@ -18738,7 +18738,7 @@ Ifc4::IfcStructuralLoadCase::IfcStructuralLoadCase(std::string v1_GlobalId, ::If
 aggregate_of< ::Ifc4::IfcStructuralLoadOrResult >::ptr Ifc4::IfcStructuralLoadConfiguration::Values() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4::IfcStructuralLoadOrResult >(); }
 void Ifc4::IfcStructuralLoadConfiguration::setValues(aggregate_of< ::Ifc4::IfcStructuralLoadOrResult >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::vector< std::vector< double > > > Ifc4::IfcStructuralLoadConfiguration::Locations() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(2); return v; }
-void Ifc4::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralLoadConfiguration::declaration() const { return *IFC4_IfcStructuralLoadConfiguration_type; }
@@ -18754,9 +18754,9 @@ void Ifc4::IfcStructuralLoadGroup::setActionType(::Ifc4::IfcActionTypeEnum::Valu
 ::Ifc4::IfcActionSourceTypeEnum::Value Ifc4::IfcStructuralLoadGroup::ActionSource() const {  return ::Ifc4::IfcActionSourceTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4::IfcStructuralLoadGroup::setActionSource(::Ifc4::IfcActionSourceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcActionSourceTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadGroup::Coefficient() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4::IfcStructuralLoadGroup::Purpose() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 ::Ifc4::IfcStructuralResultGroup::list::ptr Ifc4::IfcStructuralLoadGroup::SourceOfResultGroup() const { return data_->getInverse(IFC4_IfcStructuralResultGroup_type, 6)->as<IfcStructuralResultGroup>(); }
 ::Ifc4::IfcStructuralAnalysisModel::list::ptr Ifc4::IfcStructuralLoadGroup::LoadGroupFor() const { return data_->getInverse(IFC4_IfcStructuralAnalysisModel_type, 7)->as<IfcStructuralAnalysisModel>(); }
@@ -18768,17 +18768,17 @@ Ifc4::IfcStructuralLoadGroup::IfcStructuralLoadGroup(std::string v1_GlobalId, ::
 
 // Function implementations for IfcStructuralLoadLinearForce
 boost::optional< double > Ifc4::IfcStructuralLoadLinearForce::LinearForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadLinearForce::LinearForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadLinearForce::LinearForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadLinearForce::LinearMomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadLinearForce::LinearMomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadLinearForce::LinearMomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralLoadLinearForce::declaration() const { return *IFC4_IfcStructuralLoadLinearForce_type; }
@@ -18796,11 +18796,11 @@ Ifc4::IfcStructuralLoadOrResult::IfcStructuralLoadOrResult(boost::optional< std:
 
 // Function implementations for IfcStructuralLoadPlanarForce
 boost::optional< double > Ifc4::IfcStructuralLoadPlanarForce::PlanarForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadPlanarForce::PlanarForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadPlanarForce::PlanarForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralLoadPlanarForce::declaration() const { return *IFC4_IfcStructuralLoadPlanarForce_type; }
@@ -18810,17 +18810,17 @@ Ifc4::IfcStructuralLoadPlanarForce::IfcStructuralLoadPlanarForce(boost::optional
 
 // Function implementations for IfcStructuralLoadSingleDisplacement
 boost::optional< double > Ifc4::IfcStructuralLoadSingleDisplacement::DisplacementX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadSingleDisplacement::DisplacementY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadSingleDisplacement::DisplacementZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralLoadSingleDisplacement::declaration() const { return *IFC4_IfcStructuralLoadSingleDisplacement_type; }
@@ -18830,7 +18830,7 @@ Ifc4::IfcStructuralLoadSingleDisplacement::IfcStructuralLoadSingleDisplacement(b
 
 // Function implementations for IfcStructuralLoadSingleDisplacementDistortion
 boost::optional< double > Ifc4::IfcStructuralLoadSingleDisplacementDistortion::Distortion() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralLoadSingleDisplacementDistortion::declaration() const { return *IFC4_IfcStructuralLoadSingleDisplacementDistortion_type; }
@@ -18840,17 +18840,17 @@ Ifc4::IfcStructuralLoadSingleDisplacementDistortion::IfcStructuralLoadSingleDisp
 
 // Function implementations for IfcStructuralLoadSingleForce
 boost::optional< double > Ifc4::IfcStructuralLoadSingleForce::ForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadSingleForce::ForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadSingleForce::ForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadSingleForce::MomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadSingleForce::MomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadSingleForce::MomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralLoadSingleForce::declaration() const { return *IFC4_IfcStructuralLoadSingleForce_type; }
@@ -18860,7 +18860,7 @@ Ifc4::IfcStructuralLoadSingleForce::IfcStructuralLoadSingleForce(boost::optional
 
 // Function implementations for IfcStructuralLoadSingleForceWarping
 boost::optional< double > Ifc4::IfcStructuralLoadSingleForceWarping::WarpingMoment() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralLoadSingleForceWarping::declaration() const { return *IFC4_IfcStructuralLoadSingleForceWarping_type; }
@@ -18878,11 +18878,11 @@ Ifc4::IfcStructuralLoadStatic::IfcStructuralLoadStatic(boost::optional< std::str
 
 // Function implementations for IfcStructuralLoadTemperature
 boost::optional< double > Ifc4::IfcStructuralLoadTemperature::DeltaTConstant() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadTemperature::DeltaTY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcStructuralLoadTemperature::DeltaTZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralLoadTemperature::declaration() const { return *IFC4_IfcStructuralLoadTemperature_type; }
@@ -18958,7 +18958,7 @@ Ifc4::IfcStructuralResultGroup::IfcStructuralResultGroup(std::string v1_GlobalId
 
 // Function implementations for IfcStructuralSurfaceAction
 boost::optional< ::Ifc4::IfcProjectedOrTrueLengthEnum::Value > Ifc4::IfcStructuralSurfaceAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4::IfcStructuralSurfaceActivityTypeEnum::Value Ifc4::IfcStructuralSurfaceAction::PredefinedType() const {  return ::Ifc4::IfcStructuralSurfaceActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4::IfcStructuralSurfaceAction::setPredefinedType(::Ifc4::IfcStructuralSurfaceActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcStructuralSurfaceActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -18980,7 +18980,7 @@ Ifc4::IfcStructuralSurfaceConnection::IfcStructuralSurfaceConnection(std::string
 ::Ifc4::IfcStructuralSurfaceMemberTypeEnum::Value Ifc4::IfcStructuralSurfaceMember::PredefinedType() const {  return ::Ifc4::IfcStructuralSurfaceMemberTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4::IfcStructuralSurfaceMember::setPredefinedType(::Ifc4::IfcStructuralSurfaceMemberTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcStructuralSurfaceMemberTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4::IfcStructuralSurfaceMember::Thickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStructuralSurfaceMember::declaration() const { return *IFC4_IfcStructuralSurfaceMember_type; }
@@ -19020,7 +19020,7 @@ void Ifc4::IfcStyledItem::setItem(::Ifc4::IfcRepresentationItem* v) { {IfcWrite:
 aggregate_of_instance::ptr Ifc4::IfcStyledItem::Styles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4::IfcStyledItem::setStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcStyledItem::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcStyledItem::declaration() const { return *IFC4_IfcStyledItem_type; }
@@ -19038,7 +19038,7 @@ Ifc4::IfcStyledRepresentation::IfcStyledRepresentation(::Ifc4::IfcRepresentation
 
 // Function implementations for IfcSubContractResource
 boost::optional< ::Ifc4::IfcSubContractResourceTypeEnum::Value > Ifc4::IfcSubContractResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcSubContractResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSubContractResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSubContractResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSubContractResource::declaration() const { return *IFC4_IfcSubContractResource_type; }
@@ -19092,9 +19092,9 @@ Ifc4::IfcSurfaceCurve::IfcSurfaceCurve(::Ifc4::IfcCurve* v1_Curve3D, aggregate_o
 ::Ifc4::IfcCurve* Ifc4::IfcSurfaceCurveSweptAreaSolid::Directrix() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4::IfcCurve>(true); }
 void Ifc4::IfcSurfaceCurveSweptAreaSolid::setDirectrix(::Ifc4::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcSurfaceCurveSweptAreaSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcSurfaceCurveSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcSurfaceCurveSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcSurfaceCurveSweptAreaSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcSurfaceCurveSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcSurfaceCurveSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4::IfcSurface* Ifc4::IfcSurfaceCurveSweptAreaSolid::ReferenceSurface() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4::IfcSurface>(true); }
 void Ifc4::IfcSurfaceCurveSweptAreaSolid::setReferenceSurface(::Ifc4::IfcSurface* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -19106,7 +19106,7 @@ Ifc4::IfcSurfaceCurveSweptAreaSolid::IfcSurfaceCurveSweptAreaSolid(::Ifc4::IfcPr
 
 // Function implementations for IfcSurfaceFeature
 boost::optional< ::Ifc4::IfcSurfaceFeatureTypeEnum::Value > Ifc4::IfcSurfaceFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcSurfaceFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSurfaceFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSurfaceFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSurfaceFeature::declaration() const { return *IFC4_IfcSurfaceFeature_type; }
@@ -19138,11 +19138,11 @@ Ifc4::IfcSurfaceOfRevolution::IfcSurfaceOfRevolution(::Ifc4::IfcProfileDef* v1_S
 
 // Function implementations for IfcSurfaceReinforcementArea
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4::IfcSurfaceReinforcementArea::SurfaceReinforcement1() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(1); return v; }
-void Ifc4::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4::IfcSurfaceReinforcementArea::SurfaceReinforcement2() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(2); return v; }
-void Ifc4::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcSurfaceReinforcementArea::ShearReinforcement() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSurfaceReinforcementArea::declaration() const { return *IFC4_IfcSurfaceReinforcementArea_type; }
@@ -19180,9 +19180,9 @@ Ifc4::IfcSurfaceStyleLighting::IfcSurfaceStyleLighting(::Ifc4::IfcColourRgb* v1_
 
 // Function implementations for IfcSurfaceStyleRefraction
 boost::optional< double > Ifc4::IfcSurfaceStyleRefraction::RefractionIndex() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc4::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4::IfcSurfaceStyleRefraction::DispersionFactor() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSurfaceStyleRefraction::declaration() const { return *IFC4_IfcSurfaceStyleRefraction_type; }
@@ -19216,7 +19216,7 @@ Ifc4::IfcSurfaceStyleRendering::IfcSurfaceStyleRendering(::Ifc4::IfcColourRgb* v
 ::Ifc4::IfcColourRgb* Ifc4::IfcSurfaceStyleShading::SurfaceColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4::IfcColourRgb>(true); }
 void Ifc4::IfcSurfaceStyleShading::setSurfaceColour(::Ifc4::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4::IfcSurfaceStyleShading::Transparency() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSurfaceStyleShading::declaration() const { return *IFC4_IfcSurfaceStyleShading_type; }
@@ -19240,11 +19240,11 @@ void Ifc4::IfcSurfaceTexture::setRepeatS(bool v) { {IfcWrite::IfcWriteArgument*
 bool Ifc4::IfcSurfaceTexture::RepeatT() const {  bool v = *data_->getArgument(1); return v; }
 void Ifc4::IfcSurfaceTexture::setRepeatT(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcSurfaceTexture::Mode() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4::IfcCartesianTransformationOperator2D* Ifc4::IfcSurfaceTexture::TextureTransform() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4::IfcSurfaceTexture::setTextureTransform(::Ifc4::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4::IfcSurfaceTexture::Parameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4::IfcTextureCoordinate::list::ptr Ifc4::IfcSurfaceTexture::IsMappedBy() const { return data_->getInverse(IFC4_IfcTextureCoordinate_type, 0)->as<IfcTextureCoordinate>(); }
 ::Ifc4::IfcSurfaceStyleWithTextures::list::ptr Ifc4::IfcSurfaceTexture::UsedInStyles() const { return data_->getInverse(IFC4_IfcSurfaceStyleWithTextures_type, 0)->as<IfcSurfaceStyleWithTextures>(); }
@@ -19272,11 +19272,11 @@ void Ifc4::IfcSweptDiskSolid::setDirectrix(::Ifc4::IfcCurve* v) { {IfcWrite::Ifc
 double Ifc4::IfcSweptDiskSolid::Radius() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4::IfcSweptDiskSolid::setRadius(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4::IfcSweptDiskSolid::InnerRadius() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4::IfcSweptDiskSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4::IfcSweptDiskSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSweptDiskSolid::declaration() const { return *IFC4_IfcSweptDiskSolid_type; }
@@ -19286,7 +19286,7 @@ Ifc4::IfcSweptDiskSolid::IfcSweptDiskSolid(::Ifc4::IfcCurve* v1_Directrix, doubl
 
 // Function implementations for IfcSweptDiskSolidPolygonal
 boost::optional< double > Ifc4::IfcSweptDiskSolidPolygonal::FilletRadius() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSweptDiskSolidPolygonal::declaration() const { return *IFC4_IfcSweptDiskSolidPolygonal_type; }
@@ -19308,7 +19308,7 @@ Ifc4::IfcSweptSurface::IfcSweptSurface(::Ifc4::IfcProfileDef* v1_SweptCurve, ::I
 
 // Function implementations for IfcSwitchingDevice
 boost::optional< ::Ifc4::IfcSwitchingDeviceTypeEnum::Value > Ifc4::IfcSwitchingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcSwitchingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSwitchingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSwitchingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSwitchingDevice::declaration() const { return *IFC4_IfcSwitchingDevice_type; }
@@ -19337,7 +19337,7 @@ Ifc4::IfcSystem::IfcSystem(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_
 
 // Function implementations for IfcSystemFurnitureElement
 boost::optional< ::Ifc4::IfcSystemFurnitureElementTypeEnum::Value > Ifc4::IfcSystemFurnitureElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSystemFurnitureElement::declaration() const { return *IFC4_IfcSystemFurnitureElement_type; }
@@ -19347,7 +19347,7 @@ Ifc4::IfcSystemFurnitureElement::IfcSystemFurnitureElement(std::string v1_Global
 
 // Function implementations for IfcSystemFurnitureElementType
 boost::optional< ::Ifc4::IfcSystemFurnitureElementTypeEnum::Value > Ifc4::IfcSystemFurnitureElementType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcSystemFurnitureElementType::declaration() const { return *IFC4_IfcSystemFurnitureElementType_type; }
@@ -19365,15 +19365,15 @@ void Ifc4::IfcTShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWriteA
 double Ifc4::IfcTShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4::IfcTShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcTShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4::IfcTShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4::IfcTShapeProfileDef::WebEdgeRadius() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcTShapeProfileDef::WebSlope() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcTShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTShapeProfileDef::declaration() const { return *IFC4_IfcTShapeProfileDef_type; }
@@ -19383,11 +19383,11 @@ Ifc4::IfcTShapeProfileDef::IfcTShapeProfileDef(::Ifc4::IfcProfileTypeEnum::Value
 
 // Function implementations for IfcTable
 boost::optional< std::string > Ifc4::IfcTable::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcTableRow >::ptr > Ifc4::IfcTable::Rows() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4::IfcTableRow >(); }
-void Ifc4::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcTableColumn >::ptr > Ifc4::IfcTable::Columns() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4::IfcTableColumn >(); }
-void Ifc4::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTable::declaration() const { return *IFC4_IfcTable_type; }
@@ -19397,11 +19397,11 @@ Ifc4::IfcTable::IfcTable(boost::optional< std::string > v1_Name, boost::optional
 
 // Function implementations for IfcTableColumn
 boost::optional< std::string > Ifc4::IfcTableColumn::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcTableColumn::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcTableColumn::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4::IfcUnit* Ifc4::IfcTableColumn::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcUnit>(true); }
 void Ifc4::IfcTableColumn::setUnit(::Ifc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4::IfcReference* Ifc4::IfcTableColumn::ReferencePath() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4::IfcReference>(true); }
@@ -19415,9 +19415,9 @@ Ifc4::IfcTableColumn::IfcTableColumn(boost::optional< std::string > v1_Identifie
 
 // Function implementations for IfcTableRow
 boost::optional< aggregate_of_instance::ptr > Ifc4::IfcTableRow::RowCells() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(0); return v; }
-void Ifc4::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< bool > Ifc4::IfcTableRow::IsHeading() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTableRow::declaration() const { return *IFC4_IfcTableRow_type; }
@@ -19427,7 +19427,7 @@ Ifc4::IfcTableRow::IfcTableRow(boost::optional< aggregate_of_instance::ptr > v1_
 
 // Function implementations for IfcTank
 boost::optional< ::Ifc4::IfcTankTypeEnum::Value > Ifc4::IfcTank::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcTankTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcTank::setPredefinedType(boost::optional< ::Ifc4::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTankTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcTank::setPredefinedType(boost::optional< ::Ifc4::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTankTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTank::declaration() const { return *IFC4_IfcTank_type; }
@@ -19447,17 +19447,17 @@ Ifc4::IfcTankType::IfcTankType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory*
 
 // Function implementations for IfcTask
 boost::optional< std::string > Ifc4::IfcTask::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcTask::WorkMethod() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 bool Ifc4::IfcTask::IsMilestone() const {  bool v = *data_->getArgument(9); return v; }
 void Ifc4::IfcTask::setIsMilestone(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< int > Ifc4::IfcTask::Priority() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } int v = *data_->getArgument(10); return v; }
-void Ifc4::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4::IfcTaskTime* Ifc4::IfcTask::TaskTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4::IfcTaskTime>(true); }
 void Ifc4::IfcTask::setTaskTime(::Ifc4::IfcTaskTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4::IfcTaskTypeEnum::Value > Ifc4::IfcTask::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4::IfcTaskTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4::IfcTask::setPredefinedType(boost::optional< ::Ifc4::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTaskTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4::IfcTask::setPredefinedType(boost::optional< ::Ifc4::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTaskTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTask::declaration() const { return *IFC4_IfcTask_type; }
@@ -19467,39 +19467,39 @@ Ifc4::IfcTask::IfcTask(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_Owne
 
 // Function implementations for IfcTaskTime
 boost::optional< ::Ifc4::IfcTaskDurationEnum::Value > Ifc4::IfcTaskTime::DurationType() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4::IfcTaskDurationEnum::FromString(*data_->getArgument(3)); }
-void Ifc4::IfcTaskTime::setDurationType(boost::optional< ::Ifc4::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTaskDurationEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4::IfcTaskTime::setDurationType(boost::optional< ::Ifc4::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTaskDurationEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::ScheduleDuration() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::EarlyStart() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::EarlyFinish() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::LateStart() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::LateFinish() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::FreeFloat() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::TotalFloat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< bool > Ifc4::IfcTaskTime::IsCritical() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } bool v = *data_->getArgument(13); return v; }
-void Ifc4::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::StatusTime() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::ActualDuration() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::ActualStart() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } std::string v = *data_->getArgument(16); return v; }
-void Ifc4::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::ActualFinish() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } std::string v = *data_->getArgument(17); return v; }
-void Ifc4::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskTime::RemainingTime() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< double > Ifc4::IfcTaskTime::Completion() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } double v = *data_->getArgument(19); return v; }
-void Ifc4::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTaskTime::declaration() const { return *IFC4_IfcTaskTime_type; }
@@ -19521,7 +19521,7 @@ Ifc4::IfcTaskTimeRecurring::IfcTaskTimeRecurring(boost::optional< std::string >
 ::Ifc4::IfcTaskTypeEnum::Value Ifc4::IfcTaskType::PredefinedType() const {  return ::Ifc4::IfcTaskTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4::IfcTaskType::setPredefinedType(::Ifc4::IfcTaskTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcTaskTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4::IfcTaskType::WorkMethod() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTaskType::declaration() const { return *IFC4_IfcTaskType_type; }
@@ -19531,17 +19531,17 @@ Ifc4::IfcTaskType::IfcTaskType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory*
 
 // Function implementations for IfcTelecomAddress
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4::IfcTelecomAddress::TelephoneNumbers() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4::IfcTelecomAddress::FacsimileNumbers() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcTelecomAddress::PagerNumber() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4::IfcTelecomAddress::ElectronicMailAddresses() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcTelecomAddress::WWWHomePageURL() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4::IfcTelecomAddress::MessagingIDs() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(8); return v; }
-void Ifc4::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTelecomAddress::declaration() const { return *IFC4_IfcTelecomAddress_type; }
@@ -19551,21 +19551,21 @@ Ifc4::IfcTelecomAddress::IfcTelecomAddress(boost::optional< ::Ifc4::IfcAddressTy
 
 // Function implementations for IfcTendon
 boost::optional< ::Ifc4::IfcTendonTypeEnum::Value > Ifc4::IfcTendon::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4::IfcTendon::setPredefinedType(boost::optional< ::Ifc4::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTendonTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4::IfcTendon::setPredefinedType(boost::optional< ::Ifc4::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTendonTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcTendon::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcTendon::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4::IfcTendon::TensionForce() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4::IfcTendon::PreStress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4::IfcTendon::FrictionCoefficient() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4::IfcTendon::AnchorageSlip() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4::IfcTendon::MinCurvatureRadius() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTendon::declaration() const { return *IFC4_IfcTendon_type; }
@@ -19575,7 +19575,7 @@ Ifc4::IfcTendon::IfcTendon(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_
 
 // Function implementations for IfcTendonAnchor
 boost::optional< ::Ifc4::IfcTendonAnchorTypeEnum::Value > Ifc4::IfcTendonAnchor::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4::IfcTendonAnchorTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTendonAnchorTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTendonAnchorTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTendonAnchor::declaration() const { return *IFC4_IfcTendonAnchor_type; }
@@ -19597,11 +19597,11 @@ Ifc4::IfcTendonAnchorType::IfcTendonAnchorType(std::string v1_GlobalId, ::Ifc4::
 ::Ifc4::IfcTendonTypeEnum::Value Ifc4::IfcTendonType::PredefinedType() const {  return ::Ifc4::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4::IfcTendonType::setPredefinedType(::Ifc4::IfcTendonTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcTendonTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcTendonType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcTendonType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4::IfcTendonType::SheathDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTendonType::declaration() const { return *IFC4_IfcTendonType_type; }
@@ -19663,7 +19663,7 @@ void Ifc4::IfcTextStyle::setTextStyle(::Ifc4::IfcTextStyleTextModel* v) { {IfcWr
 ::Ifc4::IfcTextFontSelect* Ifc4::IfcTextStyle::TextFontStyle() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcTextFontSelect>(true); }
 void Ifc4::IfcTextStyle::setTextFontStyle(::Ifc4::IfcTextFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4::IfcTextStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTextStyle::declaration() const { return *IFC4_IfcTextStyle_type; }
@@ -19675,11 +19675,11 @@ Ifc4::IfcTextStyle::IfcTextStyle(boost::optional< std::string > v1_Name, ::Ifc4:
 std::vector< std::string > /*[1:?]*/ Ifc4::IfcTextStyleFontModel::FontFamily() const {  std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
 void Ifc4::IfcTextStyleFontModel::setFontFamily(std::vector< std::string > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcTextStyleFontModel::FontStyle() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4::IfcTextStyleFontModel::FontVariant() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcTextStyleFontModel::FontWeight() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4::IfcSizeSelect* Ifc4::IfcTextStyleFontModel::FontSize() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4::IfcSizeSelect>(true); }
 void Ifc4::IfcTextStyleFontModel::setFontSize(::Ifc4::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -19705,15 +19705,15 @@ Ifc4::IfcTextStyleForDefinedFont::IfcTextStyleForDefinedFont(::Ifc4::IfcColour*
 ::Ifc4::IfcSizeSelect* Ifc4::IfcTextStyleTextModel::TextIndent() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4::IfcSizeSelect>(true); }
 void Ifc4::IfcTextStyleTextModel::setTextIndent(::Ifc4::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcTextStyleTextModel::TextAlign() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4::IfcTextStyleTextModel::TextDecoration() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4::IfcSizeSelect* Ifc4::IfcTextStyleTextModel::LetterSpacing() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcSizeSelect>(true); }
 void Ifc4::IfcTextStyleTextModel::setLetterSpacing(::Ifc4::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4::IfcSizeSelect* Ifc4::IfcTextStyleTextModel::WordSpacing() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4::IfcSizeSelect>(true); }
 void Ifc4::IfcTextStyleTextModel::setWordSpacing(::Ifc4::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcTextStyleTextModel::TextTransform() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4::IfcSizeSelect* Ifc4::IfcTextStyleTextModel::LineHeight() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4::IfcSizeSelect>(true); }
 void Ifc4::IfcTextStyleTextModel::setLineHeight(::Ifc4::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -19737,7 +19737,7 @@ Ifc4::IfcTextureCoordinate::IfcTextureCoordinate(aggregate_of< ::Ifc4::IfcSurfac
 std::string Ifc4::IfcTextureCoordinateGenerator::Mode() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4::IfcTextureCoordinateGenerator::setMode(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[1:?]*/ > Ifc4::IfcTextureCoordinateGenerator::Parameter() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTextureCoordinateGenerator::declaration() const { return *IFC4_IfcTextureCoordinateGenerator_type; }
@@ -19793,7 +19793,7 @@ Ifc4::IfcTimePeriod::IfcTimePeriod(std::string v1_StartTime, std::string v2_EndT
 std::string Ifc4::IfcTimeSeries::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4::IfcTimeSeries::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4::IfcTimeSeries::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 std::string Ifc4::IfcTimeSeries::StartTime() const {  std::string v = *data_->getArgument(2); return v; }
 void Ifc4::IfcTimeSeries::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::string Ifc4::IfcTimeSeries::EndTime() const {  std::string v = *data_->getArgument(3); return v; }
@@ -19803,7 +19803,7 @@ void Ifc4::IfcTimeSeries::setTimeSeriesDataType(::Ifc4::IfcTimeSeriesDataTypeEnu
 ::Ifc4::IfcDataOriginEnum::Value Ifc4::IfcTimeSeries::DataOrigin() const {  return ::Ifc4::IfcDataOriginEnum::FromString(*data_->getArgument(5)); }
 void Ifc4::IfcTimeSeries::setDataOrigin(::Ifc4::IfcDataOriginEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcDataOriginEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4::IfcTimeSeries::UserDefinedDataOrigin() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4::IfcUnit* Ifc4::IfcTimeSeries::Unit() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4::IfcUnit>(true); }
 void Ifc4::IfcTimeSeries::setUnit(::Ifc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 
@@ -19854,7 +19854,7 @@ Ifc4::IfcToroidalSurface::IfcToroidalSurface(::Ifc4::IfcAxis2Placement3D* v1_Pos
 
 // Function implementations for IfcTransformer
 boost::optional< ::Ifc4::IfcTransformerTypeEnum::Value > Ifc4::IfcTransformer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcTransformerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTransformerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTransformerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTransformer::declaration() const { return *IFC4_IfcTransformer_type; }
@@ -19874,7 +19874,7 @@ Ifc4::IfcTransformerType::IfcTransformerType(std::string v1_GlobalId, ::Ifc4::If
 
 // Function implementations for IfcTransportElement
 boost::optional< ::Ifc4::IfcTransportElementTypeEnum::Value > Ifc4::IfcTransportElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcTransportElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcTransportElement::setPredefinedType(boost::optional< ::Ifc4::IfcTransportElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTransportElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcTransportElement::setPredefinedType(boost::optional< ::Ifc4::IfcTransportElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTransportElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTransportElement::declaration() const { return *IFC4_IfcTransportElement_type; }
@@ -19910,13 +19910,13 @@ Ifc4::IfcTrapeziumProfileDef::IfcTrapeziumProfileDef(::Ifc4::IfcProfileTypeEnum:
 
 // Function implementations for IfcTriangulatedFaceSet
 boost::optional< std::vector< std::vector< double > > > Ifc4::IfcTriangulatedFaceSet::Normals() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(1); return v; }
-void Ifc4::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4::IfcTriangulatedFaceSet::Closed() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::vector< std::vector< int > > Ifc4::IfcTriangulatedFaceSet::CoordIndex() const {  std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
 void Ifc4::IfcTriangulatedFaceSet::setCoordIndex(std::vector< std::vector< int > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4::IfcTriangulatedFaceSet::PnIndex() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTriangulatedFaceSet::declaration() const { return *IFC4_IfcTriangulatedFaceSet_type; }
@@ -19944,7 +19944,7 @@ Ifc4::IfcTrimmedCurve::IfcTrimmedCurve(::Ifc4::IfcCurve* v1_BasisCurve, aggregat
 
 // Function implementations for IfcTubeBundle
 boost::optional< ::Ifc4::IfcTubeBundleTypeEnum::Value > Ifc4::IfcTubeBundle::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcTubeBundleTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTubeBundleTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcTubeBundleTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcTubeBundle::declaration() const { return *IFC4_IfcTubeBundle_type; }
@@ -19964,9 +19964,9 @@ Ifc4::IfcTubeBundleType::IfcTubeBundleType(std::string v1_GlobalId, ::Ifc4::IfcO
 
 // Function implementations for IfcTypeObject
 boost::optional< std::string > Ifc4::IfcTypeObject::ApplicableOccurrence() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcPropertySetDefinition >::ptr > Ifc4::IfcTypeObject::HasPropertySets() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4::IfcPropertySetDefinition >(); }
-void Ifc4::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(5,attr);} }
+void Ifc4::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(5,attr);} }
 
 ::Ifc4::IfcRelDefinesByType::list::ptr Ifc4::IfcTypeObject::Types() const { return data_->getInverse(IFC4_IfcRelDefinesByType_type, 5)->as<IfcRelDefinesByType>(); }
 
@@ -19977,11 +19977,11 @@ Ifc4::IfcTypeObject::IfcTypeObject(std::string v1_GlobalId, ::Ifc4::IfcOwnerHist
 
 // Function implementations for IfcTypeProcess
 boost::optional< std::string > Ifc4::IfcTypeProcess::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcTypeProcess::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcTypeProcess::ProcessType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4::IfcRelAssignsToProcess::list::ptr Ifc4::IfcTypeProcess::OperatesOn() const { return data_->getInverse(IFC4_IfcRelAssignsToProcess_type, 6)->as<IfcRelAssignsToProcess>(); }
 
@@ -19992,9 +19992,9 @@ Ifc4::IfcTypeProcess::IfcTypeProcess(std::string v1_GlobalId, ::Ifc4::IfcOwnerHi
 
 // Function implementations for IfcTypeProduct
 boost::optional< aggregate_of< ::Ifc4::IfcRepresentationMap >::ptr > Ifc4::IfcTypeProduct::RepresentationMaps() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4::IfcRepresentationMap >(); }
-void Ifc4::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcTypeProduct::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4::IfcRelAssignsToProduct::list::ptr Ifc4::IfcTypeProduct::ReferencedBy() const { return data_->getInverse(IFC4_IfcRelAssignsToProduct_type, 6)->as<IfcRelAssignsToProduct>(); }
 
@@ -20005,11 +20005,11 @@ Ifc4::IfcTypeProduct::IfcTypeProduct(std::string v1_GlobalId, ::Ifc4::IfcOwnerHi
 
 // Function implementations for IfcTypeResource
 boost::optional< std::string > Ifc4::IfcTypeResource::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4::IfcTypeResource::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcTypeResource::ResourceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4::IfcRelAssignsToResource::list::ptr Ifc4::IfcTypeResource::ResourceOf() const { return data_->getInverse(IFC4_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -20028,11 +20028,11 @@ void Ifc4::IfcUShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWriteA
 double Ifc4::IfcUShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4::IfcUShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcUShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4::IfcUShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4::IfcUShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcUShapeProfileDef::declaration() const { return *IFC4_IfcUShapeProfileDef_type; }
@@ -20052,7 +20052,7 @@ Ifc4::IfcUnitAssignment::IfcUnitAssignment(aggregate_of_instance::ptr v1_Units)
 
 // Function implementations for IfcUnitaryControlElement
 boost::optional< ::Ifc4::IfcUnitaryControlElementTypeEnum::Value > Ifc4::IfcUnitaryControlElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcUnitaryControlElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcUnitaryControlElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcUnitaryControlElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcUnitaryControlElement::declaration() const { return *IFC4_IfcUnitaryControlElement_type; }
@@ -20072,7 +20072,7 @@ Ifc4::IfcUnitaryControlElementType::IfcUnitaryControlElementType(std::string v1_
 
 // Function implementations for IfcUnitaryEquipment
 boost::optional< ::Ifc4::IfcUnitaryEquipmentTypeEnum::Value > Ifc4::IfcUnitaryEquipment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcUnitaryEquipmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcUnitaryEquipmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcUnitaryEquipmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcUnitaryEquipment::declaration() const { return *IFC4_IfcUnitaryEquipment_type; }
@@ -20092,7 +20092,7 @@ Ifc4::IfcUnitaryEquipmentType::IfcUnitaryEquipmentType(std::string v1_GlobalId,
 
 // Function implementations for IfcValve
 boost::optional< ::Ifc4::IfcValveTypeEnum::Value > Ifc4::IfcValve::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcValveTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcValve::setPredefinedType(boost::optional< ::Ifc4::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcValveTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcValve::setPredefinedType(boost::optional< ::Ifc4::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcValveTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcValve::declaration() const { return *IFC4_IfcValve_type; }
@@ -20152,7 +20152,7 @@ Ifc4::IfcVertexPoint::IfcVertexPoint(::Ifc4::IfcPoint* v1_VertexGeometry) : IfcV
 
 // Function implementations for IfcVibrationIsolator
 boost::optional< ::Ifc4::IfcVibrationIsolatorTypeEnum::Value > Ifc4::IfcVibrationIsolator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcVibrationIsolatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcVibrationIsolatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcVibrationIsolatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcVibrationIsolator::declaration() const { return *IFC4_IfcVibrationIsolator_type; }
@@ -20192,7 +20192,7 @@ Ifc4::IfcVirtualGridIntersection::IfcVirtualGridIntersection(aggregate_of< ::Ifc
 
 // Function implementations for IfcVoidingFeature
 boost::optional< ::Ifc4::IfcVoidingFeatureTypeEnum::Value > Ifc4::IfcVoidingFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcVoidingFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcVoidingFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcVoidingFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcVoidingFeature::declaration() const { return *IFC4_IfcVoidingFeature_type; }
@@ -20202,7 +20202,7 @@ Ifc4::IfcVoidingFeature::IfcVoidingFeature(std::string v1_GlobalId, ::Ifc4::IfcO
 
 // Function implementations for IfcWall
 boost::optional< ::Ifc4::IfcWallTypeEnum::Value > Ifc4::IfcWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcWall::setPredefinedType(boost::optional< ::Ifc4::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcWall::setPredefinedType(boost::optional< ::Ifc4::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcWall::declaration() const { return *IFC4_IfcWall_type; }
@@ -20238,7 +20238,7 @@ Ifc4::IfcWallType::IfcWallType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory*
 
 // Function implementations for IfcWasteTerminal
 boost::optional< ::Ifc4::IfcWasteTerminalTypeEnum::Value > Ifc4::IfcWasteTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcWasteTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWasteTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWasteTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcWasteTerminal::declaration() const { return *IFC4_IfcWasteTerminal_type; }
@@ -20258,15 +20258,15 @@ Ifc4::IfcWasteTerminalType::IfcWasteTerminalType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcWindow
 boost::optional< double > Ifc4::IfcWindow::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4::IfcWindow::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4::IfcWindowTypeEnum::Value > Ifc4::IfcWindow::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4::IfcWindowTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4::IfcWindow::setPredefinedType(boost::optional< ::Ifc4::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWindowTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4::IfcWindow::setPredefinedType(boost::optional< ::Ifc4::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWindowTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4::IfcWindowTypePartitioningEnum::Value > Ifc4::IfcWindow::PartitioningType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(11)); }
-void Ifc4::IfcWindow::setPartitioningType(boost::optional< ::Ifc4::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWindowTypePartitioningEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4::IfcWindow::setPartitioningType(boost::optional< ::Ifc4::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWindowTypePartitioningEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4::IfcWindow::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcWindow::declaration() const { return *IFC4_IfcWindow_type; }
@@ -20276,29 +20276,29 @@ Ifc4::IfcWindow::IfcWindow(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory* v2_
 
 // Function implementations for IfcWindowLiningProperties
 boost::optional< double > Ifc4::IfcWindowLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4::IfcWindowLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcWindowLiningProperties::TransomThickness() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcWindowLiningProperties::MullionThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4::IfcWindowLiningProperties::FirstTransomOffset() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4::IfcWindowLiningProperties::SecondTransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4::IfcWindowLiningProperties::FirstMullionOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4::IfcWindowLiningProperties::SecondMullionOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 ::Ifc4::IfcShapeAspect* Ifc4::IfcWindowLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(12)))->as<::Ifc4::IfcShapeAspect>(true); }
 void Ifc4::IfcWindowLiningProperties::setShapeAspectStyle(::Ifc4::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4::IfcWindowLiningProperties::LiningOffset() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4::IfcWindowLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4::IfcWindowLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcWindowLiningProperties::declaration() const { return *IFC4_IfcWindowLiningProperties_type; }
@@ -20312,9 +20312,9 @@ void Ifc4::IfcWindowPanelProperties::setOperationType(::Ifc4::IfcWindowPanelOper
 ::Ifc4::IfcWindowPanelPositionEnum::Value Ifc4::IfcWindowPanelProperties::PanelPosition() const {  return ::Ifc4::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4::IfcWindowPanelProperties::setPanelPosition(::Ifc4::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4::IfcWindowPanelProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcWindowPanelProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4::IfcShapeAspect* Ifc4::IfcWindowPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4::IfcShapeAspect>(true); }
 void Ifc4::IfcWindowPanelProperties::setShapeAspectStyle(::Ifc4::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -20354,9 +20354,9 @@ void Ifc4::IfcWindowType::setPredefinedType(::Ifc4::IfcWindowTypeEnum::Value v)
 ::Ifc4::IfcWindowTypePartitioningEnum::Value Ifc4::IfcWindowType::PartitioningType() const {  return ::Ifc4::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(10)); }
 void Ifc4::IfcWindowType::setPartitioningType(::Ifc4::IfcWindowTypePartitioningEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4::IfcWindowTypePartitioningEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4::IfcWindowType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4::IfcWindowType::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcWindowType::declaration() const { return *IFC4_IfcWindowType_type; }
@@ -20366,11 +20366,11 @@ Ifc4::IfcWindowType::IfcWindowType(std::string v1_GlobalId, ::Ifc4::IfcOwnerHist
 
 // Function implementations for IfcWorkCalendar
 boost::optional< aggregate_of< ::Ifc4::IfcWorkTime >::ptr > Ifc4::IfcWorkCalendar::WorkingTimes() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4::IfcWorkTime >(); }
-void Ifc4::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcWorkTime >::ptr > Ifc4::IfcWorkCalendar::ExceptionTimes() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4::IfcWorkTime >(); }
-void Ifc4::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4::IfcWorkCalendarTypeEnum::Value > Ifc4::IfcWorkCalendar::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4::IfcWorkCalendarTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWorkCalendarTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWorkCalendarTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcWorkCalendar::declaration() const { return *IFC4_IfcWorkCalendar_type; }
@@ -20382,17 +20382,17 @@ Ifc4::IfcWorkCalendar::IfcWorkCalendar(std::string v1_GlobalId, ::Ifc4::IfcOwner
 std::string Ifc4::IfcWorkControl::CreationDate() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4::IfcWorkControl::setCreationDate(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4::IfcPerson >::ptr > Ifc4::IfcWorkControl::Creators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4::IfcPerson >(); }
-void Ifc4::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4::IfcWorkControl::Purpose() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4::IfcWorkControl::Duration() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4::IfcWorkControl::TotalFloat() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 std::string Ifc4::IfcWorkControl::StartTime() const {  std::string v = *data_->getArgument(11); return v; }
 void Ifc4::IfcWorkControl::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4::IfcWorkControl::FinishTime() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcWorkControl::declaration() const { return *IFC4_IfcWorkControl_type; }
@@ -20402,7 +20402,7 @@ Ifc4::IfcWorkControl::IfcWorkControl(std::string v1_GlobalId, ::Ifc4::IfcOwnerHi
 
 // Function implementations for IfcWorkPlan
 boost::optional< ::Ifc4::IfcWorkPlanTypeEnum::Value > Ifc4::IfcWorkPlan::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4::IfcWorkPlanTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWorkPlanTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWorkPlanTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcWorkPlan::declaration() const { return *IFC4_IfcWorkPlan_type; }
@@ -20412,7 +20412,7 @@ Ifc4::IfcWorkPlan::IfcWorkPlan(std::string v1_GlobalId, ::Ifc4::IfcOwnerHistory*
 
 // Function implementations for IfcWorkSchedule
 boost::optional< ::Ifc4::IfcWorkScheduleTypeEnum::Value > Ifc4::IfcWorkSchedule::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4::IfcWorkScheduleTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWorkScheduleTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4::IfcWorkScheduleTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcWorkSchedule::declaration() const { return *IFC4_IfcWorkSchedule_type; }
@@ -20424,9 +20424,9 @@ Ifc4::IfcWorkSchedule::IfcWorkSchedule(std::string v1_GlobalId, ::Ifc4::IfcOwner
 ::Ifc4::IfcRecurrencePattern* Ifc4::IfcWorkTime::RecurrencePattern() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4::IfcRecurrencePattern>(true); }
 void Ifc4::IfcWorkTime::setRecurrencePattern(::Ifc4::IfcRecurrencePattern* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4::IfcWorkTime::Start() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4::IfcWorkTime::Finish() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcWorkTime::declaration() const { return *IFC4_IfcWorkTime_type; }
@@ -20444,9 +20444,9 @@ void Ifc4::IfcZShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWriteA
 double Ifc4::IfcZShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4::IfcZShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4::IfcZShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4::IfcZShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcZShapeProfileDef::declaration() const { return *IFC4_IfcZShapeProfileDef_type; }
@@ -20456,7 +20456,7 @@ Ifc4::IfcZShapeProfileDef::IfcZShapeProfileDef(::Ifc4::IfcProfileTypeEnum::Value
 
 // Function implementations for IfcZone
 boost::optional< std::string > Ifc4::IfcZone::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4::IfcZone::declaration() const { return *IFC4_IfcZone_type; }
diff --git a/src/ifcparse/Ifc4x1.cpp b/src/ifcparse/Ifc4x1.cpp
index e7814ae7bb..6799e2678f 100644
--- a/src/ifcparse/Ifc4x1.cpp
+++ b/src/ifcparse/Ifc4x1.cpp
@@ -11269,11 +11269,11 @@ Ifc4x1::IfcWarpingMomentMeasure::operator double() const { return *data_->getArg
 
 // Function implementations for IfcActionRequest
 boost::optional< ::Ifc4x1::IfcActionRequestTypeEnum::Value > Ifc4x1::IfcActionRequest::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x1::IfcActionRequestTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x1::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x1::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcActionRequestTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x1::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x1::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcActionRequestTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcActionRequest::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcActionRequest::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcActionRequest::declaration() const { return *IFC4X1_IfcActionRequest_type; }
@@ -11296,9 +11296,9 @@ Ifc4x1::IfcActor::IfcActor(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory* v
 ::Ifc4x1::IfcRoleEnum::Value Ifc4x1::IfcActorRole::Role() const {  return ::Ifc4x1::IfcRoleEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x1::IfcActorRole::setRole(::Ifc4x1::IfcRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcRoleEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcActorRole::UserDefinedRole() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcActorRole::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x1::IfcExternalReferenceRelationship::list::ptr Ifc4x1::IfcActorRole::HasExternalReference() const { return data_->getInverse(IFC4X1_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -11309,7 +11309,7 @@ Ifc4x1::IfcActorRole::IfcActorRole(::Ifc4x1::IfcRoleEnum::Value v1_Role, boost::
 
 // Function implementations for IfcActuator
 boost::optional< ::Ifc4x1::IfcActuatorTypeEnum::Value > Ifc4x1::IfcActuator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcActuatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x1::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcActuatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x1::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcActuatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcActuator::declaration() const { return *IFC4X1_IfcActuator_type; }
@@ -11329,11 +11329,11 @@ Ifc4x1::IfcActuatorType::IfcActuatorType(std::string v1_GlobalId, ::Ifc4x1::IfcO
 
 // Function implementations for IfcAddress
 boost::optional< ::Ifc4x1::IfcAddressTypeEnum::Value > Ifc4x1::IfcAddress::Purpose() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } return ::Ifc4x1::IfcAddressTypeEnum::FromString(*data_->getArgument(0)); }
-void Ifc4x1::IfcAddress::setPurpose(boost::optional< ::Ifc4x1::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAddressTypeEnum::ToString(*v)));data_->setArgument(0,attr);} }
+void Ifc4x1::IfcAddress::setPurpose(boost::optional< ::Ifc4x1::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAddressTypeEnum::ToString(*v)));}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAddress::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAddress::UserDefinedPurpose() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x1::IfcPerson::list::ptr Ifc4x1::IfcAddress::OfPerson() const { return data_->getInverse(IFC4X1_IfcPerson_type, 7)->as<IfcPerson>(); }
 ::Ifc4x1::IfcOrganization::list::ptr Ifc4x1::IfcAddress::OfOrganization() const { return data_->getInverse(IFC4X1_IfcOrganization_type, 4)->as<IfcOrganization>(); }
@@ -11371,7 +11371,7 @@ Ifc4x1::IfcAdvancedFace::IfcAdvancedFace(aggregate_of< ::Ifc4x1::IfcFaceBound >:
 
 // Function implementations for IfcAirTerminal
 boost::optional< ::Ifc4x1::IfcAirTerminalTypeEnum::Value > Ifc4x1::IfcAirTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcAirTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x1::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAirTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x1::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAirTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcAirTerminal::declaration() const { return *IFC4X1_IfcAirTerminal_type; }
@@ -11381,7 +11381,7 @@ Ifc4x1::IfcAirTerminal::IfcAirTerminal(std::string v1_GlobalId, ::Ifc4x1::IfcOwn
 
 // Function implementations for IfcAirTerminalBox
 boost::optional< ::Ifc4x1::IfcAirTerminalBoxTypeEnum::Value > Ifc4x1::IfcAirTerminalBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcAirTerminalBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x1::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAirTerminalBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x1::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAirTerminalBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcAirTerminalBox::declaration() const { return *IFC4X1_IfcAirTerminalBox_type; }
@@ -11411,7 +11411,7 @@ Ifc4x1::IfcAirTerminalType::IfcAirTerminalType(std::string v1_GlobalId, ::Ifc4x1
 
 // Function implementations for IfcAirToAirHeatRecovery
 boost::optional< ::Ifc4x1::IfcAirToAirHeatRecoveryTypeEnum::Value > Ifc4x1::IfcAirToAirHeatRecovery::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcAirToAirHeatRecoveryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x1::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x1::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcAirToAirHeatRecovery::declaration() const { return *IFC4X1_IfcAirToAirHeatRecovery_type; }
@@ -11431,7 +11431,7 @@ Ifc4x1::IfcAirToAirHeatRecoveryType::IfcAirToAirHeatRecoveryType(std::string v1_
 
 // Function implementations for IfcAlarm
 boost::optional< ::Ifc4x1::IfcAlarmTypeEnum::Value > Ifc4x1::IfcAlarm::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcAlarmTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x1::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAlarmTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x1::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAlarmTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcAlarm::declaration() const { return *IFC4X1_IfcAlarm_type; }
@@ -11451,7 +11451,7 @@ Ifc4x1::IfcAlarmType::IfcAlarmType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHi
 
 // Function implementations for IfcAlignment
 boost::optional< ::Ifc4x1::IfcAlignmentTypeEnum::Value > Ifc4x1::IfcAlignment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcAlignmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x1::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAlignmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x1::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAlignmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcAlignment::declaration() const { return *IFC4X1_IfcAlignment_type; }
@@ -11461,7 +11461,7 @@ Ifc4x1::IfcAlignment::IfcAlignment(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHi
 
 // Function implementations for IfcAlignment2DHorizontal
 boost::optional< double > Ifc4x1::IfcAlignment2DHorizontal::StartDistAlong() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcAlignment2DHorizontal::setStartDistAlong(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcAlignment2DHorizontal::setStartDistAlong(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc4x1::IfcAlignment2DHorizontalSegment >::ptr Ifc4x1::IfcAlignment2DHorizontal::Segments() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x1::IfcAlignment2DHorizontalSegment >(); }
 void Ifc4x1::IfcAlignment2DHorizontal::setSegments(aggregate_of< ::Ifc4x1::IfcAlignment2DHorizontalSegment >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -11485,11 +11485,11 @@ Ifc4x1::IfcAlignment2DHorizontalSegment::IfcAlignment2DHorizontalSegment(boost::
 
 // Function implementations for IfcAlignment2DSegment
 boost::optional< bool > Ifc4x1::IfcAlignment2DSegment::TangentialContinuity() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } bool v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcAlignment2DSegment::setTangentialContinuity(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcAlignment2DSegment::setTangentialContinuity(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAlignment2DSegment::StartTag() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcAlignment2DSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcAlignment2DSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAlignment2DSegment::EndTag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcAlignment2DSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcAlignment2DSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcAlignment2DSegment::declaration() const { return *IFC4X1_IfcAlignment2DSegment_type; }
@@ -11563,7 +11563,7 @@ void Ifc4x1::IfcAlignmentCurve::setHorizontal(::Ifc4x1::IfcAlignment2DHorizontal
 ::Ifc4x1::IfcAlignment2DVertical* Ifc4x1::IfcAlignmentCurve::Vertical() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x1::IfcAlignment2DVertical>(true); }
 void Ifc4x1::IfcAlignmentCurve::setVertical(::Ifc4x1::IfcAlignment2DVertical* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAlignmentCurve::Tag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcAlignmentCurve::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcAlignmentCurve::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcAlignmentCurve::declaration() const { return *IFC4X1_IfcAlignmentCurve_type; }
@@ -11584,7 +11584,7 @@ Ifc4x1::IfcAnnotation::IfcAnnotation(std::string v1_GlobalId, ::Ifc4x1::IfcOwner
 ::Ifc4x1::IfcCurve* Ifc4x1::IfcAnnotationFillArea::OuterBoundary() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x1::IfcCurve>(true); }
 void Ifc4x1::IfcAnnotationFillArea::setOuterBoundary(::Ifc4x1::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcCurve >::ptr > Ifc4x1::IfcAnnotationFillArea::InnerBoundaries() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x1::IfcCurve >(); }
-void Ifc4x1::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x1::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x1::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x1::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcAnnotationFillArea::declaration() const { return *IFC4X1_IfcAnnotationFillArea_type; }
@@ -11610,25 +11610,25 @@ Ifc4x1::IfcApplication::IfcApplication(::Ifc4x1::IfcOrganization* v1_Application
 
 // Function implementations for IfcAppliedValue
 boost::optional< std::string > Ifc4x1::IfcAppliedValue::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAppliedValue::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x1::IfcAppliedValueSelect* Ifc4x1::IfcAppliedValue::AppliedValue() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x1::IfcAppliedValueSelect>(true); }
 void Ifc4x1::IfcAppliedValue::setAppliedValue(::Ifc4x1::IfcAppliedValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcMeasureWithUnit* Ifc4x1::IfcAppliedValue::UnitBasis() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcMeasureWithUnit>(true); }
 void Ifc4x1::IfcAppliedValue::setUnitBasis(::Ifc4x1::IfcMeasureWithUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAppliedValue::ApplicableDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAppliedValue::FixedUntilDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAppliedValue::Category() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAppliedValue::Condition() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x1::IfcArithmeticOperatorEnum::Value > Ifc4x1::IfcAppliedValue::ArithmeticOperator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcArithmeticOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x1::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcArithmeticOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x1::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcArithmeticOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcAppliedValue >::ptr > Ifc4x1::IfcAppliedValue::Components() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x1::IfcAppliedValue >(); }
-void Ifc4x1::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x1::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 
 ::Ifc4x1::IfcExternalReferenceRelationship::list::ptr Ifc4x1::IfcAppliedValue::HasExternalReference() const { return data_->getInverse(IFC4X1_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -11639,19 +11639,19 @@ Ifc4x1::IfcAppliedValue::IfcAppliedValue(boost::optional< std::string > v1_Name,
 
 // Function implementations for IfcApproval
 boost::optional< std::string > Ifc4x1::IfcApproval::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcApproval::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcApproval::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x1::IfcApproval::TimeOfApproval() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcApproval::Status() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcApproval::Level() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcApproval::Qualifier() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x1::IfcActorSelect* Ifc4x1::IfcApproval::RequestingApproval() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x1::IfcActorSelect>(true); }
 void Ifc4x1::IfcApproval::setRequestingApproval(::Ifc4x1::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x1::IfcActorSelect* Ifc4x1::IfcApproval::GivingApproval() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x1::IfcActorSelect>(true); }
@@ -11712,7 +11712,7 @@ Ifc4x1::IfcArbitraryProfileDefWithVoids::IfcArbitraryProfileDefWithVoids(::Ifc4x
 
 // Function implementations for IfcAsset
 boost::optional< std::string > Ifc4x1::IfcAsset::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x1::IfcCostValue* Ifc4x1::IfcAsset::OriginalValue() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcCostValue>(true); }
 void Ifc4x1::IfcAsset::setOriginalValue(::Ifc4x1::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 ::Ifc4x1::IfcCostValue* Ifc4x1::IfcAsset::CurrentValue() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x1::IfcCostValue>(true); }
@@ -11726,7 +11726,7 @@ void Ifc4x1::IfcAsset::setUser(::Ifc4x1::IfcActorSelect* v) { {IfcWrite::IfcWrit
 ::Ifc4x1::IfcPerson* Ifc4x1::IfcAsset::ResponsiblePerson() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x1::IfcPerson>(true); }
 void Ifc4x1::IfcAsset::setResponsiblePerson(::Ifc4x1::IfcPerson* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x1::IfcAsset::IncorporationDate() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x1::IfcCostValue* Ifc4x1::IfcAsset::DepreciatedValue() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x1::IfcCostValue>(true); }
 void Ifc4x1::IfcAsset::setDepreciatedValue(::Ifc4x1::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -11746,21 +11746,21 @@ void Ifc4x1::IfcAsymmetricIShapeProfileDef::setWebThickness(double v) { {IfcWrit
 double Ifc4x1::IfcAsymmetricIShapeProfileDef::BottomFlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x1::IfcAsymmetricIShapeProfileDef::setBottomFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcAsymmetricIShapeProfileDef::BottomFlangeFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 double Ifc4x1::IfcAsymmetricIShapeProfileDef::TopFlangeWidth() const {  double v = *data_->getArgument(8); return v; }
 void Ifc4x1::IfcAsymmetricIShapeProfileDef::setTopFlangeWidth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x1::IfcAsymmetricIShapeProfileDef::TopFlangeThickness() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcAsymmetricIShapeProfileDef::TopFlangeFilletRadius() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcAsymmetricIShapeProfileDef::BottomFlangeEdgeRadius() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x1::IfcAsymmetricIShapeProfileDef::BottomFlangeSlope() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x1::IfcAsymmetricIShapeProfileDef::TopFlangeEdgeRadius() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x1::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x1::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x1::IfcAsymmetricIShapeProfileDef::TopFlangeSlope() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x1::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x1::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcAsymmetricIShapeProfileDef::declaration() const { return *IFC4X1_IfcAsymmetricIShapeProfileDef_type; }
@@ -11770,7 +11770,7 @@ Ifc4x1::IfcAsymmetricIShapeProfileDef::IfcAsymmetricIShapeProfileDef(::Ifc4x1::I
 
 // Function implementations for IfcAudioVisualAppliance
 boost::optional< ::Ifc4x1::IfcAudioVisualApplianceTypeEnum::Value > Ifc4x1::IfcAudioVisualAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcAudioVisualApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x1::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAudioVisualApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x1::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAudioVisualApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcAudioVisualAppliance::declaration() const { return *IFC4X1_IfcAudioVisualAppliance_type; }
@@ -11894,7 +11894,7 @@ Ifc4x1::IfcBSplineSurfaceWithKnots::IfcBSplineSurfaceWithKnots(int v1_UDegree, i
 
 // Function implementations for IfcBeam
 boost::optional< ::Ifc4x1::IfcBeamTypeEnum::Value > Ifc4x1::IfcBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x1::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x1::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcBeam::declaration() const { return *IFC4X1_IfcBeam_type; }
@@ -11948,7 +11948,7 @@ Ifc4x1::IfcBlock::IfcBlock(::Ifc4x1::IfcAxis2Placement3D* v1_Position, double v2
 
 // Function implementations for IfcBoiler
 boost::optional< ::Ifc4x1::IfcBoilerTypeEnum::Value > Ifc4x1::IfcBoiler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcBoilerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x1::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBoilerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x1::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBoilerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcBoiler::declaration() const { return *IFC4X1_IfcBoiler_type; }
@@ -11990,7 +11990,7 @@ Ifc4x1::IfcBooleanResult::IfcBooleanResult(::Ifc4x1::IfcBooleanOperator::Value v
 
 // Function implementations for IfcBoundaryCondition
 boost::optional< std::string > Ifc4x1::IfcBoundaryCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcBoundaryCondition::declaration() const { return *IFC4X1_IfcBoundaryCondition_type; }
@@ -12114,9 +12114,9 @@ Ifc4x1::IfcBoxedHalfSpace::IfcBoxedHalfSpace(::Ifc4x1::IfcSurface* v1_BaseSurfac
 
 // Function implementations for IfcBuilding
 boost::optional< double > Ifc4x1::IfcBuilding::ElevationOfRefHeight() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcBuilding::ElevationOfTerrain() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x1::IfcPostalAddress* Ifc4x1::IfcBuilding::BuildingAddress() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x1::IfcPostalAddress>(true); }
 void Ifc4x1::IfcBuilding::setBuildingAddress(::Ifc4x1::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 
@@ -12136,7 +12136,7 @@ Ifc4x1::IfcBuildingElement::IfcBuildingElement(std::string v1_GlobalId, ::Ifc4x1
 
 // Function implementations for IfcBuildingElementPart
 boost::optional< ::Ifc4x1::IfcBuildingElementPartTypeEnum::Value > Ifc4x1::IfcBuildingElementPart::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcBuildingElementPartTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x1::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBuildingElementPartTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x1::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBuildingElementPartTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcBuildingElementPart::declaration() const { return *IFC4X1_IfcBuildingElementPart_type; }
@@ -12156,7 +12156,7 @@ Ifc4x1::IfcBuildingElementPartType::IfcBuildingElementPartType(std::string v1_Gl
 
 // Function implementations for IfcBuildingElementProxy
 boost::optional< ::Ifc4x1::IfcBuildingElementProxyTypeEnum::Value > Ifc4x1::IfcBuildingElementProxy::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcBuildingElementProxyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x1::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBuildingElementProxyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x1::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBuildingElementProxyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcBuildingElementProxy::declaration() const { return *IFC4X1_IfcBuildingElementProxy_type; }
@@ -12184,7 +12184,7 @@ Ifc4x1::IfcBuildingElementType::IfcBuildingElementType(std::string v1_GlobalId,
 
 // Function implementations for IfcBuildingStorey
 boost::optional< double > Ifc4x1::IfcBuildingStorey::Elevation() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcBuildingStorey::declaration() const { return *IFC4X1_IfcBuildingStorey_type; }
@@ -12194,9 +12194,9 @@ Ifc4x1::IfcBuildingStorey::IfcBuildingStorey(std::string v1_GlobalId, ::Ifc4x1::
 
 // Function implementations for IfcBuildingSystem
 boost::optional< ::Ifc4x1::IfcBuildingSystemTypeEnum::Value > Ifc4x1::IfcBuildingSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x1::IfcBuildingSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x1::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x1::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBuildingSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x1::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x1::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBuildingSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcBuildingSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcBuildingSystem::declaration() const { return *IFC4X1_IfcBuildingSystem_type; }
@@ -12206,7 +12206,7 @@ Ifc4x1::IfcBuildingSystem::IfcBuildingSystem(std::string v1_GlobalId, ::Ifc4x1::
 
 // Function implementations for IfcBurner
 boost::optional< ::Ifc4x1::IfcBurnerTypeEnum::Value > Ifc4x1::IfcBurner::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcBurnerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x1::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBurnerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x1::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcBurnerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcBurner::declaration() const { return *IFC4X1_IfcBurner_type; }
@@ -12234,7 +12234,7 @@ void Ifc4x1::IfcCShapeProfileDef::setWallThickness(double v) { {IfcWrite::IfcWri
 double Ifc4x1::IfcCShapeProfileDef::Girth() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x1::IfcCShapeProfileDef::setGirth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcCShapeProfileDef::InternalFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCShapeProfileDef::declaration() const { return *IFC4X1_IfcCShapeProfileDef_type; }
@@ -12244,7 +12244,7 @@ Ifc4x1::IfcCShapeProfileDef::IfcCShapeProfileDef(::Ifc4x1::IfcProfileTypeEnum::V
 
 // Function implementations for IfcCableCarrierFitting
 boost::optional< ::Ifc4x1::IfcCableCarrierFittingTypeEnum::Value > Ifc4x1::IfcCableCarrierFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCableCarrierFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x1::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCableCarrierFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x1::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCableCarrierFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCableCarrierFitting::declaration() const { return *IFC4X1_IfcCableCarrierFitting_type; }
@@ -12264,7 +12264,7 @@ Ifc4x1::IfcCableCarrierFittingType::IfcCableCarrierFittingType(std::string v1_Gl
 
 // Function implementations for IfcCableCarrierSegment
 boost::optional< ::Ifc4x1::IfcCableCarrierSegmentTypeEnum::Value > Ifc4x1::IfcCableCarrierSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCableCarrierSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x1::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCableCarrierSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x1::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCableCarrierSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCableCarrierSegment::declaration() const { return *IFC4X1_IfcCableCarrierSegment_type; }
@@ -12284,7 +12284,7 @@ Ifc4x1::IfcCableCarrierSegmentType::IfcCableCarrierSegmentType(std::string v1_Gl
 
 // Function implementations for IfcCableFitting
 boost::optional< ::Ifc4x1::IfcCableFittingTypeEnum::Value > Ifc4x1::IfcCableFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCableFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x1::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCableFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x1::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCableFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCableFitting::declaration() const { return *IFC4X1_IfcCableFitting_type; }
@@ -12304,7 +12304,7 @@ Ifc4x1::IfcCableFittingType::IfcCableFittingType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCableSegment
 boost::optional< ::Ifc4x1::IfcCableSegmentTypeEnum::Value > Ifc4x1::IfcCableSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCableSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x1::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCableSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x1::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCableSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCableSegment::declaration() const { return *IFC4X1_IfcCableSegment_type; }
@@ -12344,7 +12344,7 @@ Ifc4x1::IfcCartesianPointList::IfcCartesianPointList() : IfcGeometricRepresentat
 std::vector< std::vector< double > > Ifc4x1::IfcCartesianPointList2D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcCartesianPointList2D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcCartesianPointList2D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCartesianPointList2D::declaration() const { return *IFC4X1_IfcCartesianPointList2D_type; }
@@ -12356,7 +12356,7 @@ Ifc4x1::IfcCartesianPointList2D::IfcCartesianPointList2D(std::vector< std::vecto
 std::vector< std::vector< double > > Ifc4x1::IfcCartesianPointList3D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcCartesianPointList3D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcCartesianPointList3D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCartesianPointList3D::declaration() const { return *IFC4X1_IfcCartesianPointList3D_type; }
@@ -12372,7 +12372,7 @@ void Ifc4x1::IfcCartesianTransformationOperator::setAxis2(::Ifc4x1::IfcDirection
 ::Ifc4x1::IfcCartesianPoint* Ifc4x1::IfcCartesianTransformationOperator::LocalOrigin() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x1::IfcCartesianPoint>(true); }
 void Ifc4x1::IfcCartesianTransformationOperator::setLocalOrigin(::Ifc4x1::IfcCartesianPoint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcCartesianTransformationOperator::Scale() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCartesianTransformationOperator::declaration() const { return *IFC4X1_IfcCartesianTransformationOperator_type; }
@@ -12390,7 +12390,7 @@ Ifc4x1::IfcCartesianTransformationOperator2D::IfcCartesianTransformationOperator
 
 // Function implementations for IfcCartesianTransformationOperator2DnonUniform
 boost::optional< double > Ifc4x1::IfcCartesianTransformationOperator2DnonUniform::Scale2() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCartesianTransformationOperator2DnonUniform::declaration() const { return *IFC4X1_IfcCartesianTransformationOperator2DnonUniform_type; }
@@ -12410,9 +12410,9 @@ Ifc4x1::IfcCartesianTransformationOperator3D::IfcCartesianTransformationOperator
 
 // Function implementations for IfcCartesianTransformationOperator3DnonUniform
 boost::optional< double > Ifc4x1::IfcCartesianTransformationOperator3DnonUniform::Scale2() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcCartesianTransformationOperator3DnonUniform::Scale3() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCartesianTransformationOperator3DnonUniform::declaration() const { return *IFC4X1_IfcCartesianTransformationOperator3DnonUniform_type; }
@@ -12432,7 +12432,7 @@ Ifc4x1::IfcCenterLineProfileDef::IfcCenterLineProfileDef(::Ifc4x1::IfcProfileTyp
 
 // Function implementations for IfcChiller
 boost::optional< ::Ifc4x1::IfcChillerTypeEnum::Value > Ifc4x1::IfcChiller::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcChillerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x1::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcChillerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x1::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcChillerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcChiller::declaration() const { return *IFC4X1_IfcChiller_type; }
@@ -12452,7 +12452,7 @@ Ifc4x1::IfcChillerType::IfcChillerType(std::string v1_GlobalId, ::Ifc4x1::IfcOwn
 
 // Function implementations for IfcChimney
 boost::optional< ::Ifc4x1::IfcChimneyTypeEnum::Value > Ifc4x1::IfcChimney::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcChimneyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x1::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcChimneyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x1::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcChimneyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcChimney::declaration() const { return *IFC4X1_IfcChimney_type; }
@@ -12530,19 +12530,19 @@ Ifc4x1::IfcCivilElementType::IfcCivilElementType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcClassification
 boost::optional< std::string > Ifc4x1::IfcClassification::Source() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcClassification::Edition() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcClassification::EditionDate() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::string Ifc4x1::IfcClassification::Name() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcClassification::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcClassification::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcClassification::Location() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcClassification::ReferenceTokens() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x1::IfcRelAssociatesClassification::list::ptr Ifc4x1::IfcClassification::ClassificationForObjects() const { return data_->getInverse(IFC4X1_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x1::IfcClassificationReference::list::ptr Ifc4x1::IfcClassification::HasReferences() const { return data_->getInverse(IFC4X1_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -12556,9 +12556,9 @@ Ifc4x1::IfcClassification::IfcClassification(boost::optional< std::string > v1_S
 ::Ifc4x1::IfcClassificationReferenceSelect* Ifc4x1::IfcClassificationReference::ReferencedSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcClassificationReferenceSelect>(true); }
 void Ifc4x1::IfcClassificationReference::setReferencedSource(::Ifc4x1::IfcClassificationReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcClassificationReference::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcClassificationReference::Sort() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x1::IfcRelAssociatesClassification::list::ptr Ifc4x1::IfcClassificationReference::ClassificationRefForObjects() const { return data_->getInverse(IFC4X1_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x1::IfcClassificationReference::list::ptr Ifc4x1::IfcClassificationReference::HasReferences() const { return data_->getInverse(IFC4X1_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -12578,7 +12578,7 @@ Ifc4x1::IfcClosedShell::IfcClosedShell(aggregate_of< ::Ifc4x1::IfcFace >::ptr v1
 
 // Function implementations for IfcCoil
 boost::optional< ::Ifc4x1::IfcCoilTypeEnum::Value > Ifc4x1::IfcCoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x1::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x1::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCoil::declaration() const { return *IFC4X1_IfcCoil_type; }
@@ -12622,7 +12622,7 @@ Ifc4x1::IfcColourRgbList::IfcColourRgbList(std::vector< std::vector< double > >
 
 // Function implementations for IfcColourSpecification
 boost::optional< std::string > Ifc4x1::IfcColourSpecification::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcColourSpecification::declaration() const { return *IFC4X1_IfcColourSpecification_type; }
@@ -12632,7 +12632,7 @@ Ifc4x1::IfcColourSpecification::IfcColourSpecification(boost::optional< std::str
 
 // Function implementations for IfcColumn
 boost::optional< ::Ifc4x1::IfcColumnTypeEnum::Value > Ifc4x1::IfcColumn::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcColumnTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x1::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcColumnTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x1::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcColumnTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcColumn::declaration() const { return *IFC4X1_IfcColumn_type; }
@@ -12660,7 +12660,7 @@ Ifc4x1::IfcColumnType::IfcColumnType(std::string v1_GlobalId, ::Ifc4x1::IfcOwner
 
 // Function implementations for IfcCommunicationsAppliance
 boost::optional< ::Ifc4x1::IfcCommunicationsApplianceTypeEnum::Value > Ifc4x1::IfcCommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x1::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x1::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCommunicationsAppliance::declaration() const { return *IFC4X1_IfcCommunicationsAppliance_type; }
@@ -12692,11 +12692,11 @@ Ifc4x1::IfcComplexProperty::IfcComplexProperty(std::string v1_Name, boost::optio
 
 // Function implementations for IfcComplexPropertyTemplate
 boost::optional< std::string > Ifc4x1::IfcComplexPropertyTemplate::UsageName() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x1::IfcComplexPropertyTemplateTypeEnum::Value > Ifc4x1::IfcComplexPropertyTemplate::TemplateType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x1::IfcComplexPropertyTemplateTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x1::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x1::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x1::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x1::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcPropertyTemplate >::ptr > Ifc4x1::IfcComplexPropertyTemplate::HasPropertyTemplates() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x1::IfcPropertyTemplate >(); }
-void Ifc4x1::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x1::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x1::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x1::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcComplexPropertyTemplate::declaration() const { return *IFC4X1_IfcComplexPropertyTemplate_type; }
@@ -12743,7 +12743,7 @@ Ifc4x1::IfcCompositeCurveSegment::IfcCompositeCurveSegment(::Ifc4x1::IfcTransiti
 aggregate_of< ::Ifc4x1::IfcProfileDef >::ptr Ifc4x1::IfcCompositeProfileDef::Profiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x1::IfcProfileDef >(); }
 void Ifc4x1::IfcCompositeProfileDef::setProfiles(aggregate_of< ::Ifc4x1::IfcProfileDef >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x1::IfcCompositeProfileDef::Label() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCompositeProfileDef::declaration() const { return *IFC4X1_IfcCompositeProfileDef_type; }
@@ -12753,7 +12753,7 @@ Ifc4x1::IfcCompositeProfileDef::IfcCompositeProfileDef(::Ifc4x1::IfcProfileTypeE
 
 // Function implementations for IfcCompressor
 boost::optional< ::Ifc4x1::IfcCompressorTypeEnum::Value > Ifc4x1::IfcCompressor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCompressorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x1::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCompressorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x1::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCompressorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCompressor::declaration() const { return *IFC4X1_IfcCompressor_type; }
@@ -12773,7 +12773,7 @@ Ifc4x1::IfcCompressorType::IfcCompressorType(std::string v1_GlobalId, ::Ifc4x1::
 
 // Function implementations for IfcCondenser
 boost::optional< ::Ifc4x1::IfcCondenserTypeEnum::Value > Ifc4x1::IfcCondenser::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCondenserTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x1::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCondenserTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x1::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCondenserTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCondenser::declaration() const { return *IFC4X1_IfcCondenser_type; }
@@ -12833,11 +12833,11 @@ Ifc4x1::IfcConnectionGeometry::IfcConnectionGeometry() : IfcUtil::IfcBaseEntity(
 
 // Function implementations for IfcConnectionPointEccentricity
 boost::optional< double > Ifc4x1::IfcConnectionPointEccentricity::EccentricityInX() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcConnectionPointEccentricity::EccentricityInY() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcConnectionPointEccentricity::EccentricityInZ() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcConnectionPointEccentricity::declaration() const { return *IFC4X1_IfcConnectionPointEccentricity_type; }
@@ -12885,17 +12885,17 @@ Ifc4x1::IfcConnectionVolumeGeometry::IfcConnectionVolumeGeometry(::Ifc4x1::IfcSo
 std::string Ifc4x1::IfcConstraint::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcConstraint::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcConstraint::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x1::IfcConstraintEnum::Value Ifc4x1::IfcConstraint::ConstraintGrade() const {  return ::Ifc4x1::IfcConstraintEnum::FromString(*data_->getArgument(2)); }
 void Ifc4x1::IfcConstraint::setConstraintGrade(::Ifc4x1::IfcConstraintEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcConstraintEnum::ToString(v)));data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x1::IfcConstraint::ConstraintSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x1::IfcActorSelect* Ifc4x1::IfcConstraint::CreatingActor() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x1::IfcActorSelect>(true); }
 void Ifc4x1::IfcConstraint::setCreatingActor(::Ifc4x1::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcConstraint::CreationTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcConstraint::UserDefinedGrade() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x1::IfcExternalReferenceRelationship::list::ptr Ifc4x1::IfcConstraint::HasExternalReferences() const { return data_->getInverse(IFC4X1_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x1::IfcResourceConstraintRelationship::list::ptr Ifc4x1::IfcConstraint::PropertiesForConstraint() const { return data_->getInverse(IFC4X1_IfcResourceConstraintRelationship_type, 2)->as<IfcResourceConstraintRelationship>(); }
@@ -12907,7 +12907,7 @@ Ifc4x1::IfcConstraint::IfcConstraint(std::string v1_Name, boost::optional< std::
 
 // Function implementations for IfcConstructionEquipmentResource
 boost::optional< ::Ifc4x1::IfcConstructionEquipmentResourceTypeEnum::Value > Ifc4x1::IfcConstructionEquipmentResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcConstructionEquipmentResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcConstructionEquipmentResource::declaration() const { return *IFC4X1_IfcConstructionEquipmentResource_type; }
@@ -12927,7 +12927,7 @@ Ifc4x1::IfcConstructionEquipmentResourceType::IfcConstructionEquipmentResourceTy
 
 // Function implementations for IfcConstructionMaterialResource
 boost::optional< ::Ifc4x1::IfcConstructionMaterialResourceTypeEnum::Value > Ifc4x1::IfcConstructionMaterialResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcConstructionMaterialResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcConstructionMaterialResource::declaration() const { return *IFC4X1_IfcConstructionMaterialResource_type; }
@@ -12947,7 +12947,7 @@ Ifc4x1::IfcConstructionMaterialResourceType::IfcConstructionMaterialResourceType
 
 // Function implementations for IfcConstructionProductResource
 boost::optional< ::Ifc4x1::IfcConstructionProductResourceTypeEnum::Value > Ifc4x1::IfcConstructionProductResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcConstructionProductResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcConstructionProductResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcConstructionProductResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcConstructionProductResource::declaration() const { return *IFC4X1_IfcConstructionProductResource_type; }
@@ -12969,7 +12969,7 @@ Ifc4x1::IfcConstructionProductResourceType::IfcConstructionProductResourceType(s
 ::Ifc4x1::IfcResourceTime* Ifc4x1::IfcConstructionResource::Usage() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x1::IfcResourceTime>(true); }
 void Ifc4x1::IfcConstructionResource::setUsage(::Ifc4x1::IfcResourceTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcAppliedValue >::ptr > Ifc4x1::IfcConstructionResource::BaseCosts() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x1::IfcAppliedValue >(); }
-void Ifc4x1::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x1::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x1::IfcPhysicalQuantity* Ifc4x1::IfcConstructionResource::BaseQuantity() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x1::IfcPhysicalQuantity>(true); }
 void Ifc4x1::IfcConstructionResource::setBaseQuantity(::Ifc4x1::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -12981,7 +12981,7 @@ Ifc4x1::IfcConstructionResource::IfcConstructionResource(std::string v1_GlobalId
 
 // Function implementations for IfcConstructionResourceType
 boost::optional< aggregate_of< ::Ifc4x1::IfcAppliedValue >::ptr > Ifc4x1::IfcConstructionResourceType::BaseCosts() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x1::IfcAppliedValue >(); }
-void Ifc4x1::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x1::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 ::Ifc4x1::IfcPhysicalQuantity* Ifc4x1::IfcConstructionResourceType::BaseQuantity() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x1::IfcPhysicalQuantity>(true); }
 void Ifc4x1::IfcConstructionResourceType::setBaseQuantity(::Ifc4x1::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -12993,13 +12993,13 @@ Ifc4x1::IfcConstructionResourceType::IfcConstructionResourceType(std::string v1_
 
 // Function implementations for IfcContext
 boost::optional< std::string > Ifc4x1::IfcContext::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcContext::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcContext::Phase() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcRepresentationContext >::ptr > Ifc4x1::IfcContext::RepresentationContexts() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x1::IfcRepresentationContext >(); }
-void Ifc4x1::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x1::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x1::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x1::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 ::Ifc4x1::IfcUnitAssignment* Ifc4x1::IfcContext::UnitsInContext() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x1::IfcUnitAssignment>(true); }
 void Ifc4x1::IfcContext::setUnitsInContext(::Ifc4x1::IfcUnitAssignment* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -13024,7 +13024,7 @@ Ifc4x1::IfcContextDependentUnit::IfcContextDependentUnit(::Ifc4x1::IfcDimensiona
 
 // Function implementations for IfcControl
 boost::optional< std::string > Ifc4x1::IfcControl::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x1::IfcRelAssignsToControl::list::ptr Ifc4x1::IfcControl::Controls() const { return data_->getInverse(IFC4X1_IfcRelAssignsToControl_type, 6)->as<IfcRelAssignsToControl>(); }
 
@@ -13035,7 +13035,7 @@ Ifc4x1::IfcControl::IfcControl(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistor
 
 // Function implementations for IfcController
 boost::optional< ::Ifc4x1::IfcControllerTypeEnum::Value > Ifc4x1::IfcController::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcControllerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcController::setPredefinedType(boost::optional< ::Ifc4x1::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcControllerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcController::setPredefinedType(boost::optional< ::Ifc4x1::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcControllerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcController::declaration() const { return *IFC4X1_IfcController_type; }
@@ -13078,7 +13078,7 @@ Ifc4x1::IfcConversionBasedUnitWithOffset::IfcConversionBasedUnitWithOffset(::Ifc
 
 // Function implementations for IfcCooledBeam
 boost::optional< ::Ifc4x1::IfcCooledBeamTypeEnum::Value > Ifc4x1::IfcCooledBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCooledBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x1::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCooledBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x1::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCooledBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCooledBeam::declaration() const { return *IFC4X1_IfcCooledBeam_type; }
@@ -13098,7 +13098,7 @@ Ifc4x1::IfcCooledBeamType::IfcCooledBeamType(std::string v1_GlobalId, ::Ifc4x1::
 
 // Function implementations for IfcCoolingTower
 boost::optional< ::Ifc4x1::IfcCoolingTowerTypeEnum::Value > Ifc4x1::IfcCoolingTower::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCoolingTowerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x1::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCoolingTowerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x1::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCoolingTowerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCoolingTower::declaration() const { return *IFC4X1_IfcCoolingTower_type; }
@@ -13132,11 +13132,11 @@ Ifc4x1::IfcCoordinateOperation::IfcCoordinateOperation(::Ifc4x1::IfcCoordinateRe
 std::string Ifc4x1::IfcCoordinateReferenceSystem::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcCoordinateReferenceSystem::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcCoordinateReferenceSystem::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcCoordinateReferenceSystem::GeodeticDatum() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x1::IfcCoordinateReferenceSystem::VerticalDatum() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 ::Ifc4x1::IfcCoordinateOperation::list::ptr Ifc4x1::IfcCoordinateReferenceSystem::HasCoordinateOperation() const { return data_->getInverse(IFC4X1_IfcCoordinateOperation_type, 0)->as<IfcCoordinateOperation>(); }
 
@@ -13147,11 +13147,11 @@ Ifc4x1::IfcCoordinateReferenceSystem::IfcCoordinateReferenceSystem(std::string v
 
 // Function implementations for IfcCostItem
 boost::optional< ::Ifc4x1::IfcCostItemTypeEnum::Value > Ifc4x1::IfcCostItem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCostItemTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x1::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x1::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCostItemTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x1::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x1::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCostItemTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcCostValue >::ptr > Ifc4x1::IfcCostItem::CostValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x1::IfcCostValue >(); }
-void Ifc4x1::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x1::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x1::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x1::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcPhysicalQuantity >::ptr > Ifc4x1::IfcCostItem::CostQuantities() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x1::IfcPhysicalQuantity >(); }
-void Ifc4x1::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x1::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x1::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCostItem::declaration() const { return *IFC4X1_IfcCostItem_type; }
@@ -13161,13 +13161,13 @@ Ifc4x1::IfcCostItem::IfcCostItem(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHist
 
 // Function implementations for IfcCostSchedule
 boost::optional< ::Ifc4x1::IfcCostScheduleTypeEnum::Value > Ifc4x1::IfcCostSchedule::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCostScheduleTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x1::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x1::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCostScheduleTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x1::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x1::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCostScheduleTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcCostSchedule::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcCostSchedule::SubmittedOn() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x1::IfcCostSchedule::UpdateDate() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCostSchedule::declaration() const { return *IFC4X1_IfcCostSchedule_type; }
@@ -13185,7 +13185,7 @@ Ifc4x1::IfcCostValue::IfcCostValue(boost::optional< std::string > v1_Name, boost
 
 // Function implementations for IfcCovering
 boost::optional< ::Ifc4x1::IfcCoveringTypeEnum::Value > Ifc4x1::IfcCovering::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCoveringTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x1::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCoveringTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x1::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCoveringTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x1::IfcRelCoversSpaces::list::ptr Ifc4x1::IfcCovering::CoversSpaces() const { return data_->getInverse(IFC4X1_IfcRelCoversSpaces_type, 5)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x1::IfcRelCoversBldgElements::list::ptr Ifc4x1::IfcCovering::CoversElements() const { return data_->getInverse(IFC4X1_IfcRelCoversBldgElements_type, 5)->as<IfcRelCoversBldgElements>(); }
@@ -13207,7 +13207,7 @@ Ifc4x1::IfcCoveringType::IfcCoveringType(std::string v1_GlobalId, ::Ifc4x1::IfcO
 
 // Function implementations for IfcCrewResource
 boost::optional< ::Ifc4x1::IfcCrewResourceTypeEnum::Value > Ifc4x1::IfcCrewResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCrewResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCrewResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCrewResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCrewResource::declaration() const { return *IFC4X1_IfcCrewResource_type; }
@@ -13253,7 +13253,7 @@ void Ifc4x1::IfcCurrencyRelationship::setRelatedMonetaryUnit(::Ifc4x1::IfcMoneta
 double Ifc4x1::IfcCurrencyRelationship::ExchangeRate() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x1::IfcCurrencyRelationship::setExchangeRate(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcCurrencyRelationship::RateDateTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x1::IfcLibraryInformation* Ifc4x1::IfcCurrencyRelationship::RateSource() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcLibraryInformation>(true); }
 void Ifc4x1::IfcCurrencyRelationship::setRateSource(::Ifc4x1::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -13265,7 +13265,7 @@ Ifc4x1::IfcCurrencyRelationship::IfcCurrencyRelationship(boost::optional< std::s
 
 // Function implementations for IfcCurtainWall
 boost::optional< ::Ifc4x1::IfcCurtainWallTypeEnum::Value > Ifc4x1::IfcCurtainWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCurtainWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x1::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCurtainWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x1::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCurtainWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCurtainWall::declaration() const { return *IFC4X1_IfcCurtainWall_type; }
@@ -13341,7 +13341,7 @@ void Ifc4x1::IfcCurveStyle::setCurveWidth(::Ifc4x1::IfcSizeSelect* v) { {IfcWrit
 ::Ifc4x1::IfcColour* Ifc4x1::IfcCurveStyle::CurveColour() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcColour>(true); }
 void Ifc4x1::IfcCurveStyle::setCurveColour(::Ifc4x1::IfcColour* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x1::IfcCurveStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcCurveStyle::declaration() const { return *IFC4X1_IfcCurveStyle_type; }
@@ -13351,7 +13351,7 @@ Ifc4x1::IfcCurveStyle::IfcCurveStyle(boost::optional< std::string > v1_Name, ::I
 
 // Function implementations for IfcCurveStyleFont
 boost::optional< std::string > Ifc4x1::IfcCurveStyleFont::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc4x1::IfcCurveStyleFontPattern >::ptr Ifc4x1::IfcCurveStyleFont::PatternList() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x1::IfcCurveStyleFontPattern >(); }
 void Ifc4x1::IfcCurveStyleFont::setPatternList(aggregate_of< ::Ifc4x1::IfcCurveStyleFontPattern >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -13363,7 +13363,7 @@ Ifc4x1::IfcCurveStyleFont::IfcCurveStyleFont(boost::optional< std::string > v1_N
 
 // Function implementations for IfcCurveStyleFontAndScaling
 boost::optional< std::string > Ifc4x1::IfcCurveStyleFontAndScaling::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x1::IfcCurveStyleFontSelect* Ifc4x1::IfcCurveStyleFontAndScaling::CurveFont() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x1::IfcCurveStyleFontSelect>(true); }
 void Ifc4x1::IfcCurveStyleFontAndScaling::setCurveFont(::Ifc4x1::IfcCurveStyleFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 double Ifc4x1::IfcCurveStyleFontAndScaling::CurveFontScaling() const {  double v = *data_->getArgument(2); return v; }
@@ -13399,7 +13399,7 @@ Ifc4x1::IfcCylindricalSurface::IfcCylindricalSurface(::Ifc4x1::IfcAxis2Placement
 
 // Function implementations for IfcDamper
 boost::optional< ::Ifc4x1::IfcDamperTypeEnum::Value > Ifc4x1::IfcDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x1::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x1::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDamper::declaration() const { return *IFC4X1_IfcDamper_type; }
@@ -13423,7 +13423,7 @@ void Ifc4x1::IfcDerivedProfileDef::setParentProfile(::Ifc4x1::IfcProfileDef* v)
 ::Ifc4x1::IfcCartesianTransformationOperator2D* Ifc4x1::IfcDerivedProfileDef::Operator() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x1::IfcDerivedProfileDef::setOperator(::Ifc4x1::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDerivedProfileDef::Label() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDerivedProfileDef::declaration() const { return *IFC4X1_IfcDerivedProfileDef_type; }
@@ -13437,7 +13437,7 @@ void Ifc4x1::IfcDerivedUnit::setElements(aggregate_of< ::Ifc4x1::IfcDerivedUnitE
 ::Ifc4x1::IfcDerivedUnitEnum::Value Ifc4x1::IfcDerivedUnit::UnitType() const {  return ::Ifc4x1::IfcDerivedUnitEnum::FromString(*data_->getArgument(1)); }
 void Ifc4x1::IfcDerivedUnit::setUnitType(::Ifc4x1::IfcDerivedUnitEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcDerivedUnitEnum::ToString(v)));data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDerivedUnit::UserDefinedType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDerivedUnit::declaration() const { return *IFC4X1_IfcDerivedUnit_type; }
@@ -13491,7 +13491,7 @@ Ifc4x1::IfcDirection::IfcDirection(std::vector< double > /*[2:3]*/ v1_DirectionR
 
 // Function implementations for IfcDiscreteAccessory
 boost::optional< ::Ifc4x1::IfcDiscreteAccessoryTypeEnum::Value > Ifc4x1::IfcDiscreteAccessory::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDiscreteAccessoryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x1::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDiscreteAccessoryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x1::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDiscreteAccessoryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDiscreteAccessory::declaration() const { return *IFC4X1_IfcDiscreteAccessory_type; }
@@ -13513,13 +13513,13 @@ Ifc4x1::IfcDiscreteAccessoryType::IfcDiscreteAccessoryType(std::string v1_Global
 double Ifc4x1::IfcDistanceExpression::DistanceAlong() const {  double v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcDistanceExpression::setDistanceAlong(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x1::IfcDistanceExpression::OffsetLateral() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcDistanceExpression::OffsetVertical() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcDistanceExpression::OffsetLongitudinal() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x1::IfcDistanceExpression::AlongHorizontal() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcDistanceExpression::setAlongHorizontal(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcDistanceExpression::setAlongHorizontal(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDistanceExpression::declaration() const { return *IFC4X1_IfcDistanceExpression_type; }
@@ -13529,7 +13529,7 @@ Ifc4x1::IfcDistanceExpression::IfcDistanceExpression(double v1_DistanceAlong, bo
 
 // Function implementations for IfcDistributionChamberElement
 boost::optional< ::Ifc4x1::IfcDistributionChamberElementTypeEnum::Value > Ifc4x1::IfcDistributionChamberElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDistributionChamberElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDistributionChamberElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDistributionChamberElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDistributionChamberElement::declaration() const { return *IFC4X1_IfcDistributionChamberElement_type; }
@@ -13608,11 +13608,11 @@ Ifc4x1::IfcDistributionFlowElementType::IfcDistributionFlowElementType(std::stri
 
 // Function implementations for IfcDistributionPort
 boost::optional< ::Ifc4x1::IfcFlowDirectionEnum::Value > Ifc4x1::IfcDistributionPort::FlowDirection() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x1::IfcFlowDirectionEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x1::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x1::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFlowDirectionEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x1::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x1::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFlowDirectionEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x1::IfcDistributionPortTypeEnum::Value > Ifc4x1::IfcDistributionPort::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDistributionPortTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x1::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDistributionPortTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x1::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDistributionPortTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x1::IfcDistributionSystemEnum::Value > Ifc4x1::IfcDistributionPort::SystemType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDistributionSystemEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x1::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x1::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x1::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x1::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDistributionPort::declaration() const { return *IFC4X1_IfcDistributionPort_type; }
@@ -13622,9 +13622,9 @@ Ifc4x1::IfcDistributionPort::IfcDistributionPort(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcDistributionSystem
 boost::optional< std::string > Ifc4x1::IfcDistributionSystem::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< ::Ifc4x1::IfcDistributionSystemEnum::Value > Ifc4x1::IfcDistributionSystem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDistributionSystemEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x1::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x1::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x1::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x1::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDistributionSystem::declaration() const { return *IFC4X1_IfcDistributionSystem_type; }
@@ -13638,35 +13638,35 @@ void Ifc4x1::IfcDocumentInformation::setIdentification(std::string v) { {IfcWrit
 std::string Ifc4x1::IfcDocumentInformation::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcDocumentInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::Location() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::Purpose() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::IntendedUse() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::Scope() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::Revision() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x1::IfcActorSelect* Ifc4x1::IfcDocumentInformation::DocumentOwner() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x1::IfcActorSelect>(true); }
 void Ifc4x1::IfcDocumentInformation::setDocumentOwner(::Ifc4x1::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x1::IfcDocumentInformation::Editors() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::CreationTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::LastRevisionTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::ElectronicFormat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::ValidFrom() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x1::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x1::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformation::ValidUntil() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x1::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x1::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< ::Ifc4x1::IfcDocumentConfidentialityEnum::Value > Ifc4x1::IfcDocumentInformation::Confidentiality() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDocumentConfidentialityEnum::FromString(*data_->getArgument(15)); }
-void Ifc4x1::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x1::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDocumentConfidentialityEnum::ToString(*v)));data_->setArgument(15,attr);} }
+void Ifc4x1::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x1::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDocumentConfidentialityEnum::ToString(*v)));}data_->setArgument(15,attr);} }
 boost::optional< ::Ifc4x1::IfcDocumentStatusEnum::Value > Ifc4x1::IfcDocumentInformation::Status() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDocumentStatusEnum::FromString(*data_->getArgument(16)); }
-void Ifc4x1::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x1::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDocumentStatusEnum::ToString(*v)));data_->setArgument(16,attr);} }
+void Ifc4x1::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x1::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDocumentStatusEnum::ToString(*v)));}data_->setArgument(16,attr);} }
 
 ::Ifc4x1::IfcRelAssociatesDocument::list::ptr Ifc4x1::IfcDocumentInformation::DocumentInfoForObjects() const { return data_->getInverse(IFC4X1_IfcRelAssociatesDocument_type, 5)->as<IfcRelAssociatesDocument>(); }
 ::Ifc4x1::IfcDocumentReference::list::ptr Ifc4x1::IfcDocumentInformation::HasDocumentReferences() const { return data_->getInverse(IFC4X1_IfcDocumentReference_type, 4)->as<IfcDocumentReference>(); }
@@ -13684,7 +13684,7 @@ void Ifc4x1::IfcDocumentInformationRelationship::setRelatingDocument(::Ifc4x1::I
 aggregate_of< ::Ifc4x1::IfcDocumentInformation >::ptr Ifc4x1::IfcDocumentInformationRelationship::RelatedDocuments() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x1::IfcDocumentInformation >(); }
 void Ifc4x1::IfcDocumentInformationRelationship::setRelatedDocuments(aggregate_of< ::Ifc4x1::IfcDocumentInformation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDocumentInformationRelationship::RelationshipType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDocumentInformationRelationship::declaration() const { return *IFC4X1_IfcDocumentInformationRelationship_type; }
@@ -13694,7 +13694,7 @@ Ifc4x1::IfcDocumentInformationRelationship::IfcDocumentInformationRelationship(b
 
 // Function implementations for IfcDocumentReference
 boost::optional< std::string > Ifc4x1::IfcDocumentReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x1::IfcDocumentInformation* Ifc4x1::IfcDocumentReference::ReferencedDocument() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x1::IfcDocumentInformation>(true); }
 void Ifc4x1::IfcDocumentReference::setReferencedDocument(::Ifc4x1::IfcDocumentInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -13707,15 +13707,15 @@ Ifc4x1::IfcDocumentReference::IfcDocumentReference(boost::optional< std::string
 
 // Function implementations for IfcDoor
 boost::optional< double > Ifc4x1::IfcDoor::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x1::IfcDoor::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x1::IfcDoorTypeEnum::Value > Ifc4x1::IfcDoor::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDoorTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x1::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDoorTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x1::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDoorTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x1::IfcDoorTypeOperationEnum::Value > Ifc4x1::IfcDoor::OperationType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x1::IfcDoor::setOperationType(boost::optional< ::Ifc4x1::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDoorTypeOperationEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x1::IfcDoor::setOperationType(boost::optional< ::Ifc4x1::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDoorTypeOperationEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDoor::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDoor::declaration() const { return *IFC4X1_IfcDoor_type; }
@@ -13725,31 +13725,31 @@ Ifc4x1::IfcDoor::IfcDoor(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory* v2_
 
 // Function implementations for IfcDoorLiningProperties
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::ThresholdDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::ThresholdThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::TransomThickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::TransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::LiningOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::ThresholdOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::CasingThickness() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::CasingDepth() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 ::Ifc4x1::IfcShapeAspect* Ifc4x1::IfcDoorLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(14)))->as<::Ifc4x1::IfcShapeAspect>(true); }
 void Ifc4x1::IfcDoorLiningProperties::setShapeAspectStyle(::Ifc4x1::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x1::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x1::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDoorLiningProperties::declaration() const { return *IFC4X1_IfcDoorLiningProperties_type; }
@@ -13759,11 +13759,11 @@ Ifc4x1::IfcDoorLiningProperties::IfcDoorLiningProperties(std::string v1_GlobalId
 
 // Function implementations for IfcDoorPanelProperties
 boost::optional< double > Ifc4x1::IfcDoorPanelProperties::PanelDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x1::IfcDoorPanelOperationEnum::Value Ifc4x1::IfcDoorPanelProperties::PanelOperation() const {  return ::Ifc4x1::IfcDoorPanelOperationEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x1::IfcDoorPanelProperties::setPanelOperation(::Ifc4x1::IfcDoorPanelOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcDoorPanelOperationEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcDoorPanelProperties::PanelWidth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x1::IfcDoorPanelPositionEnum::Value Ifc4x1::IfcDoorPanelProperties::PanelPosition() const {  return ::Ifc4x1::IfcDoorPanelPositionEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x1::IfcDoorPanelProperties::setPanelPosition(::Ifc4x1::IfcDoorPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcDoorPanelPositionEnum::ToString(v)));data_->setArgument(7,attr);} }
 ::Ifc4x1::IfcShapeAspect* Ifc4x1::IfcDoorPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x1::IfcShapeAspect>(true); }
@@ -13805,9 +13805,9 @@ void Ifc4x1::IfcDoorType::setPredefinedType(::Ifc4x1::IfcDoorTypeEnum::Value v)
 ::Ifc4x1::IfcDoorTypeOperationEnum::Value Ifc4x1::IfcDoorType::OperationType() const {  return ::Ifc4x1::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x1::IfcDoorType::setOperationType(::Ifc4x1::IfcDoorTypeOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcDoorTypeOperationEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x1::IfcDoorType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x1::IfcDoorType::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDoorType::declaration() const { return *IFC4X1_IfcDoorType_type; }
@@ -13833,7 +13833,7 @@ Ifc4x1::IfcDraughtingPreDefinedCurveFont::IfcDraughtingPreDefinedCurveFont(std::
 
 // Function implementations for IfcDuctFitting
 boost::optional< ::Ifc4x1::IfcDuctFittingTypeEnum::Value > Ifc4x1::IfcDuctFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDuctFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x1::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDuctFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x1::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDuctFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDuctFitting::declaration() const { return *IFC4X1_IfcDuctFitting_type; }
@@ -13853,7 +13853,7 @@ Ifc4x1::IfcDuctFittingType::IfcDuctFittingType(std::string v1_GlobalId, ::Ifc4x1
 
 // Function implementations for IfcDuctSegment
 boost::optional< ::Ifc4x1::IfcDuctSegmentTypeEnum::Value > Ifc4x1::IfcDuctSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDuctSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x1::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDuctSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x1::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDuctSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDuctSegment::declaration() const { return *IFC4X1_IfcDuctSegment_type; }
@@ -13873,7 +13873,7 @@ Ifc4x1::IfcDuctSegmentType::IfcDuctSegmentType(std::string v1_GlobalId, ::Ifc4x1
 
 // Function implementations for IfcDuctSilencer
 boost::optional< ::Ifc4x1::IfcDuctSilencerTypeEnum::Value > Ifc4x1::IfcDuctSilencer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDuctSilencerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x1::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDuctSilencerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x1::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDuctSilencerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcDuctSilencer::declaration() const { return *IFC4X1_IfcDuctSilencer_type; }
@@ -13927,7 +13927,7 @@ Ifc4x1::IfcEdgeLoop::IfcEdgeLoop(aggregate_of< ::Ifc4x1::IfcOrientedEdge >::ptr
 
 // Function implementations for IfcElectricAppliance
 boost::optional< ::Ifc4x1::IfcElectricApplianceTypeEnum::Value > Ifc4x1::IfcElectricAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcElectricApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcElectricAppliance::declaration() const { return *IFC4X1_IfcElectricAppliance_type; }
@@ -13947,7 +13947,7 @@ Ifc4x1::IfcElectricApplianceType::IfcElectricApplianceType(std::string v1_Global
 
 // Function implementations for IfcElectricDistributionBoard
 boost::optional< ::Ifc4x1::IfcElectricDistributionBoardTypeEnum::Value > Ifc4x1::IfcElectricDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcElectricDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcElectricDistributionBoard::declaration() const { return *IFC4X1_IfcElectricDistributionBoard_type; }
@@ -13967,7 +13967,7 @@ Ifc4x1::IfcElectricDistributionBoardType::IfcElectricDistributionBoardType(std::
 
 // Function implementations for IfcElectricFlowStorageDevice
 boost::optional< ::Ifc4x1::IfcElectricFlowStorageDeviceTypeEnum::Value > Ifc4x1::IfcElectricFlowStorageDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcElectricFlowStorageDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcElectricFlowStorageDevice::declaration() const { return *IFC4X1_IfcElectricFlowStorageDevice_type; }
@@ -13987,7 +13987,7 @@ Ifc4x1::IfcElectricFlowStorageDeviceType::IfcElectricFlowStorageDeviceType(std::
 
 // Function implementations for IfcElectricGenerator
 boost::optional< ::Ifc4x1::IfcElectricGeneratorTypeEnum::Value > Ifc4x1::IfcElectricGenerator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcElectricGeneratorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricGeneratorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricGeneratorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcElectricGenerator::declaration() const { return *IFC4X1_IfcElectricGenerator_type; }
@@ -14007,7 +14007,7 @@ Ifc4x1::IfcElectricGeneratorType::IfcElectricGeneratorType(std::string v1_Global
 
 // Function implementations for IfcElectricMotor
 boost::optional< ::Ifc4x1::IfcElectricMotorTypeEnum::Value > Ifc4x1::IfcElectricMotor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcElectricMotorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricMotorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricMotorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcElectricMotor::declaration() const { return *IFC4X1_IfcElectricMotor_type; }
@@ -14027,7 +14027,7 @@ Ifc4x1::IfcElectricMotorType::IfcElectricMotorType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcElectricTimeControl
 boost::optional< ::Ifc4x1::IfcElectricTimeControlTypeEnum::Value > Ifc4x1::IfcElectricTimeControl::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcElectricTimeControlTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricTimeControlTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x1::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElectricTimeControlTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcElectricTimeControl::declaration() const { return *IFC4X1_IfcElectricTimeControl_type; }
@@ -14047,7 +14047,7 @@ Ifc4x1::IfcElectricTimeControlType::IfcElectricTimeControlType(std::string v1_Gl
 
 // Function implementations for IfcElement
 boost::optional< std::string > Ifc4x1::IfcElement::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x1::IfcRelFillsElement::list::ptr Ifc4x1::IfcElement::FillsVoids() const { return data_->getInverse(IFC4X1_IfcRelFillsElement_type, 5)->as<IfcRelFillsElement>(); }
 ::Ifc4x1::IfcRelConnectsElements::list::ptr Ifc4x1::IfcElement::ConnectedTo() const { return data_->getInverse(IFC4X1_IfcRelConnectsElements_type, 5)->as<IfcRelConnectsElements>(); }
@@ -14069,9 +14069,9 @@ Ifc4x1::IfcElement::IfcElement(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistor
 
 // Function implementations for IfcElementAssembly
 boost::optional< ::Ifc4x1::IfcAssemblyPlaceEnum::Value > Ifc4x1::IfcElementAssembly::AssemblyPlace() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x1::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAssemblyPlaceEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x1::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcAssemblyPlaceEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x1::IfcElementAssemblyTypeEnum::Value > Ifc4x1::IfcElementAssembly::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x1::IfcElementAssemblyTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x1::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x1::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElementAssemblyTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x1::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x1::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElementAssemblyTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcElementAssembly::declaration() const { return *IFC4X1_IfcElementAssembly_type; }
@@ -14107,7 +14107,7 @@ Ifc4x1::IfcElementComponentType::IfcElementComponentType(std::string v1_GlobalId
 
 // Function implementations for IfcElementQuantity
 boost::optional< std::string > Ifc4x1::IfcElementQuantity::MethodOfMeasurement() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x1::IfcPhysicalQuantity >::ptr Ifc4x1::IfcElementQuantity::Quantities() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x1::IfcPhysicalQuantity >(); }
 void Ifc4x1::IfcElementQuantity::setQuantities(aggregate_of< ::Ifc4x1::IfcPhysicalQuantity >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -14119,7 +14119,7 @@ Ifc4x1::IfcElementQuantity::IfcElementQuantity(std::string v1_GlobalId, ::Ifc4x1
 
 // Function implementations for IfcElementType
 boost::optional< std::string > Ifc4x1::IfcElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcElementType::declaration() const { return *IFC4X1_IfcElementType_type; }
@@ -14179,7 +14179,7 @@ Ifc4x1::IfcEnergyConversionDeviceType::IfcEnergyConversionDeviceType(std::string
 
 // Function implementations for IfcEngine
 boost::optional< ::Ifc4x1::IfcEngineTypeEnum::Value > Ifc4x1::IfcEngine::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcEngineTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x1::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcEngineTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x1::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcEngineTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcEngine::declaration() const { return *IFC4X1_IfcEngine_type; }
@@ -14199,7 +14199,7 @@ Ifc4x1::IfcEngineType::IfcEngineType(std::string v1_GlobalId, ::Ifc4x1::IfcOwner
 
 // Function implementations for IfcEvaporativeCooler
 boost::optional< ::Ifc4x1::IfcEvaporativeCoolerTypeEnum::Value > Ifc4x1::IfcEvaporativeCooler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcEvaporativeCoolerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x1::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcEvaporativeCoolerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x1::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcEvaporativeCoolerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcEvaporativeCooler::declaration() const { return *IFC4X1_IfcEvaporativeCooler_type; }
@@ -14219,7 +14219,7 @@ Ifc4x1::IfcEvaporativeCoolerType::IfcEvaporativeCoolerType(std::string v1_Global
 
 // Function implementations for IfcEvaporator
 boost::optional< ::Ifc4x1::IfcEvaporatorTypeEnum::Value > Ifc4x1::IfcEvaporator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcEvaporatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x1::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcEvaporatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x1::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcEvaporatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcEvaporator::declaration() const { return *IFC4X1_IfcEvaporator_type; }
@@ -14239,11 +14239,11 @@ Ifc4x1::IfcEvaporatorType::IfcEvaporatorType(std::string v1_GlobalId, ::Ifc4x1::
 
 // Function implementations for IfcEvent
 boost::optional< ::Ifc4x1::IfcEventTypeEnum::Value > Ifc4x1::IfcEvent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x1::IfcEventTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x1::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x1::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcEventTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x1::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x1::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcEventTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x1::IfcEventTriggerTypeEnum::Value > Ifc4x1::IfcEvent::EventTriggerType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x1::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcEventTriggerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x1::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcEventTriggerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x1::IfcEvent::UserDefinedEventTriggerType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 ::Ifc4x1::IfcEventTime* Ifc4x1::IfcEvent::EventOccurenceTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x1::IfcEventTime>(true); }
 void Ifc4x1::IfcEvent::setEventOccurenceTime(::Ifc4x1::IfcEventTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -14255,13 +14255,13 @@ Ifc4x1::IfcEvent::IfcEvent(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory* v
 
 // Function implementations for IfcEventTime
 boost::optional< std::string > Ifc4x1::IfcEventTime::ActualDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcEventTime::EarlyDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcEventTime::LateDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcEventTime::ScheduleDate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcEventTime::declaration() const { return *IFC4X1_IfcEventTime_type; }
@@ -14275,7 +14275,7 @@ void Ifc4x1::IfcEventType::setPredefinedType(::Ifc4x1::IfcEventTypeEnum::Value v
 ::Ifc4x1::IfcEventTriggerTypeEnum::Value Ifc4x1::IfcEventType::EventTriggerType() const {  return ::Ifc4x1::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x1::IfcEventType::setEventTriggerType(::Ifc4x1::IfcEventTriggerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcEventTriggerTypeEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x1::IfcEventType::UserDefinedEventTriggerType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcEventType::declaration() const { return *IFC4X1_IfcEventType_type; }
@@ -14285,9 +14285,9 @@ Ifc4x1::IfcEventType::IfcEventType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHi
 
 // Function implementations for IfcExtendedProperties
 boost::optional< std::string > Ifc4x1::IfcExtendedProperties::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcExtendedProperties::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x1::IfcProperty >::ptr Ifc4x1::IfcExtendedProperties::Properties() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x1::IfcProperty >(); }
 void Ifc4x1::IfcExtendedProperties::setProperties(aggregate_of< ::Ifc4x1::IfcProperty >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -14307,11 +14307,11 @@ Ifc4x1::IfcExternalInformation::IfcExternalInformation() : IfcUtil::IfcBaseEntit
 
 // Function implementations for IfcExternalReference
 boost::optional< std::string > Ifc4x1::IfcExternalReference::Location() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcExternalReference::Identification() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcExternalReference::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x1::IfcExternalReferenceRelationship::list::ptr Ifc4x1::IfcExternalReference::ExternalReferenceForResources() const { return data_->getInverse(IFC4X1_IfcExternalReferenceRelationship_type, 2)->as<IfcExternalReferenceRelationship>(); }
 
@@ -14334,7 +14334,7 @@ Ifc4x1::IfcExternalReferenceRelationship::IfcExternalReferenceRelationship(boost
 
 // Function implementations for IfcExternalSpatialElement
 boost::optional< ::Ifc4x1::IfcExternalSpatialElementTypeEnum::Value > Ifc4x1::IfcExternalSpatialElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcExternalSpatialElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcExternalSpatialElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcExternalSpatialElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x1::IfcRelSpaceBoundary::list::ptr Ifc4x1::IfcExternalSpatialElement::BoundedBy() const { return data_->getInverse(IFC4X1_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
 
@@ -14470,17 +14470,17 @@ Ifc4x1::IfcFacetedBrepWithVoids::IfcFacetedBrepWithVoids(::Ifc4x1::IfcClosedShel
 
 // Function implementations for IfcFailureConnectionCondition
 boost::optional< double > Ifc4x1::IfcFailureConnectionCondition::TensionFailureX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcFailureConnectionCondition::TensionFailureY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcFailureConnectionCondition::TensionFailureZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcFailureConnectionCondition::CompressionFailureX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x1::IfcFailureConnectionCondition::CompressionFailureY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcFailureConnectionCondition::CompressionFailureZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFailureConnectionCondition::declaration() const { return *IFC4X1_IfcFailureConnectionCondition_type; }
@@ -14490,7 +14490,7 @@ Ifc4x1::IfcFailureConnectionCondition::IfcFailureConnectionCondition(boost::opti
 
 // Function implementations for IfcFan
 boost::optional< ::Ifc4x1::IfcFanTypeEnum::Value > Ifc4x1::IfcFan::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcFanTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcFan::setPredefinedType(boost::optional< ::Ifc4x1::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFanTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcFan::setPredefinedType(boost::optional< ::Ifc4x1::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFanTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFan::declaration() const { return *IFC4X1_IfcFan_type; }
@@ -14510,7 +14510,7 @@ Ifc4x1::IfcFanType::IfcFanType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistor
 
 // Function implementations for IfcFastener
 boost::optional< ::Ifc4x1::IfcFastenerTypeEnum::Value > Ifc4x1::IfcFastener::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcFastenerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x1::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFastenerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x1::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFastenerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFastener::declaration() const { return *IFC4X1_IfcFastener_type; }
@@ -14558,7 +14558,7 @@ Ifc4x1::IfcFeatureElementSubtraction::IfcFeatureElementSubtraction(std::string v
 aggregate_of_instance::ptr Ifc4x1::IfcFillAreaStyle::FillStyles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcFillAreaStyle::setFillStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x1::IfcFillAreaStyle::ModelorDraughting() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcFillAreaStyle::setModelorDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcFillAreaStyle::setModelorDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFillAreaStyle::declaration() const { return *IFC4X1_IfcFillAreaStyle_type; }
@@ -14600,7 +14600,7 @@ Ifc4x1::IfcFillAreaStyleTiles::IfcFillAreaStyleTiles(aggregate_of< ::Ifc4x1::Ifc
 
 // Function implementations for IfcFilter
 boost::optional< ::Ifc4x1::IfcFilterTypeEnum::Value > Ifc4x1::IfcFilter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcFilterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x1::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFilterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x1::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFilterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFilter::declaration() const { return *IFC4X1_IfcFilter_type; }
@@ -14620,7 +14620,7 @@ Ifc4x1::IfcFilterType::IfcFilterType(std::string v1_GlobalId, ::Ifc4x1::IfcOwner
 
 // Function implementations for IfcFireSuppressionTerminal
 boost::optional< ::Ifc4x1::IfcFireSuppressionTerminalTypeEnum::Value > Ifc4x1::IfcFireSuppressionTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcFireSuppressionTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x1::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x1::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFireSuppressionTerminal::declaration() const { return *IFC4X1_IfcFireSuppressionTerminal_type; }
@@ -14642,9 +14642,9 @@ Ifc4x1::IfcFireSuppressionTerminalType::IfcFireSuppressionTerminalType(std::stri
 ::Ifc4x1::IfcCurve* Ifc4x1::IfcFixedReferenceSweptAreaSolid::Directrix() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x1::IfcCurve>(true); }
 void Ifc4x1::IfcFixedReferenceSweptAreaSolid::setDirectrix(::Ifc4x1::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcFixedReferenceSweptAreaSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcFixedReferenceSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcFixedReferenceSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcFixedReferenceSweptAreaSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcFixedReferenceSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcFixedReferenceSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x1::IfcDirection* Ifc4x1::IfcFixedReferenceSweptAreaSolid::FixedReference() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x1::IfcDirection>(true); }
 void Ifc4x1::IfcFixedReferenceSweptAreaSolid::setFixedReference(::Ifc4x1::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -14688,7 +14688,7 @@ Ifc4x1::IfcFlowFittingType::IfcFlowFittingType(std::string v1_GlobalId, ::Ifc4x1
 
 // Function implementations for IfcFlowInstrument
 boost::optional< ::Ifc4x1::IfcFlowInstrumentTypeEnum::Value > Ifc4x1::IfcFlowInstrument::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcFlowInstrumentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x1::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFlowInstrumentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x1::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFlowInstrumentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFlowInstrument::declaration() const { return *IFC4X1_IfcFlowInstrument_type; }
@@ -14708,7 +14708,7 @@ Ifc4x1::IfcFlowInstrumentType::IfcFlowInstrumentType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcFlowMeter
 boost::optional< ::Ifc4x1::IfcFlowMeterTypeEnum::Value > Ifc4x1::IfcFlowMeter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcFlowMeterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x1::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFlowMeterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x1::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFlowMeterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFlowMeter::declaration() const { return *IFC4X1_IfcFlowMeter_type; }
@@ -14808,7 +14808,7 @@ Ifc4x1::IfcFlowTreatmentDeviceType::IfcFlowTreatmentDeviceType(std::string v1_Gl
 
 // Function implementations for IfcFooting
 boost::optional< ::Ifc4x1::IfcFootingTypeEnum::Value > Ifc4x1::IfcFooting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcFootingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x1::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFootingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x1::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFootingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFooting::declaration() const { return *IFC4X1_IfcFooting_type; }
@@ -14844,7 +14844,7 @@ Ifc4x1::IfcFurnishingElementType::IfcFurnishingElementType(std::string v1_Global
 
 // Function implementations for IfcFurniture
 boost::optional< ::Ifc4x1::IfcFurnitureTypeEnum::Value > Ifc4x1::IfcFurniture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcFurnitureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x1::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x1::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFurniture::declaration() const { return *IFC4X1_IfcFurniture_type; }
@@ -14856,7 +14856,7 @@ Ifc4x1::IfcFurniture::IfcFurniture(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHi
 ::Ifc4x1::IfcAssemblyPlaceEnum::Value Ifc4x1::IfcFurnitureType::AssemblyPlace() const {  return ::Ifc4x1::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x1::IfcFurnitureType::setAssemblyPlace(::Ifc4x1::IfcAssemblyPlaceEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcAssemblyPlaceEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x1::IfcFurnitureTypeEnum::Value > Ifc4x1::IfcFurnitureType::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcFurnitureTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x1::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x1::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcFurnitureType::declaration() const { return *IFC4X1_IfcFurnitureType_type; }
@@ -14866,7 +14866,7 @@ Ifc4x1::IfcFurnitureType::IfcFurnitureType(std::string v1_GlobalId, ::Ifc4x1::If
 
 // Function implementations for IfcGeographicElement
 boost::optional< ::Ifc4x1::IfcGeographicElementTypeEnum::Value > Ifc4x1::IfcGeographicElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcGeographicElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcGeographicElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcGeographicElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcGeographicElement::declaration() const { return *IFC4X1_IfcGeographicElement_type; }
@@ -14896,7 +14896,7 @@ Ifc4x1::IfcGeometricCurveSet::IfcGeometricCurveSet(aggregate_of_instance::ptr v1
 int Ifc4x1::IfcGeometricRepresentationContext::CoordinateSpaceDimension() const {  int v = *data_->getArgument(2); return v; }
 void Ifc4x1::IfcGeometricRepresentationContext::setCoordinateSpaceDimension(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcGeometricRepresentationContext::Precision() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x1::IfcAxis2Placement* Ifc4x1::IfcGeometricRepresentationContext::WorldCoordinateSystem() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x1::IfcAxis2Placement>(true); }
 void Ifc4x1::IfcGeometricRepresentationContext::setWorldCoordinateSystem(::Ifc4x1::IfcAxis2Placement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 ::Ifc4x1::IfcDirection* Ifc4x1::IfcGeometricRepresentationContext::TrueNorth() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x1::IfcDirection>(true); }
@@ -14922,11 +14922,11 @@ Ifc4x1::IfcGeometricRepresentationItem::IfcGeometricRepresentationItem() : IfcRe
 ::Ifc4x1::IfcGeometricRepresentationContext* Ifc4x1::IfcGeometricRepresentationSubContext::ParentContext() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcGeometricRepresentationContext>(true); }
 void Ifc4x1::IfcGeometricRepresentationSubContext::setParentContext(::Ifc4x1::IfcGeometricRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcGeometricRepresentationSubContext::TargetScale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x1::IfcGeometricProjectionEnum::Value Ifc4x1::IfcGeometricRepresentationSubContext::TargetView() const {  return ::Ifc4x1::IfcGeometricProjectionEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x1::IfcGeometricRepresentationSubContext::setTargetView(::Ifc4x1::IfcGeometricProjectionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcGeometricProjectionEnum::ToString(v)));data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x1::IfcGeometricRepresentationSubContext::UserDefinedTargetView() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcGeometricRepresentationSubContext::declaration() const { return *IFC4X1_IfcGeometricRepresentationSubContext_type; }
@@ -14950,9 +14950,9 @@ void Ifc4x1::IfcGrid::setUAxes(aggregate_of< ::Ifc4x1::IfcGridAxis >::ptr v) { {
 aggregate_of< ::Ifc4x1::IfcGridAxis >::ptr Ifc4x1::IfcGrid::VAxes() const {  aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x1::IfcGridAxis >(); }
 void Ifc4x1::IfcGrid::setVAxes(aggregate_of< ::Ifc4x1::IfcGridAxis >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcGridAxis >::ptr > Ifc4x1::IfcGrid::WAxes() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x1::IfcGridAxis >(); }
-void Ifc4x1::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x1::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x1::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x1::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x1::IfcGridTypeEnum::Value > Ifc4x1::IfcGrid::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcGridTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x1::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcGridTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x1::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcGridTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcGrid::declaration() const { return *IFC4X1_IfcGrid_type; }
@@ -14962,7 +14962,7 @@ Ifc4x1::IfcGrid::IfcGrid(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory* v2_
 
 // Function implementations for IfcGridAxis
 boost::optional< std::string > Ifc4x1::IfcGridAxis::AxisTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x1::IfcCurve* Ifc4x1::IfcGridAxis::AxisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x1::IfcCurve>(true); }
 void Ifc4x1::IfcGridAxis::setAxisCurve(::Ifc4x1::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 bool Ifc4x1::IfcGridAxis::SameSense() const {  bool v = *data_->getArgument(2); return v; }
@@ -15013,7 +15013,7 @@ Ifc4x1::IfcHalfSpaceSolid::IfcHalfSpaceSolid(::Ifc4x1::IfcSurface* v1_BaseSurfac
 
 // Function implementations for IfcHeatExchanger
 boost::optional< ::Ifc4x1::IfcHeatExchangerTypeEnum::Value > Ifc4x1::IfcHeatExchanger::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcHeatExchangerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x1::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcHeatExchangerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x1::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcHeatExchangerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcHeatExchanger::declaration() const { return *IFC4X1_IfcHeatExchanger_type; }
@@ -15033,7 +15033,7 @@ Ifc4x1::IfcHeatExchangerType::IfcHeatExchangerType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcHumidifier
 boost::optional< ::Ifc4x1::IfcHumidifierTypeEnum::Value > Ifc4x1::IfcHumidifier::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcHumidifierTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x1::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcHumidifierTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x1::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcHumidifierTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcHumidifier::declaration() const { return *IFC4X1_IfcHumidifier_type; }
@@ -15061,11 +15061,11 @@ void Ifc4x1::IfcIShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc4x1::IfcIShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x1::IfcIShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcIShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcIShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x1::IfcIShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcIShapeProfileDef::declaration() const { return *IFC4X1_IfcIShapeProfileDef_type; }
@@ -15087,7 +15087,7 @@ Ifc4x1::IfcImageTexture::IfcImageTexture(bool v1_RepeatS, bool v2_RepeatT, boost
 ::Ifc4x1::IfcTessellatedFaceSet* Ifc4x1::IfcIndexedColourMap::MappedTo() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x1::IfcTessellatedFaceSet>(true); }
 void Ifc4x1::IfcIndexedColourMap::setMappedTo(::Ifc4x1::IfcTessellatedFaceSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x1::IfcIndexedColourMap::Opacity() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x1::IfcColourRgbList* Ifc4x1::IfcIndexedColourMap::Colours() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x1::IfcColourRgbList>(true); }
 void Ifc4x1::IfcIndexedColourMap::setColours(::Ifc4x1::IfcColourRgbList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::vector< int > /*[1:?]*/ Ifc4x1::IfcIndexedColourMap::ColourIndex() const {  std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
@@ -15103,9 +15103,9 @@ Ifc4x1::IfcIndexedColourMap::IfcIndexedColourMap(::Ifc4x1::IfcTessellatedFaceSet
 ::Ifc4x1::IfcCartesianPointList* Ifc4x1::IfcIndexedPolyCurve::Points() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x1::IfcCartesianPointList>(true); }
 void Ifc4x1::IfcIndexedPolyCurve::setPoints(::Ifc4x1::IfcCartesianPointList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x1::IfcIndexedPolyCurve::Segments() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x1::IfcIndexedPolyCurve::SelfIntersect() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcIndexedPolyCurve::declaration() const { return *IFC4X1_IfcIndexedPolyCurve_type; }
@@ -15148,7 +15148,7 @@ Ifc4x1::IfcIndexedTextureMap::IfcIndexedTextureMap(aggregate_of< ::Ifc4x1::IfcSu
 
 // Function implementations for IfcIndexedTriangleTextureMap
 boost::optional< std::vector< std::vector< int > > > Ifc4x1::IfcIndexedTriangleTextureMap::TexCoordIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcIndexedTriangleTextureMap::declaration() const { return *IFC4X1_IfcIndexedTriangleTextureMap_type; }
@@ -15158,7 +15158,7 @@ Ifc4x1::IfcIndexedTriangleTextureMap::IfcIndexedTriangleTextureMap(aggregate_of<
 
 // Function implementations for IfcInterceptor
 boost::optional< ::Ifc4x1::IfcInterceptorTypeEnum::Value > Ifc4x1::IfcInterceptor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcInterceptorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x1::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcInterceptorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x1::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcInterceptorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcInterceptor::declaration() const { return *IFC4X1_IfcInterceptor_type; }
@@ -15186,13 +15186,13 @@ Ifc4x1::IfcIntersectionCurve::IfcIntersectionCurve(::Ifc4x1::IfcCurve* v1_Curve3
 
 // Function implementations for IfcInventory
 boost::optional< ::Ifc4x1::IfcInventoryTypeEnum::Value > Ifc4x1::IfcInventory::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x1::IfcInventoryTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x1::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x1::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcInventoryTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x1::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x1::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcInventoryTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 ::Ifc4x1::IfcActorSelect* Ifc4x1::IfcInventory::Jurisdiction() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcActorSelect>(true); }
 void Ifc4x1::IfcInventory::setJurisdiction(::Ifc4x1::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcPerson >::ptr > Ifc4x1::IfcInventory::ResponsiblePersons() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x1::IfcPerson >(); }
-void Ifc4x1::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x1::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x1::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x1::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcInventory::LastUpdateDate() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x1::IfcCostValue* Ifc4x1::IfcInventory::CurrentValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x1::IfcCostValue>(true); }
 void Ifc4x1::IfcInventory::setCurrentValue(::Ifc4x1::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x1::IfcCostValue* Ifc4x1::IfcInventory::OriginalValue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x1::IfcCostValue>(true); }
@@ -15228,7 +15228,7 @@ Ifc4x1::IfcIrregularTimeSeriesValue::IfcIrregularTimeSeriesValue(std::string v1_
 
 // Function implementations for IfcJunctionBox
 boost::optional< ::Ifc4x1::IfcJunctionBoxTypeEnum::Value > Ifc4x1::IfcJunctionBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcJunctionBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x1::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcJunctionBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x1::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcJunctionBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcJunctionBox::declaration() const { return *IFC4X1_IfcJunctionBox_type; }
@@ -15250,15 +15250,15 @@ Ifc4x1::IfcJunctionBoxType::IfcJunctionBoxType(std::string v1_GlobalId, ::Ifc4x1
 double Ifc4x1::IfcLShapeProfileDef::Depth() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcLShapeProfileDef::setDepth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcLShapeProfileDef::Width() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 double Ifc4x1::IfcLShapeProfileDef::Thickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x1::IfcLShapeProfileDef::setThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcLShapeProfileDef::FilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcLShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcLShapeProfileDef::LegSlope() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcLShapeProfileDef::declaration() const { return *IFC4X1_IfcLShapeProfileDef_type; }
@@ -15268,7 +15268,7 @@ Ifc4x1::IfcLShapeProfileDef::IfcLShapeProfileDef(::Ifc4x1::IfcProfileTypeEnum::V
 
 // Function implementations for IfcLaborResource
 boost::optional< ::Ifc4x1::IfcLaborResourceTypeEnum::Value > Ifc4x1::IfcLaborResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcLaborResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcLaborResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcLaborResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcLaborResource::declaration() const { return *IFC4X1_IfcLaborResource_type; }
@@ -15300,7 +15300,7 @@ Ifc4x1::IfcLagTime::IfcLagTime(boost::optional< std::string > v1_Name, boost::op
 
 // Function implementations for IfcLamp
 boost::optional< ::Ifc4x1::IfcLampTypeEnum::Value > Ifc4x1::IfcLamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcLampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x1::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcLampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x1::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcLampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcLamp::declaration() const { return *IFC4X1_IfcLamp_type; }
@@ -15322,15 +15322,15 @@ Ifc4x1::IfcLampType::IfcLampType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHist
 std::string Ifc4x1::IfcLibraryInformation::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcLibraryInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcLibraryInformation::Version() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x1::IfcActorSelect* Ifc4x1::IfcLibraryInformation::Publisher() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x1::IfcActorSelect>(true); }
 void Ifc4x1::IfcLibraryInformation::setPublisher(::Ifc4x1::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x1::IfcLibraryInformation::VersionDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcLibraryInformation::Location() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcLibraryInformation::Description() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x1::IfcRelAssociatesLibrary::list::ptr Ifc4x1::IfcLibraryInformation::LibraryInfoForObjects() const { return data_->getInverse(IFC4X1_IfcRelAssociatesLibrary_type, 5)->as<IfcRelAssociatesLibrary>(); }
 ::Ifc4x1::IfcLibraryReference::list::ptr Ifc4x1::IfcLibraryInformation::HasLibraryReferences() const { return data_->getInverse(IFC4X1_IfcLibraryReference_type, 5)->as<IfcLibraryReference>(); }
@@ -15342,9 +15342,9 @@ Ifc4x1::IfcLibraryInformation::IfcLibraryInformation(std::string v1_Name, boost:
 
 // Function implementations for IfcLibraryReference
 boost::optional< std::string > Ifc4x1::IfcLibraryReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcLibraryReference::Language() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x1::IfcLibraryInformation* Ifc4x1::IfcLibraryReference::ReferencedLibrary() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x1::IfcLibraryInformation>(true); }
 void Ifc4x1::IfcLibraryReference::setReferencedLibrary(::Ifc4x1::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -15371,7 +15371,7 @@ Ifc4x1::IfcLightDistributionData::IfcLightDistributionData(double v1_MainPlaneAn
 
 // Function implementations for IfcLightFixture
 boost::optional< ::Ifc4x1::IfcLightFixtureTypeEnum::Value > Ifc4x1::IfcLightFixture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcLightFixtureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x1::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcLightFixtureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x1::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcLightFixtureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcLightFixture::declaration() const { return *IFC4X1_IfcLightFixture_type; }
@@ -15403,13 +15403,13 @@ Ifc4x1::IfcLightIntensityDistribution::IfcLightIntensityDistribution(::Ifc4x1::I
 
 // Function implementations for IfcLightSource
 boost::optional< std::string > Ifc4x1::IfcLightSource::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x1::IfcColourRgb* Ifc4x1::IfcLightSource::LightColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x1::IfcColourRgb>(true); }
 void Ifc4x1::IfcLightSource::setLightColour(::Ifc4x1::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcLightSource::AmbientIntensity() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcLightSource::Intensity() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcLightSource::declaration() const { return *IFC4X1_IfcLightSource_type; }
@@ -15477,7 +15477,7 @@ Ifc4x1::IfcLightSourcePositional::IfcLightSourcePositional(boost::optional< std:
 ::Ifc4x1::IfcDirection* Ifc4x1::IfcLightSourceSpot::Orientation() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x1::IfcDirection>(true); }
 void Ifc4x1::IfcLightSourceSpot::setOrientation(::Ifc4x1::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcLightSourceSpot::ConcentrationExponent() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 double Ifc4x1::IfcLightSourceSpot::SpreadAngle() const {  double v = *data_->getArgument(11); return v; }
 void Ifc4x1::IfcLightSourceSpot::setSpreadAngle(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 double Ifc4x1::IfcLightSourceSpot::BeamWidthAngle() const {  double v = *data_->getArgument(12); return v; }
@@ -15573,11 +15573,11 @@ void Ifc4x1::IfcMapConversion::setNorthings(double v) { {IfcWrite::IfcWriteArgum
 double Ifc4x1::IfcMapConversion::OrthogonalHeight() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x1::IfcMapConversion::setOrthogonalHeight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x1::IfcMapConversion::XAxisAbscissa() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcMapConversion::XAxisOrdinate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcMapConversion::Scale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMapConversion::declaration() const { return *IFC4X1_IfcMapConversion_type; }
@@ -15601,9 +15601,9 @@ Ifc4x1::IfcMappedItem::IfcMappedItem(::Ifc4x1::IfcRepresentationMap* v1_MappingS
 std::string Ifc4x1::IfcMaterial::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcMaterial::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterial::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterial::Category() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x1::IfcMaterialDefinitionRepresentation::list::ptr Ifc4x1::IfcMaterial::HasRepresentation() const { return data_->getInverse(IFC4X1_IfcMaterialDefinitionRepresentation_type, 3)->as<IfcMaterialDefinitionRepresentation>(); }
 ::Ifc4x1::IfcMaterialRelationship::list::ptr Ifc4x1::IfcMaterial::IsRelatedWith() const { return data_->getInverse(IFC4X1_IfcMaterialRelationship_type, 3)->as<IfcMaterialRelationship>(); }
@@ -15628,15 +15628,15 @@ Ifc4x1::IfcMaterialClassificationRelationship::IfcMaterialClassificationRelation
 
 // Function implementations for IfcMaterialConstituent
 boost::optional< std::string > Ifc4x1::IfcMaterialConstituent::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialConstituent::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x1::IfcMaterial* Ifc4x1::IfcMaterialConstituent::Material() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x1::IfcMaterial>(true); }
 void Ifc4x1::IfcMaterialConstituent::setMaterial(::Ifc4x1::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcMaterialConstituent::Fraction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialConstituent::Category() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x1::IfcMaterialConstituentSet::list::ptr Ifc4x1::IfcMaterialConstituent::ToMaterialConstituentSet() const { return data_->getInverse(IFC4X1_IfcMaterialConstituentSet_type, 2)->as<IfcMaterialConstituentSet>(); }
 
@@ -15647,11 +15647,11 @@ Ifc4x1::IfcMaterialConstituent::IfcMaterialConstituent(boost::optional< std::str
 
 // Function implementations for IfcMaterialConstituentSet
 boost::optional< std::string > Ifc4x1::IfcMaterialConstituentSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialConstituentSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcMaterialConstituent >::ptr > Ifc4x1::IfcMaterialConstituentSet::MaterialConstituents() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x1::IfcMaterialConstituent >(); }
-void Ifc4x1::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x1::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x1::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x1::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMaterialConstituentSet::declaration() const { return *IFC4X1_IfcMaterialConstituentSet_type; }
@@ -15686,15 +15686,15 @@ void Ifc4x1::IfcMaterialLayer::setMaterial(::Ifc4x1::IfcMaterial* v) { {IfcWrite
 double Ifc4x1::IfcMaterialLayer::LayerThickness() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcMaterialLayer::setLayerThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< boost::logic::tribool > Ifc4x1::IfcMaterialLayer::IsVentilated() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } boost::logic::tribool v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialLayer::Name() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialLayer::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialLayer::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x1::IfcMaterialLayer::Priority() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x1::IfcMaterialLayerSet::list::ptr Ifc4x1::IfcMaterialLayer::ToMaterialLayerSet() const { return data_->getInverse(IFC4X1_IfcMaterialLayerSet_type, 0)->as<IfcMaterialLayerSet>(); }
 
@@ -15707,9 +15707,9 @@ Ifc4x1::IfcMaterialLayer::IfcMaterialLayer(::Ifc4x1::IfcMaterial* v1_Material, d
 aggregate_of< ::Ifc4x1::IfcMaterialLayer >::ptr Ifc4x1::IfcMaterialLayerSet::MaterialLayers() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x1::IfcMaterialLayer >(); }
 void Ifc4x1::IfcMaterialLayerSet::setMaterialLayers(aggregate_of< ::Ifc4x1::IfcMaterialLayer >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialLayerSet::LayerSetName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialLayerSet::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMaterialLayerSet::declaration() const { return *IFC4X1_IfcMaterialLayerSet_type; }
@@ -15727,7 +15727,7 @@ void Ifc4x1::IfcMaterialLayerSetUsage::setDirectionSense(::Ifc4x1::IfcDirectionS
 double Ifc4x1::IfcMaterialLayerSetUsage::OffsetFromReferenceLine() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcMaterialLayerSetUsage::setOffsetFromReferenceLine(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcMaterialLayerSetUsage::ReferenceExtent() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMaterialLayerSetUsage::declaration() const { return *IFC4X1_IfcMaterialLayerSetUsage_type; }
@@ -15759,17 +15759,17 @@ Ifc4x1::IfcMaterialList::IfcMaterialList(aggregate_of< ::Ifc4x1::IfcMaterial >::
 
 // Function implementations for IfcMaterialProfile
 boost::optional< std::string > Ifc4x1::IfcMaterialProfile::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialProfile::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x1::IfcMaterial* Ifc4x1::IfcMaterialProfile::Material() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x1::IfcMaterial>(true); }
 void Ifc4x1::IfcMaterialProfile::setMaterial(::Ifc4x1::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcProfileDef* Ifc4x1::IfcMaterialProfile::Profile() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcProfileDef>(true); }
 void Ifc4x1::IfcMaterialProfile::setProfile(::Ifc4x1::IfcProfileDef* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x1::IfcMaterialProfile::Priority() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialProfile::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x1::IfcMaterialProfileSet::list::ptr Ifc4x1::IfcMaterialProfile::ToMaterialProfileSet() const { return data_->getInverse(IFC4X1_IfcMaterialProfileSet_type, 2)->as<IfcMaterialProfileSet>(); }
 
@@ -15780,9 +15780,9 @@ Ifc4x1::IfcMaterialProfile::IfcMaterialProfile(boost::optional< std::string > v1
 
 // Function implementations for IfcMaterialProfileSet
 boost::optional< std::string > Ifc4x1::IfcMaterialProfileSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialProfileSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x1::IfcMaterialProfile >::ptr Ifc4x1::IfcMaterialProfileSet::MaterialProfiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x1::IfcMaterialProfile >(); }
 void Ifc4x1::IfcMaterialProfileSet::setMaterialProfiles(aggregate_of< ::Ifc4x1::IfcMaterialProfile >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcCompositeProfileDef* Ifc4x1::IfcMaterialProfileSet::CompositeProfile() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcCompositeProfileDef>(true); }
@@ -15798,9 +15798,9 @@ Ifc4x1::IfcMaterialProfileSet::IfcMaterialProfileSet(boost::optional< std::strin
 ::Ifc4x1::IfcMaterialProfileSet* Ifc4x1::IfcMaterialProfileSetUsage::ForProfileSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x1::IfcMaterialProfileSet>(true); }
 void Ifc4x1::IfcMaterialProfileSetUsage::setForProfileSet(::Ifc4x1::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< int > Ifc4x1::IfcMaterialProfileSetUsage::CardinalPoint() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } int v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcMaterialProfileSetUsage::ReferenceExtent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMaterialProfileSetUsage::declaration() const { return *IFC4X1_IfcMaterialProfileSetUsage_type; }
@@ -15812,7 +15812,7 @@ Ifc4x1::IfcMaterialProfileSetUsage::IfcMaterialProfileSetUsage(::Ifc4x1::IfcMate
 ::Ifc4x1::IfcMaterialProfileSet* Ifc4x1::IfcMaterialProfileSetUsageTapering::ForProfileEndSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcMaterialProfileSet>(true); }
 void Ifc4x1::IfcMaterialProfileSetUsageTapering::setForProfileEndSet(::Ifc4x1::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x1::IfcMaterialProfileSetUsageTapering::CardinalEndPoint() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMaterialProfileSetUsageTapering::declaration() const { return *IFC4X1_IfcMaterialProfileSetUsageTapering_type; }
@@ -15846,7 +15846,7 @@ void Ifc4x1::IfcMaterialRelationship::setRelatingMaterial(::Ifc4x1::IfcMaterial*
 aggregate_of< ::Ifc4x1::IfcMaterial >::ptr Ifc4x1::IfcMaterialRelationship::RelatedMaterials() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x1::IfcMaterial >(); }
 void Ifc4x1::IfcMaterialRelationship::setRelatedMaterials(aggregate_of< ::Ifc4x1::IfcMaterial >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMaterialRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMaterialRelationship::declaration() const { return *IFC4X1_IfcMaterialRelationship_type; }
@@ -15877,11 +15877,11 @@ Ifc4x1::IfcMeasureWithUnit::IfcMeasureWithUnit(::Ifc4x1::IfcValue* v1_ValueCompo
 
 // Function implementations for IfcMechanicalFastener
 boost::optional< double > Ifc4x1::IfcMechanicalFastener::NominalDiameter() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x1::IfcMechanicalFastener::NominalLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x1::IfcMechanicalFastenerTypeEnum::Value > Ifc4x1::IfcMechanicalFastener::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x1::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcMechanicalFastenerTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x1::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcMechanicalFastenerTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMechanicalFastener::declaration() const { return *IFC4X1_IfcMechanicalFastener_type; }
@@ -15893,9 +15893,9 @@ Ifc4x1::IfcMechanicalFastener::IfcMechanicalFastener(std::string v1_GlobalId, ::
 ::Ifc4x1::IfcMechanicalFastenerTypeEnum::Value Ifc4x1::IfcMechanicalFastenerType::PredefinedType() const {  return ::Ifc4x1::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x1::IfcMechanicalFastenerType::setPredefinedType(::Ifc4x1::IfcMechanicalFastenerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcMechanicalFastenerTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcMechanicalFastenerType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcMechanicalFastenerType::NominalLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMechanicalFastenerType::declaration() const { return *IFC4X1_IfcMechanicalFastenerType_type; }
@@ -15905,7 +15905,7 @@ Ifc4x1::IfcMechanicalFastenerType::IfcMechanicalFastenerType(std::string v1_Glob
 
 // Function implementations for IfcMedicalDevice
 boost::optional< ::Ifc4x1::IfcMedicalDeviceTypeEnum::Value > Ifc4x1::IfcMedicalDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcMedicalDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcMedicalDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcMedicalDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMedicalDevice::declaration() const { return *IFC4X1_IfcMedicalDevice_type; }
@@ -15925,7 +15925,7 @@ Ifc4x1::IfcMedicalDeviceType::IfcMedicalDeviceType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcMember
 boost::optional< ::Ifc4x1::IfcMemberTypeEnum::Value > Ifc4x1::IfcMember::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcMemberTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcMember::setPredefinedType(boost::optional< ::Ifc4x1::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcMemberTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcMember::setPredefinedType(boost::optional< ::Ifc4x1::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcMemberTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMember::declaration() const { return *IFC4X1_IfcMember_type; }
@@ -15955,7 +15955,7 @@ Ifc4x1::IfcMemberType::IfcMemberType(std::string v1_GlobalId, ::Ifc4x1::IfcOwner
 ::Ifc4x1::IfcBenchmarkEnum::Value Ifc4x1::IfcMetric::Benchmark() const {  return ::Ifc4x1::IfcBenchmarkEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x1::IfcMetric::setBenchmark(::Ifc4x1::IfcBenchmarkEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcBenchmarkEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcMetric::ValueSource() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x1::IfcMetricValueSelect* Ifc4x1::IfcMetric::DataValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x1::IfcMetricValueSelect>(true); }
 void Ifc4x1::IfcMetric::setDataValue(::Ifc4x1::IfcMetricValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x1::IfcReference* Ifc4x1::IfcMetric::ReferencePath() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x1::IfcReference>(true); }
@@ -15987,7 +15987,7 @@ Ifc4x1::IfcMonetaryUnit::IfcMonetaryUnit(std::string v1_Currency) : IfcUtil::Ifc
 
 // Function implementations for IfcMotorConnection
 boost::optional< ::Ifc4x1::IfcMotorConnectionTypeEnum::Value > Ifc4x1::IfcMotorConnection::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcMotorConnectionTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x1::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcMotorConnectionTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x1::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcMotorConnectionTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcMotorConnection::declaration() const { return *IFC4X1_IfcMotorConnection_type; }
@@ -16019,7 +16019,7 @@ Ifc4x1::IfcNamedUnit::IfcNamedUnit(::Ifc4x1::IfcDimensionalExponents* v1_Dimensi
 
 // Function implementations for IfcObject
 boost::optional< std::string > Ifc4x1::IfcObject::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x1::IfcRelDefinesByObject::list::ptr Ifc4x1::IfcObject::IsDeclaredBy() const { return data_->getInverse(IFC4X1_IfcRelDefinesByObject_type, 4)->as<IfcRelDefinesByObject>(); }
 ::Ifc4x1::IfcRelDefinesByObject::list::ptr Ifc4x1::IfcObject::Declares() const { return data_->getInverse(IFC4X1_IfcRelDefinesByObject_type, 5)->as<IfcRelDefinesByObject>(); }
@@ -16058,13 +16058,13 @@ Ifc4x1::IfcObjectPlacement::IfcObjectPlacement() : IfcUtil::IfcBaseEntity() {dat
 
 // Function implementations for IfcObjective
 boost::optional< aggregate_of< ::Ifc4x1::IfcConstraint >::ptr > Ifc4x1::IfcObjective::BenchmarkValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x1::IfcConstraint >(); }
-void Ifc4x1::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x1::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x1::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x1::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x1::IfcLogicalOperatorEnum::Value > Ifc4x1::IfcObjective::LogicalAggregator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcLogicalOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x1::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcLogicalOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x1::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcLogicalOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 ::Ifc4x1::IfcObjectiveEnum::Value Ifc4x1::IfcObjective::ObjectiveQualifier() const {  return ::Ifc4x1::IfcObjectiveEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x1::IfcObjective::setObjectiveQualifier(::Ifc4x1::IfcObjectiveEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcObjectiveEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x1::IfcObjective::UserDefinedQualifier() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcObjective::declaration() const { return *IFC4X1_IfcObjective_type; }
@@ -16074,7 +16074,7 @@ Ifc4x1::IfcObjective::IfcObjective(std::string v1_Name, boost::optional< std::st
 
 // Function implementations for IfcOccupant
 boost::optional< ::Ifc4x1::IfcOccupantTypeEnum::Value > Ifc4x1::IfcOccupant::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x1::IfcOccupantTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x1::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x1::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcOccupantTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x1::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x1::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcOccupantTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcOccupant::declaration() const { return *IFC4X1_IfcOccupant_type; }
@@ -16122,7 +16122,7 @@ Ifc4x1::IfcOffsetCurve3D::IfcOffsetCurve3D(::Ifc4x1::IfcCurve* v1_BasisCurve, do
 aggregate_of< ::Ifc4x1::IfcDistanceExpression >::ptr Ifc4x1::IfcOffsetCurveByDistances::OffsetValues() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x1::IfcDistanceExpression >(); }
 void Ifc4x1::IfcOffsetCurveByDistances::setOffsetValues(aggregate_of< ::Ifc4x1::IfcDistanceExpression >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcOffsetCurveByDistances::Tag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcOffsetCurveByDistances::declaration() const { return *IFC4X1_IfcOffsetCurveByDistances_type; }
@@ -16140,7 +16140,7 @@ Ifc4x1::IfcOpenShell::IfcOpenShell(aggregate_of< ::Ifc4x1::IfcFace >::ptr v1_Cfs
 
 // Function implementations for IfcOpeningElement
 boost::optional< ::Ifc4x1::IfcOpeningElementTypeEnum::Value > Ifc4x1::IfcOpeningElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcOpeningElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcOpeningElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcOpeningElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x1::IfcRelFillsElement::list::ptr Ifc4x1::IfcOpeningElement::HasFillings() const { return data_->getInverse(IFC4X1_IfcRelFillsElement_type, 4)->as<IfcRelFillsElement>(); }
 
@@ -16159,15 +16159,15 @@ Ifc4x1::IfcOpeningStandardCase::IfcOpeningStandardCase(std::string v1_GlobalId,
 
 // Function implementations for IfcOrganization
 boost::optional< std::string > Ifc4x1::IfcOrganization::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 std::string Ifc4x1::IfcOrganization::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcOrganization::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcOrganization::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcActorRole >::ptr > Ifc4x1::IfcOrganization::Roles() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x1::IfcActorRole >(); }
-void Ifc4x1::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(3,attr);} }
+void Ifc4x1::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(3,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcAddress >::ptr > Ifc4x1::IfcOrganization::Addresses() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x1::IfcAddress >(); }
-void Ifc4x1::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x1::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(4,attr);} }
+void Ifc4x1::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x1::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(4,attr);} }
 
 ::Ifc4x1::IfcOrganizationRelationship::list::ptr Ifc4x1::IfcOrganization::IsRelatedBy() const { return data_->getInverse(IFC4X1_IfcOrganizationRelationship_type, 3)->as<IfcOrganizationRelationship>(); }
 ::Ifc4x1::IfcOrganizationRelationship::list::ptr Ifc4x1::IfcOrganization::Relates() const { return data_->getInverse(IFC4X1_IfcOrganizationRelationship_type, 2)->as<IfcOrganizationRelationship>(); }
@@ -16224,7 +16224,7 @@ Ifc4x1::IfcOuterBoundaryCurve::IfcOuterBoundaryCurve(aggregate_of< ::Ifc4x1::Ifc
 
 // Function implementations for IfcOutlet
 boost::optional< ::Ifc4x1::IfcOutletTypeEnum::Value > Ifc4x1::IfcOutlet::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcOutletTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x1::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcOutletTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x1::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcOutletTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcOutlet::declaration() const { return *IFC4X1_IfcOutlet_type; }
@@ -16248,11 +16248,11 @@ void Ifc4x1::IfcOwnerHistory::setOwningUser(::Ifc4x1::IfcPersonAndOrganization*
 ::Ifc4x1::IfcApplication* Ifc4x1::IfcOwnerHistory::OwningApplication() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x1::IfcApplication>(true); }
 void Ifc4x1::IfcOwnerHistory::setOwningApplication(::Ifc4x1::IfcApplication* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x1::IfcStateEnum::Value > Ifc4x1::IfcOwnerHistory::State() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x1::IfcStateEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x1::IfcOwnerHistory::setState(boost::optional< ::Ifc4x1::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcStateEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x1::IfcOwnerHistory::setState(boost::optional< ::Ifc4x1::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcStateEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< ::Ifc4x1::IfcChangeActionEnum::Value > Ifc4x1::IfcOwnerHistory::ChangeAction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x1::IfcChangeActionEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x1::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x1::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcChangeActionEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x1::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x1::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcChangeActionEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x1::IfcOwnerHistory::LastModifiedDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x1::IfcPersonAndOrganization* Ifc4x1::IfcOwnerHistory::LastModifyingUser() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x1::IfcPersonAndOrganization>(true); }
 void Ifc4x1::IfcOwnerHistory::setLastModifyingUser(::Ifc4x1::IfcPersonAndOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x1::IfcApplication* Ifc4x1::IfcOwnerHistory::LastModifyingApplication() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcApplication>(true); }
@@ -16302,7 +16302,7 @@ Ifc4x1::IfcPcurve::IfcPcurve(::Ifc4x1::IfcSurface* v1_BasisSurface, ::Ifc4x1::If
 std::string Ifc4x1::IfcPerformanceHistory::LifeCyclePhase() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x1::IfcPerformanceHistory::setLifeCyclePhase(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x1::IfcPerformanceHistoryTypeEnum::Value > Ifc4x1::IfcPerformanceHistory::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x1::IfcPerformanceHistoryTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x1::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x1::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPerformanceHistoryTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x1::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x1::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPerformanceHistoryTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPerformanceHistory::declaration() const { return *IFC4X1_IfcPerformanceHistory_type; }
@@ -16316,9 +16316,9 @@ void Ifc4x1::IfcPermeableCoveringProperties::setOperationType(::Ifc4x1::IfcPerme
 ::Ifc4x1::IfcWindowPanelPositionEnum::Value Ifc4x1::IfcPermeableCoveringProperties::PanelPosition() const {  return ::Ifc4x1::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x1::IfcPermeableCoveringProperties::setPanelPosition(::Ifc4x1::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcPermeableCoveringProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcPermeableCoveringProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x1::IfcShapeAspect* Ifc4x1::IfcPermeableCoveringProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x1::IfcShapeAspect>(true); }
 void Ifc4x1::IfcPermeableCoveringProperties::setShapeAspectStyle(::Ifc4x1::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -16330,11 +16330,11 @@ Ifc4x1::IfcPermeableCoveringProperties::IfcPermeableCoveringProperties(std::stri
 
 // Function implementations for IfcPermit
 boost::optional< ::Ifc4x1::IfcPermitTypeEnum::Value > Ifc4x1::IfcPermit::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x1::IfcPermitTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x1::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x1::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPermitTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x1::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x1::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPermitTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPermit::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPermit::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPermit::declaration() const { return *IFC4X1_IfcPermit_type; }
@@ -16344,21 +16344,21 @@ Ifc4x1::IfcPermit::IfcPermit(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory*
 
 // Function implementations for IfcPerson
 boost::optional< std::string > Ifc4x1::IfcPerson::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPerson::FamilyName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPerson::GivenName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcPerson::MiddleNames() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcPerson::PrefixTitles() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcPerson::SuffixTitles() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcActorRole >::ptr > Ifc4x1::IfcPerson::Roles() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x1::IfcActorRole >(); }
-void Ifc4x1::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x1::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcAddress >::ptr > Ifc4x1::IfcPerson::Addresses() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x1::IfcAddress >(); }
-void Ifc4x1::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x1::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x1::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x1::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 ::Ifc4x1::IfcPersonAndOrganization::list::ptr Ifc4x1::IfcPerson::EngagedIn() const { return data_->getInverse(IFC4X1_IfcPersonAndOrganization_type, 0)->as<IfcPersonAndOrganization>(); }
 
@@ -16373,7 +16373,7 @@ void Ifc4x1::IfcPersonAndOrganization::setThePerson(::Ifc4x1::IfcPerson* v) { {I
 ::Ifc4x1::IfcOrganization* Ifc4x1::IfcPersonAndOrganization::TheOrganization() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x1::IfcOrganization>(true); }
 void Ifc4x1::IfcPersonAndOrganization::setTheOrganization(::Ifc4x1::IfcOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcActorRole >::ptr > Ifc4x1::IfcPersonAndOrganization::Roles() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x1::IfcActorRole >(); }
-void Ifc4x1::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x1::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPersonAndOrganization::declaration() const { return *IFC4X1_IfcPersonAndOrganization_type; }
@@ -16387,9 +16387,9 @@ void Ifc4x1::IfcPhysicalComplexQuantity::setHasQuantities(aggregate_of< ::Ifc4x1
 std::string Ifc4x1::IfcPhysicalComplexQuantity::Discrimination() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcPhysicalComplexQuantity::setDiscrimination(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPhysicalComplexQuantity::Quality() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPhysicalComplexQuantity::Usage() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPhysicalComplexQuantity::declaration() const { return *IFC4X1_IfcPhysicalComplexQuantity_type; }
@@ -16401,7 +16401,7 @@ Ifc4x1::IfcPhysicalComplexQuantity::IfcPhysicalComplexQuantity(std::string v1_Na
 std::string Ifc4x1::IfcPhysicalQuantity::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcPhysicalQuantity::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPhysicalQuantity::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x1::IfcExternalReferenceRelationship::list::ptr Ifc4x1::IfcPhysicalQuantity::HasExternalReferences() const { return data_->getInverse(IFC4X1_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x1::IfcPhysicalComplexQuantity::list::ptr Ifc4x1::IfcPhysicalQuantity::PartOfComplex() const { return data_->getInverse(IFC4X1_IfcPhysicalComplexQuantity_type, 2)->as<IfcPhysicalComplexQuantity>(); }
@@ -16423,9 +16423,9 @@ Ifc4x1::IfcPhysicalSimpleQuantity::IfcPhysicalSimpleQuantity(std::string v1_Name
 
 // Function implementations for IfcPile
 boost::optional< ::Ifc4x1::IfcPileTypeEnum::Value > Ifc4x1::IfcPile::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcPileTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcPile::setPredefinedType(boost::optional< ::Ifc4x1::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPileTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcPile::setPredefinedType(boost::optional< ::Ifc4x1::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPileTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x1::IfcPileConstructionEnum::Value > Ifc4x1::IfcPile::ConstructionType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x1::IfcPileConstructionEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x1::IfcPile::setConstructionType(boost::optional< ::Ifc4x1::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPileConstructionEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x1::IfcPile::setConstructionType(boost::optional< ::Ifc4x1::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPileConstructionEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPile::declaration() const { return *IFC4X1_IfcPile_type; }
@@ -16445,7 +16445,7 @@ Ifc4x1::IfcPileType::IfcPileType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHist
 
 // Function implementations for IfcPipeFitting
 boost::optional< ::Ifc4x1::IfcPipeFittingTypeEnum::Value > Ifc4x1::IfcPipeFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcPipeFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x1::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPipeFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x1::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPipeFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPipeFitting::declaration() const { return *IFC4X1_IfcPipeFitting_type; }
@@ -16465,7 +16465,7 @@ Ifc4x1::IfcPipeFittingType::IfcPipeFittingType(std::string v1_GlobalId, ::Ifc4x1
 
 // Function implementations for IfcPipeSegment
 boost::optional< ::Ifc4x1::IfcPipeSegmentTypeEnum::Value > Ifc4x1::IfcPipeSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcPipeSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x1::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPipeSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x1::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPipeSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPipeSegment::declaration() const { return *IFC4X1_IfcPipeSegment_type; }
@@ -16541,7 +16541,7 @@ Ifc4x1::IfcPlane::IfcPlane(::Ifc4x1::IfcAxis2Placement3D* v1_Position) : IfcElem
 
 // Function implementations for IfcPlate
 boost::optional< ::Ifc4x1::IfcPlateTypeEnum::Value > Ifc4x1::IfcPlate::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcPlateTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x1::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPlateTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x1::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPlateTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPlate::declaration() const { return *IFC4X1_IfcPlate_type; }
@@ -16625,11 +16625,11 @@ Ifc4x1::IfcPolygonalBoundedHalfSpace::IfcPolygonalBoundedHalfSpace(::Ifc4x1::Ifc
 
 // Function implementations for IfcPolygonalFaceSet
 boost::optional< bool > Ifc4x1::IfcPolygonalFaceSet::Closed() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x1::IfcIndexedPolygonalFace >::ptr Ifc4x1::IfcPolygonalFaceSet::Faces() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x1::IfcIndexedPolygonalFace >(); }
 void Ifc4x1::IfcPolygonalFaceSet::setFaces(aggregate_of< ::Ifc4x1::IfcIndexedPolygonalFace >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x1::IfcPolygonalFaceSet::PnIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPolygonalFaceSet::declaration() const { return *IFC4X1_IfcPolygonalFaceSet_type; }
@@ -16669,19 +16669,19 @@ Ifc4x1::IfcPositioningElement::IfcPositioningElement(std::string v1_GlobalId, ::
 
 // Function implementations for IfcPostalAddress
 boost::optional< std::string > Ifc4x1::IfcPostalAddress::InternalLocation() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcPostalAddress::AddressLines() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPostalAddress::PostalBox() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPostalAddress::Town() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPostalAddress::Region() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPostalAddress::PostalCode() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPostalAddress::Country() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPostalAddress::declaration() const { return *IFC4X1_IfcPostalAddress_type; }
@@ -16751,11 +16751,11 @@ Ifc4x1::IfcPresentationItem::IfcPresentationItem() : IfcUtil::IfcBaseEntity() {d
 std::string Ifc4x1::IfcPresentationLayerAssignment::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcPresentationLayerAssignment::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPresentationLayerAssignment::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of_instance::ptr Ifc4x1::IfcPresentationLayerAssignment::AssignedItems() const {  aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
 void Ifc4x1::IfcPresentationLayerAssignment::setAssignedItems(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPresentationLayerAssignment::Identifier() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPresentationLayerAssignment::declaration() const { return *IFC4X1_IfcPresentationLayerAssignment_type; }
@@ -16781,7 +16781,7 @@ Ifc4x1::IfcPresentationLayerWithStyle::IfcPresentationLayerWithStyle(std::string
 
 // Function implementations for IfcPresentationStyle
 boost::optional< std::string > Ifc4x1::IfcPresentationStyle::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPresentationStyle::declaration() const { return *IFC4X1_IfcPresentationStyle_type; }
@@ -16801,7 +16801,7 @@ Ifc4x1::IfcPresentationStyleAssignment::IfcPresentationStyleAssignment(aggregate
 
 // Function implementations for IfcProcedure
 boost::optional< ::Ifc4x1::IfcProcedureTypeEnum::Value > Ifc4x1::IfcProcedure::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x1::IfcProcedureTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x1::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x1::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProcedureTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x1::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x1::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProcedureTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcProcedure::declaration() const { return *IFC4X1_IfcProcedure_type; }
@@ -16821,9 +16821,9 @@ Ifc4x1::IfcProcedureType::IfcProcedureType(std::string v1_GlobalId, ::Ifc4x1::If
 
 // Function implementations for IfcProcess
 boost::optional< std::string > Ifc4x1::IfcProcess::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcProcess::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x1::IfcRelSequence::list::ptr Ifc4x1::IfcProcess::IsPredecessorTo() const { return data_->getInverse(IFC4X1_IfcRelSequence_type, 4)->as<IfcRelSequence>(); }
 ::Ifc4x1::IfcRelSequence::list::ptr Ifc4x1::IfcProcess::IsSuccessorFrom() const { return data_->getInverse(IFC4X1_IfcRelSequence_type, 5)->as<IfcRelSequence>(); }
@@ -16859,9 +16859,9 @@ Ifc4x1::IfcProductDefinitionShape::IfcProductDefinitionShape(boost::optional< st
 
 // Function implementations for IfcProductRepresentation
 boost::optional< std::string > Ifc4x1::IfcProductRepresentation::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcProductRepresentation::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x1::IfcRepresentation >::ptr Ifc4x1::IfcProductRepresentation::Representations() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x1::IfcRepresentation >(); }
 void Ifc4x1::IfcProductRepresentation::setRepresentations(aggregate_of< ::Ifc4x1::IfcRepresentation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -16875,7 +16875,7 @@ Ifc4x1::IfcProductRepresentation::IfcProductRepresentation(boost::optional< std:
 ::Ifc4x1::IfcProfileTypeEnum::Value Ifc4x1::IfcProfileDef::ProfileType() const {  return ::Ifc4x1::IfcProfileTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x1::IfcProfileDef::setProfileType(::Ifc4x1::IfcProfileTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcProfileTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcProfileDef::ProfileName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x1::IfcExternalReferenceRelationship::list::ptr Ifc4x1::IfcProfileDef::HasExternalReference() const { return data_->getInverse(IFC4X1_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x1::IfcProfileProperties::list::ptr Ifc4x1::IfcProfileDef::HasProperties() const { return data_->getInverse(IFC4X1_IfcProfileProperties_type, 3)->as<IfcProfileProperties>(); }
@@ -16913,11 +16913,11 @@ Ifc4x1::IfcProjectLibrary::IfcProjectLibrary(std::string v1_GlobalId, ::Ifc4x1::
 
 // Function implementations for IfcProjectOrder
 boost::optional< ::Ifc4x1::IfcProjectOrderTypeEnum::Value > Ifc4x1::IfcProjectOrder::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x1::IfcProjectOrderTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x1::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x1::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProjectOrderTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x1::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x1::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProjectOrderTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcProjectOrder::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcProjectOrder::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcProjectOrder::declaration() const { return *IFC4X1_IfcProjectOrder_type; }
@@ -16927,9 +16927,9 @@ Ifc4x1::IfcProjectOrder::IfcProjectOrder(std::string v1_GlobalId, ::Ifc4x1::IfcO
 
 // Function implementations for IfcProjectedCRS
 boost::optional< std::string > Ifc4x1::IfcProjectedCRS::MapProjection() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcProjectedCRS::MapZone() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x1::IfcNamedUnit* Ifc4x1::IfcProjectedCRS::MapUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcNamedUnit>(true); }
 void Ifc4x1::IfcProjectedCRS::setMapUnit(::Ifc4x1::IfcNamedUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -16941,7 +16941,7 @@ Ifc4x1::IfcProjectedCRS::IfcProjectedCRS(std::string v1_Name, boost::optional< s
 
 // Function implementations for IfcProjectionElement
 boost::optional< ::Ifc4x1::IfcProjectionElementTypeEnum::Value > Ifc4x1::IfcProjectionElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcProjectionElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProjectionElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProjectionElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcProjectionElement::declaration() const { return *IFC4X1_IfcProjectionElement_type; }
@@ -16953,7 +16953,7 @@ Ifc4x1::IfcProjectionElement::IfcProjectionElement(std::string v1_GlobalId, ::If
 std::string Ifc4x1::IfcProperty::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcProperty::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcProperty::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x1::IfcPropertySet::list::ptr Ifc4x1::IfcProperty::PartOfPset() const { return data_->getInverse(IFC4X1_IfcPropertySet_type, 4)->as<IfcPropertySet>(); }
 ::Ifc4x1::IfcPropertyDependencyRelationship::list::ptr Ifc4x1::IfcProperty::PropertyForDependance() const { return data_->getInverse(IFC4X1_IfcPropertyDependencyRelationship_type, 2)->as<IfcPropertyDependencyRelationship>(); }
@@ -17008,7 +17008,7 @@ void Ifc4x1::IfcPropertyDependencyRelationship::setDependingProperty(::Ifc4x1::I
 ::Ifc4x1::IfcProperty* Ifc4x1::IfcPropertyDependencyRelationship::DependantProperty() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcProperty>(true); }
 void Ifc4x1::IfcPropertyDependencyRelationship::setDependantProperty(::Ifc4x1::IfcProperty* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPropertyDependencyRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPropertyDependencyRelationship::declaration() const { return *IFC4X1_IfcPropertyDependencyRelationship_type; }
@@ -17018,7 +17018,7 @@ Ifc4x1::IfcPropertyDependencyRelationship::IfcPropertyDependencyRelationship(boo
 
 // Function implementations for IfcPropertyEnumeratedValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x1::IfcPropertyEnumeratedValue::EnumerationValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcPropertyEnumeration* Ifc4x1::IfcPropertyEnumeratedValue::EnumerationReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcPropertyEnumeration>(true); }
 void Ifc4x1::IfcPropertyEnumeratedValue::setEnumerationReference(::Ifc4x1::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -17044,7 +17044,7 @@ Ifc4x1::IfcPropertyEnumeration::IfcPropertyEnumeration(std::string v1_Name, aggr
 
 // Function implementations for IfcPropertyListValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x1::IfcPropertyListValue::ListValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcUnit* Ifc4x1::IfcPropertyListValue::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcUnit>(true); }
 void Ifc4x1::IfcPropertyListValue::setUnit(::Ifc4x1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -17056,7 +17056,7 @@ Ifc4x1::IfcPropertyListValue::IfcPropertyListValue(std::string v1_Name, boost::o
 
 // Function implementations for IfcPropertyReferenceValue
 boost::optional< std::string > Ifc4x1::IfcPropertyReferenceValue::UsageName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcObjectReferenceSelect* Ifc4x1::IfcPropertyReferenceValue::PropertyReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcObjectReferenceSelect>(true); }
 void Ifc4x1::IfcPropertyReferenceValue::setPropertyReference(::Ifc4x1::IfcObjectReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -17089,9 +17089,9 @@ Ifc4x1::IfcPropertySetDefinition::IfcPropertySetDefinition(std::string v1_Global
 
 // Function implementations for IfcPropertySetTemplate
 boost::optional< ::Ifc4x1::IfcPropertySetTemplateTypeEnum::Value > Ifc4x1::IfcPropertySetTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x1::IfcPropertySetTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x1::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x1::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPropertySetTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x1::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x1::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPropertySetTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPropertySetTemplate::ApplicableEntity() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 aggregate_of< ::Ifc4x1::IfcPropertyTemplate >::ptr Ifc4x1::IfcPropertySetTemplate::HasPropertyTemplates() const {  aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x1::IfcPropertyTemplate >(); }
 void Ifc4x1::IfcPropertySetTemplate::setHasPropertyTemplates(aggregate_of< ::Ifc4x1::IfcPropertyTemplate >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(6,attr);} }
 
@@ -17116,17 +17116,17 @@ Ifc4x1::IfcPropertySingleValue::IfcPropertySingleValue(std::string v1_Name, boos
 
 // Function implementations for IfcPropertyTableValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x1::IfcPropertyTableValue::DefiningValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x1::IfcPropertyTableValue::DefinedValues() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcPropertyTableValue::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x1::IfcUnit* Ifc4x1::IfcPropertyTableValue::DefiningUnit() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x1::IfcUnit>(true); }
 void Ifc4x1::IfcPropertyTableValue::setDefiningUnit(::Ifc4x1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x1::IfcUnit* Ifc4x1::IfcPropertyTableValue::DefinedUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcUnit>(true); }
 void Ifc4x1::IfcPropertyTableValue::setDefinedUnit(::Ifc4x1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x1::IfcCurveInterpolationEnum::Value > Ifc4x1::IfcPropertyTableValue::CurveInterpolation() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x1::IfcCurveInterpolationEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x1::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x1::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCurveInterpolationEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x1::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x1::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcCurveInterpolationEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPropertyTableValue::declaration() const { return *IFC4X1_IfcPropertyTableValue_type; }
@@ -17154,7 +17154,7 @@ Ifc4x1::IfcPropertyTemplateDefinition::IfcPropertyTemplateDefinition(std::string
 
 // Function implementations for IfcProtectiveDevice
 boost::optional< ::Ifc4x1::IfcProtectiveDeviceTypeEnum::Value > Ifc4x1::IfcProtectiveDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcProtectiveDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProtectiveDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProtectiveDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcProtectiveDevice::declaration() const { return *IFC4X1_IfcProtectiveDevice_type; }
@@ -17164,7 +17164,7 @@ Ifc4x1::IfcProtectiveDevice::IfcProtectiveDevice(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcProtectiveDeviceTrippingUnit
 boost::optional< ::Ifc4x1::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > Ifc4x1::IfcProtectiveDeviceTrippingUnit::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcProtectiveDeviceTrippingUnitTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x1::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x1::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcProtectiveDeviceTrippingUnit::declaration() const { return *IFC4X1_IfcProtectiveDeviceTrippingUnit_type; }
@@ -17196,7 +17196,7 @@ Ifc4x1::IfcProtectiveDeviceType::IfcProtectiveDeviceType(std::string v1_GlobalId
 ::Ifc4x1::IfcObjectTypeEnum::Value Ifc4x1::IfcProxy::ProxyType() const {  return ::Ifc4x1::IfcObjectTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x1::IfcProxy::setProxyType(::Ifc4x1::IfcObjectTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcObjectTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcProxy::Tag() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcProxy::declaration() const { return *IFC4X1_IfcProxy_type; }
@@ -17206,7 +17206,7 @@ Ifc4x1::IfcProxy::IfcProxy(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory* v
 
 // Function implementations for IfcPump
 boost::optional< ::Ifc4x1::IfcPumpTypeEnum::Value > Ifc4x1::IfcPump::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcPumpTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcPump::setPredefinedType(boost::optional< ::Ifc4x1::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPumpTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcPump::setPredefinedType(boost::optional< ::Ifc4x1::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcPumpTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcPump::declaration() const { return *IFC4X1_IfcPump_type; }
@@ -17228,7 +17228,7 @@ Ifc4x1::IfcPumpType::IfcPumpType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHist
 double Ifc4x1::IfcQuantityArea::AreaValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcQuantityArea::setAreaValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcQuantityArea::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcQuantityArea::declaration() const { return *IFC4X1_IfcQuantityArea_type; }
@@ -17240,7 +17240,7 @@ Ifc4x1::IfcQuantityArea::IfcQuantityArea(std::string v1_Name, boost::optional< s
 double Ifc4x1::IfcQuantityCount::CountValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcQuantityCount::setCountValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcQuantityCount::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcQuantityCount::declaration() const { return *IFC4X1_IfcQuantityCount_type; }
@@ -17252,7 +17252,7 @@ Ifc4x1::IfcQuantityCount::IfcQuantityCount(std::string v1_Name, boost::optional<
 double Ifc4x1::IfcQuantityLength::LengthValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcQuantityLength::setLengthValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcQuantityLength::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcQuantityLength::declaration() const { return *IFC4X1_IfcQuantityLength_type; }
@@ -17272,7 +17272,7 @@ Ifc4x1::IfcQuantitySet::IfcQuantitySet(std::string v1_GlobalId, ::Ifc4x1::IfcOwn
 double Ifc4x1::IfcQuantityTime::TimeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcQuantityTime::setTimeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcQuantityTime::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcQuantityTime::declaration() const { return *IFC4X1_IfcQuantityTime_type; }
@@ -17284,7 +17284,7 @@ Ifc4x1::IfcQuantityTime::IfcQuantityTime(std::string v1_Name, boost::optional< s
 double Ifc4x1::IfcQuantityVolume::VolumeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcQuantityVolume::setVolumeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcQuantityVolume::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcQuantityVolume::declaration() const { return *IFC4X1_IfcQuantityVolume_type; }
@@ -17296,7 +17296,7 @@ Ifc4x1::IfcQuantityVolume::IfcQuantityVolume(std::string v1_Name, boost::optiona
 double Ifc4x1::IfcQuantityWeight::WeightValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcQuantityWeight::setWeightValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcQuantityWeight::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcQuantityWeight::declaration() const { return *IFC4X1_IfcQuantityWeight_type; }
@@ -17306,7 +17306,7 @@ Ifc4x1::IfcQuantityWeight::IfcQuantityWeight(std::string v1_Name, boost::optiona
 
 // Function implementations for IfcRailing
 boost::optional< ::Ifc4x1::IfcRailingTypeEnum::Value > Ifc4x1::IfcRailing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcRailingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x1::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcRailingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x1::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcRailingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcRailing::declaration() const { return *IFC4X1_IfcRailing_type; }
@@ -17326,7 +17326,7 @@ Ifc4x1::IfcRailingType::IfcRailingType(std::string v1_GlobalId, ::Ifc4x1::IfcOwn
 
 // Function implementations for IfcRamp
 boost::optional< ::Ifc4x1::IfcRampTypeEnum::Value > Ifc4x1::IfcRamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcRampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x1::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcRampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x1::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcRampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcRamp::declaration() const { return *IFC4X1_IfcRamp_type; }
@@ -17336,7 +17336,7 @@ Ifc4x1::IfcRamp::IfcRamp(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory* v2_
 
 // Function implementations for IfcRampFlight
 boost::optional< ::Ifc4x1::IfcRampFlightTypeEnum::Value > Ifc4x1::IfcRampFlight::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcRampFlightTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x1::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcRampFlightTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x1::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcRampFlightTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcRampFlight::declaration() const { return *IFC4X1_IfcRampFlight_type; }
@@ -17388,9 +17388,9 @@ Ifc4x1::IfcRationalBSplineSurfaceWithKnots::IfcRationalBSplineSurfaceWithKnots(i
 double Ifc4x1::IfcRectangleHollowProfileDef::WallThickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x1::IfcRectangleHollowProfileDef::setWallThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcRectangleHollowProfileDef::InnerFilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcRectangleHollowProfileDef::OuterFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcRectangleHollowProfileDef::declaration() const { return *IFC4X1_IfcRectangleHollowProfileDef_type; }
@@ -17450,19 +17450,19 @@ Ifc4x1::IfcRectangularTrimmedSurface::IfcRectangularTrimmedSurface(::Ifc4x1::Ifc
 ::Ifc4x1::IfcRecurrenceTypeEnum::Value Ifc4x1::IfcRecurrencePattern::RecurrenceType() const {  return ::Ifc4x1::IfcRecurrenceTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x1::IfcRecurrencePattern::setRecurrenceType(::Ifc4x1::IfcRecurrenceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcRecurrenceTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x1::IfcRecurrencePattern::DayComponent() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x1::IfcRecurrencePattern::WeekdayComponent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x1::IfcRecurrencePattern::MonthComponent() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x1::IfcRecurrencePattern::Position() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< int > Ifc4x1::IfcRecurrencePattern::Interval() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } int v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x1::IfcRecurrencePattern::Occurrences() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcTimePeriod >::ptr > Ifc4x1::IfcRecurrencePattern::TimePeriods() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x1::IfcTimePeriod >(); }
-void Ifc4x1::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x1::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x1::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x1::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcRecurrencePattern::declaration() const { return *IFC4X1_IfcRecurrencePattern_type; }
@@ -17472,13 +17472,13 @@ Ifc4x1::IfcRecurrencePattern::IfcRecurrencePattern(::Ifc4x1::IfcRecurrenceTypeEn
 
 // Function implementations for IfcReference
 boost::optional< std::string > Ifc4x1::IfcReference::TypeIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcReference::AttributeIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcReference::InstanceName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x1::IfcReference::ListPositions() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x1::IfcReference* Ifc4x1::IfcReference::InnerReference() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x1::IfcReference>(true); }
 void Ifc4x1::IfcReference::setInnerReference(::Ifc4x1::IfcReference* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -17490,9 +17490,9 @@ Ifc4x1::IfcReference::IfcReference(boost::optional< std::string > v1_TypeIdentif
 
 // Function implementations for IfcReferent
 boost::optional< ::Ifc4x1::IfcReferentTypeEnum::Value > Ifc4x1::IfcReferent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x1::IfcReferentTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x1::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x1::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReferentTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x1::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x1::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReferentTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcReferent::RestartDistance() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcReferent::declaration() const { return *IFC4X1_IfcReferent_type; }
@@ -17518,13 +17518,13 @@ void Ifc4x1::IfcReinforcementBarProperties::setTotalCrossSectionArea(double v) {
 std::string Ifc4x1::IfcReinforcementBarProperties::SteelGrade() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcReinforcementBarProperties::setSteelGrade(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x1::IfcReinforcingBarSurfaceEnum::Value > Ifc4x1::IfcReinforcementBarProperties::BarSurface() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x1::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x1::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x1::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcementBarProperties::EffectiveDepth() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcementBarProperties::NominalBarDiameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcementBarProperties::BarCount() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcReinforcementBarProperties::declaration() const { return *IFC4X1_IfcReinforcementBarProperties_type; }
@@ -17534,7 +17534,7 @@ Ifc4x1::IfcReinforcementBarProperties::IfcReinforcementBarProperties(double v1_T
 
 // Function implementations for IfcReinforcementDefinitionProperties
 boost::optional< std::string > Ifc4x1::IfcReinforcementDefinitionProperties::DefinitionType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x1::IfcSectionReinforcementProperties >::ptr Ifc4x1::IfcReinforcementDefinitionProperties::ReinforcementSectionDefinitions() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x1::IfcSectionReinforcementProperties >(); }
 void Ifc4x1::IfcReinforcementDefinitionProperties::setReinforcementSectionDefinitions(aggregate_of< ::Ifc4x1::IfcSectionReinforcementProperties >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -17546,15 +17546,15 @@ Ifc4x1::IfcReinforcementDefinitionProperties::IfcReinforcementDefinitionProperti
 
 // Function implementations for IfcReinforcingBar
 boost::optional< double > Ifc4x1::IfcReinforcingBar::NominalDiameter() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingBar::CrossSectionArea() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingBar::BarLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x1::IfcReinforcingBarTypeEnum::Value > Ifc4x1::IfcReinforcingBar::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x1::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x1::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x1::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReinforcingBarTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x1::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x1::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReinforcingBarTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x1::IfcReinforcingBarSurfaceEnum::Value > Ifc4x1::IfcReinforcingBar::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x1::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x1::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x1::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcReinforcingBar::declaration() const { return *IFC4X1_IfcReinforcingBar_type; }
@@ -17566,17 +17566,17 @@ Ifc4x1::IfcReinforcingBar::IfcReinforcingBar(std::string v1_GlobalId, ::Ifc4x1::
 ::Ifc4x1::IfcReinforcingBarTypeEnum::Value Ifc4x1::IfcReinforcingBarType::PredefinedType() const {  return ::Ifc4x1::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x1::IfcReinforcingBarType::setPredefinedType(::Ifc4x1::IfcReinforcingBarTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcReinforcingBarTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingBarType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingBarType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingBarType::BarLength() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x1::IfcReinforcingBarSurfaceEnum::Value > Ifc4x1::IfcReinforcingBarType::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x1::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x1::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x1::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x1::IfcReinforcingBarType::BendingShapeCode() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x1::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x1::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x1::IfcReinforcingBarType::BendingParameters() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(15); return v; }
-void Ifc4x1::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x1::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcReinforcingBarType::declaration() const { return *IFC4X1_IfcReinforcingBarType_type; }
@@ -17586,7 +17586,7 @@ Ifc4x1::IfcReinforcingBarType::IfcReinforcingBarType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcReinforcingElement
 boost::optional< std::string > Ifc4x1::IfcReinforcingElement::SteelGrade() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcReinforcingElement::declaration() const { return *IFC4X1_IfcReinforcingElement_type; }
@@ -17604,23 +17604,23 @@ Ifc4x1::IfcReinforcingElementType::IfcReinforcingElementType(std::string v1_Glob
 
 // Function implementations for IfcReinforcingMesh
 boost::optional< double > Ifc4x1::IfcReinforcingMesh::MeshLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMesh::MeshWidth() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMesh::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMesh::TransverseBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMesh::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x1::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x1::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMesh::TransverseBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x1::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x1::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMesh::LongitudinalBarSpacing() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x1::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x1::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMesh::TransverseBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x1::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x1::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< ::Ifc4x1::IfcReinforcingMeshTypeEnum::Value > Ifc4x1::IfcReinforcingMesh::PredefinedType() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } return ::Ifc4x1::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(17)); }
-void Ifc4x1::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x1::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReinforcingMeshTypeEnum::ToString(*v)));data_->setArgument(17,attr);} }
+void Ifc4x1::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x1::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcReinforcingMeshTypeEnum::ToString(*v)));}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcReinforcingMesh::declaration() const { return *IFC4X1_IfcReinforcingMesh_type; }
@@ -17632,25 +17632,25 @@ Ifc4x1::IfcReinforcingMesh::IfcReinforcingMesh(std::string v1_GlobalId, ::Ifc4x1
 ::Ifc4x1::IfcReinforcingMeshTypeEnum::Value Ifc4x1::IfcReinforcingMeshType::PredefinedType() const {  return ::Ifc4x1::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x1::IfcReinforcingMeshType::setPredefinedType(::Ifc4x1::IfcReinforcingMeshTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcReinforcingMeshTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMeshType::MeshLength() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMeshType::MeshWidth() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMeshType::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMeshType::TransverseBarNominalDiameter() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x1::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x1::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMeshType::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x1::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x1::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMeshType::TransverseBarCrossSectionArea() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x1::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x1::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMeshType::LongitudinalBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x1::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x1::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x1::IfcReinforcingMeshType::TransverseBarSpacing() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x1::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x1::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x1::IfcReinforcingMeshType::BendingShapeCode() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x1::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x1::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x1::IfcReinforcingMeshType::BendingParameters() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(19); return v; }
-void Ifc4x1::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x1::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcReinforcingMeshType::declaration() const { return *IFC4X1_IfcReinforcingMeshType_type; }
@@ -17674,7 +17674,7 @@ Ifc4x1::IfcRelAggregates::IfcRelAggregates(std::string v1_GlobalId, ::Ifc4x1::If
 aggregate_of< ::Ifc4x1::IfcObjectDefinition >::ptr Ifc4x1::IfcRelAssigns::RelatedObjects() const {  aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x1::IfcObjectDefinition >(); }
 void Ifc4x1::IfcRelAssigns::setRelatedObjects(aggregate_of< ::Ifc4x1::IfcObjectDefinition >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x1::IfcObjectTypeEnum::Value > Ifc4x1::IfcRelAssigns::RelatedObjectsType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x1::IfcObjectTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x1::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x1::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcObjectTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x1::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x1::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcObjectTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcRelAssigns::declaration() const { return *IFC4X1_IfcRelAssigns_type; }
@@ -17788,7 +17788,7 @@ Ifc4x1::IfcRelAssociatesClassification::IfcRelAssociatesClassification(std::stri
 
 // Function implementations for IfcRelAssociatesConstraint
 boost::optional< std::string > Ifc4x1::IfcRelAssociatesConstraint::Intent() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x1::IfcConstraint* Ifc4x1::IfcRelAssociatesConstraint::RelatingConstraint() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcConstraint>(true); }
 void Ifc4x1::IfcRelAssociatesConstraint::setRelatingConstraint(::Ifc4x1::IfcConstraint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -17914,7 +17914,7 @@ void Ifc4x1::IfcRelConnectsStructuralMember::setAppliedCondition(::Ifc4x1::IfcBo
 ::Ifc4x1::IfcStructuralConnectionCondition* Ifc4x1::IfcRelConnectsStructuralMember::AdditionalConditions() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x1::IfcStructuralConnectionCondition>(true); }
 void Ifc4x1::IfcRelConnectsStructuralMember::setAdditionalConditions(::Ifc4x1::IfcStructuralConnectionCondition* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcRelConnectsStructuralMember::SupportedLength() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x1::IfcAxis2Placement3D* Ifc4x1::IfcRelConnectsStructuralMember::ConditionCoordinateSystem() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x1::IfcAxis2Placement3D>(true); }
 void Ifc4x1::IfcRelConnectsStructuralMember::setConditionCoordinateSystem(::Ifc4x1::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -17938,7 +17938,7 @@ Ifc4x1::IfcRelConnectsWithEccentricity::IfcRelConnectsWithEccentricity(std::stri
 aggregate_of< ::Ifc4x1::IfcElement >::ptr Ifc4x1::IfcRelConnectsWithRealizingElements::RealizingElements() const {  aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x1::IfcElement >(); }
 void Ifc4x1::IfcRelConnectsWithRealizingElements::setRealizingElements(aggregate_of< ::Ifc4x1::IfcElement >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcRelConnectsWithRealizingElements::ConnectionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcRelConnectsWithRealizingElements::declaration() const { return *IFC4X1_IfcRelConnectsWithRealizingElements_type; }
@@ -18090,7 +18090,7 @@ void Ifc4x1::IfcRelInterferesElements::setRelatedElement(::Ifc4x1::IfcElement* v
 ::Ifc4x1::IfcConnectionGeometry* Ifc4x1::IfcRelInterferesElements::InterferenceGeometry() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcConnectionGeometry>(true); }
 void Ifc4x1::IfcRelInterferesElements::setInterferenceGeometry(::Ifc4x1::IfcConnectionGeometry* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcRelInterferesElements::InterferenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::logic::tribool Ifc4x1::IfcRelInterferesElements::ImpliedOrder() const {  boost::logic::tribool v = *data_->getArgument(8); return v; }
 void Ifc4x1::IfcRelInterferesElements::setImpliedOrder(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -18144,9 +18144,9 @@ void Ifc4x1::IfcRelSequence::setRelatedProcess(::Ifc4x1::IfcProcess* v) { {IfcWr
 ::Ifc4x1::IfcLagTime* Ifc4x1::IfcRelSequence::TimeLag() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcLagTime>(true); }
 void Ifc4x1::IfcRelSequence::setTimeLag(::Ifc4x1::IfcLagTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x1::IfcSequenceEnum::Value > Ifc4x1::IfcRelSequence::SequenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSequenceEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x1::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x1::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSequenceEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x1::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x1::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSequenceEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcRelSequence::UserDefinedSequenceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcRelSequence::declaration() const { return *IFC4X1_IfcRelSequence_type; }
@@ -18240,9 +18240,9 @@ Ifc4x1::IfcReparametrisedCompositeCurveSegment::IfcReparametrisedCompositeCurveS
 ::Ifc4x1::IfcRepresentationContext* Ifc4x1::IfcRepresentation::ContextOfItems() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x1::IfcRepresentationContext>(true); }
 void Ifc4x1::IfcRepresentation::setContextOfItems(::Ifc4x1::IfcRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcRepresentation::RepresentationIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcRepresentation::RepresentationType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc4x1::IfcRepresentationItem >::ptr Ifc4x1::IfcRepresentation::Items() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x1::IfcRepresentationItem >(); }
 void Ifc4x1::IfcRepresentation::setItems(aggregate_of< ::Ifc4x1::IfcRepresentationItem >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 
@@ -18257,9 +18257,9 @@ Ifc4x1::IfcRepresentation::IfcRepresentation(::Ifc4x1::IfcRepresentationContext*
 
 // Function implementations for IfcRepresentationContext
 boost::optional< std::string > Ifc4x1::IfcRepresentationContext::ContextIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcRepresentationContext::ContextType() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x1::IfcRepresentation::list::ptr Ifc4x1::IfcRepresentationContext::RepresentationsInContext() const { return data_->getInverse(IFC4X1_IfcRepresentation_type, 0)->as<IfcRepresentation>(); }
 
@@ -18294,9 +18294,9 @@ Ifc4x1::IfcRepresentationMap::IfcRepresentationMap(::Ifc4x1::IfcAxis2Placement*
 
 // Function implementations for IfcResource
 boost::optional< std::string > Ifc4x1::IfcResource::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResource::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x1::IfcRelAssignsToResource::list::ptr Ifc4x1::IfcResource::ResourceOf() const { return data_->getInverse(IFC4X1_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -18331,9 +18331,9 @@ Ifc4x1::IfcResourceConstraintRelationship::IfcResourceConstraintRelationship(boo
 
 // Function implementations for IfcResourceLevelRelationship
 boost::optional< std::string > Ifc4x1::IfcResourceLevelRelationship::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResourceLevelRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcResourceLevelRelationship::declaration() const { return *IFC4X1_IfcResourceLevelRelationship_type; }
@@ -18343,35 +18343,35 @@ Ifc4x1::IfcResourceLevelRelationship::IfcResourceLevelRelationship(boost::option
 
 // Function implementations for IfcResourceTime
 boost::optional< std::string > Ifc4x1::IfcResourceTime::ScheduleWork() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcResourceTime::ScheduleUsage() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResourceTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResourceTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResourceTime::ScheduleContour() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResourceTime::LevelingDelay() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< bool > Ifc4x1::IfcResourceTime::IsOverAllocated() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResourceTime::StatusTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResourceTime::ActualWork() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x1::IfcResourceTime::ActualUsage() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResourceTime::ActualStart() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x1::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x1::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResourceTime::ActualFinish() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x1::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x1::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x1::IfcResourceTime::RemainingWork() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x1::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x1::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x1::IfcResourceTime::RemainingUsage() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x1::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x1::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x1::IfcResourceTime::Completion() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x1::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x1::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcResourceTime::declaration() const { return *IFC4X1_IfcResourceTime_type; }
@@ -18427,7 +18427,7 @@ Ifc4x1::IfcRightCircularCylinder::IfcRightCircularCylinder(::Ifc4x1::IfcAxis2Pla
 
 // Function implementations for IfcRoof
 boost::optional< ::Ifc4x1::IfcRoofTypeEnum::Value > Ifc4x1::IfcRoof::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcRoofTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x1::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcRoofTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x1::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcRoofTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcRoof::declaration() const { return *IFC4X1_IfcRoof_type; }
@@ -18451,9 +18451,9 @@ void Ifc4x1::IfcRoot::setGlobalId(std::string v) { {IfcWrite::IfcWriteArgument*
 ::Ifc4x1::IfcOwnerHistory* Ifc4x1::IfcRoot::OwnerHistory() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x1::IfcOwnerHistory>(true); }
 void Ifc4x1::IfcRoot::setOwnerHistory(::Ifc4x1::IfcOwnerHistory* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcRoot::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x1::IfcRoot::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcRoot::declaration() const { return *IFC4X1_IfcRoot_type; }
@@ -18473,7 +18473,7 @@ Ifc4x1::IfcRoundedRectangleProfileDef::IfcRoundedRectangleProfileDef(::Ifc4x1::I
 
 // Function implementations for IfcSIUnit
 boost::optional< ::Ifc4x1::IfcSIPrefix::Value > Ifc4x1::IfcSIUnit::Prefix() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSIPrefix::FromString(*data_->getArgument(2)); }
-void Ifc4x1::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x1::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSIPrefix::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x1::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x1::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSIPrefix::ToString(*v)));}data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcSIUnitName::Value Ifc4x1::IfcSIUnit::Name() const {  return ::Ifc4x1::IfcSIUnitName::FromString(*data_->getArgument(3)); }
 void Ifc4x1::IfcSIUnit::setName(::Ifc4x1::IfcSIUnitName::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcSIUnitName::ToString(v)));data_->setArgument(3,attr);} }
 
@@ -18485,7 +18485,7 @@ Ifc4x1::IfcSIUnit::IfcSIUnit(::Ifc4x1::IfcUnitEnum::Value v2_UnitType, boost::op
 
 // Function implementations for IfcSanitaryTerminal
 boost::optional< ::Ifc4x1::IfcSanitaryTerminalTypeEnum::Value > Ifc4x1::IfcSanitaryTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSanitaryTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x1::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSanitaryTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x1::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSanitaryTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSanitaryTerminal::declaration() const { return *IFC4X1_IfcSanitaryTerminal_type; }
@@ -18505,11 +18505,11 @@ Ifc4x1::IfcSanitaryTerminalType::IfcSanitaryTerminalType(std::string v1_GlobalId
 
 // Function implementations for IfcSchedulingTime
 boost::optional< std::string > Ifc4x1::IfcSchedulingTime::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< ::Ifc4x1::IfcDataOriginEnum::Value > Ifc4x1::IfcSchedulingTime::DataOrigin() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } return ::Ifc4x1::IfcDataOriginEnum::FromString(*data_->getArgument(1)); }
-void Ifc4x1::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x1::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDataOriginEnum::ToString(*v)));data_->setArgument(1,attr);} }
+void Ifc4x1::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x1::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcDataOriginEnum::ToString(*v)));}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcSchedulingTime::UserDefinedDataOrigin() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSchedulingTime::declaration() const { return *IFC4X1_IfcSchedulingTime_type; }
@@ -18545,7 +18545,7 @@ void Ifc4x1::IfcSectionReinforcementProperties::setLongitudinalStartPosition(dou
 double Ifc4x1::IfcSectionReinforcementProperties::LongitudinalEndPosition() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcSectionReinforcementProperties::setLongitudinalEndPosition(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcSectionReinforcementProperties::TransversePosition() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcReinforcingBarRoleEnum::Value Ifc4x1::IfcSectionReinforcementProperties::ReinforcementRole() const {  return ::Ifc4x1::IfcReinforcingBarRoleEnum::FromString(*data_->getArgument(3)); }
 void Ifc4x1::IfcSectionReinforcementProperties::setReinforcementRole(::Ifc4x1::IfcReinforcingBarRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcReinforcingBarRoleEnum::ToString(v)));data_->setArgument(3,attr);} }
 ::Ifc4x1::IfcSectionProperties* Ifc4x1::IfcSectionReinforcementProperties::SectionDefinition() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x1::IfcSectionProperties>(true); }
@@ -18599,7 +18599,7 @@ Ifc4x1::IfcSectionedSpine::IfcSectionedSpine(::Ifc4x1::IfcCompositeCurve* v1_Spi
 
 // Function implementations for IfcSensor
 boost::optional< ::Ifc4x1::IfcSensorTypeEnum::Value > Ifc4x1::IfcSensor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSensorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x1::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSensorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x1::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSensorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSensor::declaration() const { return *IFC4X1_IfcSensor_type; }
@@ -18619,7 +18619,7 @@ Ifc4x1::IfcSensorType::IfcSensorType(std::string v1_GlobalId, ::Ifc4x1::IfcOwner
 
 // Function implementations for IfcShadingDevice
 boost::optional< ::Ifc4x1::IfcShadingDeviceTypeEnum::Value > Ifc4x1::IfcShadingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcShadingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcShadingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcShadingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcShadingDevice::declaration() const { return *IFC4X1_IfcShadingDevice_type; }
@@ -18641,9 +18641,9 @@ Ifc4x1::IfcShadingDeviceType::IfcShadingDeviceType(std::string v1_GlobalId, ::If
 aggregate_of< ::Ifc4x1::IfcShapeModel >::ptr Ifc4x1::IfcShapeAspect::ShapeRepresentations() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x1::IfcShapeModel >(); }
 void Ifc4x1::IfcShapeAspect::setShapeRepresentations(aggregate_of< ::Ifc4x1::IfcShapeModel >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcShapeAspect::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcShapeAspect::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::logic::tribool Ifc4x1::IfcShapeAspect::ProductDefinitional() const {  boost::logic::tribool v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcShapeAspect::setProductDefinitional(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x1::IfcProductRepresentationSelect* Ifc4x1::IfcShapeAspect::PartOfProductDefinitionShape() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x1::IfcProductRepresentationSelect>(true); }
@@ -18693,11 +18693,11 @@ Ifc4x1::IfcSimpleProperty::IfcSimpleProperty(std::string v1_Name, boost::optiona
 
 // Function implementations for IfcSimplePropertyTemplate
 boost::optional< ::Ifc4x1::IfcSimplePropertyTemplateTypeEnum::Value > Ifc4x1::IfcSimplePropertyTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSimplePropertyTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x1::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x1::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x1::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x1::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcSimplePropertyTemplate::PrimaryMeasureType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcSimplePropertyTemplate::SecondaryMeasureType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x1::IfcPropertyEnumeration* Ifc4x1::IfcSimplePropertyTemplate::Enumerators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x1::IfcPropertyEnumeration>(true); }
 void Ifc4x1::IfcSimplePropertyTemplate::setEnumerators(::Ifc4x1::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x1::IfcUnit* Ifc4x1::IfcSimplePropertyTemplate::PrimaryUnit() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x1::IfcUnit>(true); }
@@ -18705,9 +18705,9 @@ void Ifc4x1::IfcSimplePropertyTemplate::setPrimaryUnit(::Ifc4x1::IfcUnit* v) { {
 ::Ifc4x1::IfcUnit* Ifc4x1::IfcSimplePropertyTemplate::SecondaryUnit() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x1::IfcUnit>(true); }
 void Ifc4x1::IfcSimplePropertyTemplate::setSecondaryUnit(::Ifc4x1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x1::IfcSimplePropertyTemplate::Expression() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x1::IfcStateEnum::Value > Ifc4x1::IfcSimplePropertyTemplate::AccessState() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x1::IfcStateEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x1::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x1::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcStateEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x1::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x1::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcStateEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSimplePropertyTemplate::declaration() const { return *IFC4X1_IfcSimplePropertyTemplate_type; }
@@ -18717,13 +18717,13 @@ Ifc4x1::IfcSimplePropertyTemplate::IfcSimplePropertyTemplate(std::string v1_Glob
 
 // Function implementations for IfcSite
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x1::IfcSite::RefLatitude() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x1::IfcSite::RefLongitude() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcSite::RefElevation() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x1::IfcSite::LandTitleNumber() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x1::IfcPostalAddress* Ifc4x1::IfcSite::SiteAddress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x1::IfcPostalAddress>(true); }
 void Ifc4x1::IfcSite::setSiteAddress(::Ifc4x1::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -18735,7 +18735,7 @@ Ifc4x1::IfcSite::IfcSite(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory* v2_
 
 // Function implementations for IfcSlab
 boost::optional< ::Ifc4x1::IfcSlabTypeEnum::Value > Ifc4x1::IfcSlab::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSlabTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x1::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSlabTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x1::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSlabTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSlab::declaration() const { return *IFC4X1_IfcSlab_type; }
@@ -18771,11 +18771,11 @@ Ifc4x1::IfcSlabType::IfcSlabType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHist
 
 // Function implementations for IfcSlippageConnectionCondition
 boost::optional< double > Ifc4x1::IfcSlippageConnectionCondition::SlippageX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcSlippageConnectionCondition::SlippageY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcSlippageConnectionCondition::SlippageZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSlippageConnectionCondition::declaration() const { return *IFC4X1_IfcSlippageConnectionCondition_type; }
@@ -18785,7 +18785,7 @@ Ifc4x1::IfcSlippageConnectionCondition::IfcSlippageConnectionCondition(boost::op
 
 // Function implementations for IfcSolarDevice
 boost::optional< ::Ifc4x1::IfcSolarDeviceTypeEnum::Value > Ifc4x1::IfcSolarDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSolarDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSolarDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSolarDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSolarDevice::declaration() const { return *IFC4X1_IfcSolarDevice_type; }
@@ -18813,9 +18813,9 @@ Ifc4x1::IfcSolidModel::IfcSolidModel() : IfcGeometricRepresentationItem((IfcEnti
 
 // Function implementations for IfcSpace
 boost::optional< ::Ifc4x1::IfcSpaceTypeEnum::Value > Ifc4x1::IfcSpace::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x1::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x1::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSpaceTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x1::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x1::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSpaceTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcSpace::ElevationWithFlooring() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 ::Ifc4x1::IfcRelCoversSpaces::list::ptr Ifc4x1::IfcSpace::HasCoverings() const { return data_->getInverse(IFC4X1_IfcRelCoversSpaces_type, 4)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x1::IfcRelSpaceBoundary::list::ptr Ifc4x1::IfcSpace::BoundedBy() const { return data_->getInverse(IFC4X1_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
@@ -18827,7 +18827,7 @@ Ifc4x1::IfcSpace::IfcSpace(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory* v
 
 // Function implementations for IfcSpaceHeater
 boost::optional< ::Ifc4x1::IfcSpaceHeaterTypeEnum::Value > Ifc4x1::IfcSpaceHeater::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSpaceHeaterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x1::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSpaceHeaterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x1::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSpaceHeaterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSpaceHeater::declaration() const { return *IFC4X1_IfcSpaceHeater_type; }
@@ -18849,7 +18849,7 @@ Ifc4x1::IfcSpaceHeaterType::IfcSpaceHeaterType(std::string v1_GlobalId, ::Ifc4x1
 ::Ifc4x1::IfcSpaceTypeEnum::Value Ifc4x1::IfcSpaceType::PredefinedType() const {  return ::Ifc4x1::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x1::IfcSpaceType::setPredefinedType(::Ifc4x1::IfcSpaceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcSpaceTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x1::IfcSpaceType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSpaceType::declaration() const { return *IFC4X1_IfcSpaceType_type; }
@@ -18859,7 +18859,7 @@ Ifc4x1::IfcSpaceType::IfcSpaceType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHi
 
 // Function implementations for IfcSpatialElement
 boost::optional< std::string > Ifc4x1::IfcSpatialElement::LongName() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x1::IfcRelContainedInSpatialStructure::list::ptr Ifc4x1::IfcSpatialElement::ContainsElements() const { return data_->getInverse(IFC4X1_IfcRelContainedInSpatialStructure_type, 5)->as<IfcRelContainedInSpatialStructure>(); }
 ::Ifc4x1::IfcRelServicesBuildings::list::ptr Ifc4x1::IfcSpatialElement::ServicedBySystems() const { return data_->getInverse(IFC4X1_IfcRelServicesBuildings_type, 5)->as<IfcRelServicesBuildings>(); }
@@ -18872,7 +18872,7 @@ Ifc4x1::IfcSpatialElement::IfcSpatialElement(std::string v1_GlobalId, ::Ifc4x1::
 
 // Function implementations for IfcSpatialElementType
 boost::optional< std::string > Ifc4x1::IfcSpatialElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSpatialElementType::declaration() const { return *IFC4X1_IfcSpatialElementType_type; }
@@ -18882,7 +18882,7 @@ Ifc4x1::IfcSpatialElementType::IfcSpatialElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcSpatialStructureElement
 boost::optional< ::Ifc4x1::IfcElementCompositionEnum::Value > Ifc4x1::IfcSpatialStructureElement::CompositionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcElementCompositionEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x1::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElementCompositionEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x1::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcElementCompositionEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSpatialStructureElement::declaration() const { return *IFC4X1_IfcSpatialStructureElement_type; }
@@ -18900,7 +18900,7 @@ Ifc4x1::IfcSpatialStructureElementType::IfcSpatialStructureElementType(std::stri
 
 // Function implementations for IfcSpatialZone
 boost::optional< ::Ifc4x1::IfcSpatialZoneTypeEnum::Value > Ifc4x1::IfcSpatialZone::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x1::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSpatialZoneTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x1::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSpatialZoneTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSpatialZone::declaration() const { return *IFC4X1_IfcSpatialZone_type; }
@@ -18912,7 +18912,7 @@ Ifc4x1::IfcSpatialZone::IfcSpatialZone(std::string v1_GlobalId, ::Ifc4x1::IfcOwn
 ::Ifc4x1::IfcSpatialZoneTypeEnum::Value Ifc4x1::IfcSpatialZoneType::PredefinedType() const {  return ::Ifc4x1::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x1::IfcSpatialZoneType::setPredefinedType(::Ifc4x1::IfcSpatialZoneTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcSpatialZoneTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x1::IfcSpatialZoneType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSpatialZoneType::declaration() const { return *IFC4X1_IfcSpatialZoneType_type; }
@@ -18942,7 +18942,7 @@ Ifc4x1::IfcSphericalSurface::IfcSphericalSurface(::Ifc4x1::IfcAxis2Placement3D*
 
 // Function implementations for IfcStackTerminal
 boost::optional< ::Ifc4x1::IfcStackTerminalTypeEnum::Value > Ifc4x1::IfcStackTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcStackTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x1::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcStackTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x1::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcStackTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStackTerminal::declaration() const { return *IFC4X1_IfcStackTerminal_type; }
@@ -18962,7 +18962,7 @@ Ifc4x1::IfcStackTerminalType::IfcStackTerminalType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcStair
 boost::optional< ::Ifc4x1::IfcStairTypeEnum::Value > Ifc4x1::IfcStair::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcStairTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcStair::setPredefinedType(boost::optional< ::Ifc4x1::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcStairTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcStair::setPredefinedType(boost::optional< ::Ifc4x1::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcStairTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStair::declaration() const { return *IFC4X1_IfcStair_type; }
@@ -18972,15 +18972,15 @@ Ifc4x1::IfcStair::IfcStair(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory* v
 
 // Function implementations for IfcStairFlight
 boost::optional< int > Ifc4x1::IfcStairFlight::NumberOfRisers() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } int v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< int > Ifc4x1::IfcStairFlight::NumberOfTreads() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } int v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcStairFlight::RiserHeight() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcStairFlight::TreadLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x1::IfcStairFlightTypeEnum::Value > Ifc4x1::IfcStairFlight::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x1::IfcStairFlightTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x1::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x1::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcStairFlightTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x1::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x1::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcStairFlightTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStairFlight::declaration() const { return *IFC4X1_IfcStairFlight_type; }
@@ -19010,7 +19010,7 @@ Ifc4x1::IfcStairType::IfcStairType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHi
 
 // Function implementations for IfcStructuralAction
 boost::optional< bool > Ifc4x1::IfcStructuralAction::DestabilizingLoad() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralAction::declaration() const { return *IFC4X1_IfcStructuralAction_type; }
@@ -19037,9 +19037,9 @@ void Ifc4x1::IfcStructuralAnalysisModel::setPredefinedType(::Ifc4x1::IfcAnalysis
 ::Ifc4x1::IfcAxis2Placement3D* Ifc4x1::IfcStructuralAnalysisModel::OrientationOf2DPlane() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcAxis2Placement3D>(true); }
 void Ifc4x1::IfcStructuralAnalysisModel::setOrientationOf2DPlane(::Ifc4x1::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcStructuralLoadGroup >::ptr > Ifc4x1::IfcStructuralAnalysisModel::LoadedBy() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x1::IfcStructuralLoadGroup >(); }
-void Ifc4x1::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x1::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x1::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x1::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcStructuralResultGroup >::ptr > Ifc4x1::IfcStructuralAnalysisModel::HasResults() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x1::IfcStructuralResultGroup >(); }
-void Ifc4x1::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x1::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x1::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x1::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x1::IfcObjectPlacement* Ifc4x1::IfcStructuralAnalysisModel::SharedPlacement() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x1::IfcObjectPlacement>(true); }
 void Ifc4x1::IfcStructuralAnalysisModel::setSharedPlacement(::Ifc4x1::IfcObjectPlacement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -19062,7 +19062,7 @@ Ifc4x1::IfcStructuralConnection::IfcStructuralConnection(std::string v1_GlobalId
 
 // Function implementations for IfcStructuralConnectionCondition
 boost::optional< std::string > Ifc4x1::IfcStructuralConnectionCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralConnectionCondition::declaration() const { return *IFC4X1_IfcStructuralConnectionCondition_type; }
@@ -19072,7 +19072,7 @@ Ifc4x1::IfcStructuralConnectionCondition::IfcStructuralConnectionCondition(boost
 
 // Function implementations for IfcStructuralCurveAction
 boost::optional< ::Ifc4x1::IfcProjectedOrTrueLengthEnum::Value > Ifc4x1::IfcStructuralCurveAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x1::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x1::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x1::IfcStructuralCurveActivityTypeEnum::Value Ifc4x1::IfcStructuralCurveAction::PredefinedType() const {  return ::Ifc4x1::IfcStructuralCurveActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x1::IfcStructuralCurveAction::setPredefinedType(::Ifc4x1::IfcStructuralCurveActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcStructuralCurveActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -19141,7 +19141,7 @@ Ifc4x1::IfcStructuralLinearAction::IfcStructuralLinearAction(std::string v1_Glob
 
 // Function implementations for IfcStructuralLoad
 boost::optional< std::string > Ifc4x1::IfcStructuralLoad::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralLoad::declaration() const { return *IFC4X1_IfcStructuralLoad_type; }
@@ -19151,7 +19151,7 @@ Ifc4x1::IfcStructuralLoad::IfcStructuralLoad(boost::optional< std::string > v1_N
 
 // Function implementations for IfcStructuralLoadCase
 boost::optional< std::vector< double > /*[3:3]*/ > Ifc4x1::IfcStructuralLoadCase::SelfWeightCoefficients() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< double > /*[3:3]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralLoadCase::declaration() const { return *IFC4X1_IfcStructuralLoadCase_type; }
@@ -19163,7 +19163,7 @@ Ifc4x1::IfcStructuralLoadCase::IfcStructuralLoadCase(std::string v1_GlobalId, ::
 aggregate_of< ::Ifc4x1::IfcStructuralLoadOrResult >::ptr Ifc4x1::IfcStructuralLoadConfiguration::Values() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x1::IfcStructuralLoadOrResult >(); }
 void Ifc4x1::IfcStructuralLoadConfiguration::setValues(aggregate_of< ::Ifc4x1::IfcStructuralLoadOrResult >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::vector< std::vector< double > > > Ifc4x1::IfcStructuralLoadConfiguration::Locations() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralLoadConfiguration::declaration() const { return *IFC4X1_IfcStructuralLoadConfiguration_type; }
@@ -19179,9 +19179,9 @@ void Ifc4x1::IfcStructuralLoadGroup::setActionType(::Ifc4x1::IfcActionTypeEnum::
 ::Ifc4x1::IfcActionSourceTypeEnum::Value Ifc4x1::IfcStructuralLoadGroup::ActionSource() const {  return ::Ifc4x1::IfcActionSourceTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x1::IfcStructuralLoadGroup::setActionSource(::Ifc4x1::IfcActionSourceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcActionSourceTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadGroup::Coefficient() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x1::IfcStructuralLoadGroup::Purpose() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 ::Ifc4x1::IfcStructuralResultGroup::list::ptr Ifc4x1::IfcStructuralLoadGroup::SourceOfResultGroup() const { return data_->getInverse(IFC4X1_IfcStructuralResultGroup_type, 6)->as<IfcStructuralResultGroup>(); }
 ::Ifc4x1::IfcStructuralAnalysisModel::list::ptr Ifc4x1::IfcStructuralLoadGroup::LoadGroupFor() const { return data_->getInverse(IFC4X1_IfcStructuralAnalysisModel_type, 7)->as<IfcStructuralAnalysisModel>(); }
@@ -19193,17 +19193,17 @@ Ifc4x1::IfcStructuralLoadGroup::IfcStructuralLoadGroup(std::string v1_GlobalId,
 
 // Function implementations for IfcStructuralLoadLinearForce
 boost::optional< double > Ifc4x1::IfcStructuralLoadLinearForce::LinearForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadLinearForce::LinearForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadLinearForce::LinearForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadLinearForce::LinearMomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadLinearForce::LinearMomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadLinearForce::LinearMomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralLoadLinearForce::declaration() const { return *IFC4X1_IfcStructuralLoadLinearForce_type; }
@@ -19221,11 +19221,11 @@ Ifc4x1::IfcStructuralLoadOrResult::IfcStructuralLoadOrResult(boost::optional< st
 
 // Function implementations for IfcStructuralLoadPlanarForce
 boost::optional< double > Ifc4x1::IfcStructuralLoadPlanarForce::PlanarForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadPlanarForce::PlanarForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadPlanarForce::PlanarForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralLoadPlanarForce::declaration() const { return *IFC4X1_IfcStructuralLoadPlanarForce_type; }
@@ -19235,17 +19235,17 @@ Ifc4x1::IfcStructuralLoadPlanarForce::IfcStructuralLoadPlanarForce(boost::option
 
 // Function implementations for IfcStructuralLoadSingleDisplacement
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleDisplacement::DisplacementX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleDisplacement::DisplacementY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleDisplacement::DisplacementZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralLoadSingleDisplacement::declaration() const { return *IFC4X1_IfcStructuralLoadSingleDisplacement_type; }
@@ -19255,7 +19255,7 @@ Ifc4x1::IfcStructuralLoadSingleDisplacement::IfcStructuralLoadSingleDisplacement
 
 // Function implementations for IfcStructuralLoadSingleDisplacementDistortion
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleDisplacementDistortion::Distortion() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralLoadSingleDisplacementDistortion::declaration() const { return *IFC4X1_IfcStructuralLoadSingleDisplacementDistortion_type; }
@@ -19265,17 +19265,17 @@ Ifc4x1::IfcStructuralLoadSingleDisplacementDistortion::IfcStructuralLoadSingleDi
 
 // Function implementations for IfcStructuralLoadSingleForce
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleForce::ForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleForce::ForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleForce::ForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleForce::MomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleForce::MomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleForce::MomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralLoadSingleForce::declaration() const { return *IFC4X1_IfcStructuralLoadSingleForce_type; }
@@ -19285,7 +19285,7 @@ Ifc4x1::IfcStructuralLoadSingleForce::IfcStructuralLoadSingleForce(boost::option
 
 // Function implementations for IfcStructuralLoadSingleForceWarping
 boost::optional< double > Ifc4x1::IfcStructuralLoadSingleForceWarping::WarpingMoment() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralLoadSingleForceWarping::declaration() const { return *IFC4X1_IfcStructuralLoadSingleForceWarping_type; }
@@ -19303,11 +19303,11 @@ Ifc4x1::IfcStructuralLoadStatic::IfcStructuralLoadStatic(boost::optional< std::s
 
 // Function implementations for IfcStructuralLoadTemperature
 boost::optional< double > Ifc4x1::IfcStructuralLoadTemperature::DeltaTConstant() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadTemperature::DeltaTY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralLoadTemperature::DeltaTZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralLoadTemperature::declaration() const { return *IFC4X1_IfcStructuralLoadTemperature_type; }
@@ -19383,7 +19383,7 @@ Ifc4x1::IfcStructuralResultGroup::IfcStructuralResultGroup(std::string v1_Global
 
 // Function implementations for IfcStructuralSurfaceAction
 boost::optional< ::Ifc4x1::IfcProjectedOrTrueLengthEnum::Value > Ifc4x1::IfcStructuralSurfaceAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x1::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x1::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x1::IfcStructuralSurfaceActivityTypeEnum::Value Ifc4x1::IfcStructuralSurfaceAction::PredefinedType() const {  return ::Ifc4x1::IfcStructuralSurfaceActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x1::IfcStructuralSurfaceAction::setPredefinedType(::Ifc4x1::IfcStructuralSurfaceActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcStructuralSurfaceActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -19405,7 +19405,7 @@ Ifc4x1::IfcStructuralSurfaceConnection::IfcStructuralSurfaceConnection(std::stri
 ::Ifc4x1::IfcStructuralSurfaceMemberTypeEnum::Value Ifc4x1::IfcStructuralSurfaceMember::PredefinedType() const {  return ::Ifc4x1::IfcStructuralSurfaceMemberTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x1::IfcStructuralSurfaceMember::setPredefinedType(::Ifc4x1::IfcStructuralSurfaceMemberTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcStructuralSurfaceMemberTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcStructuralSurfaceMember::Thickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStructuralSurfaceMember::declaration() const { return *IFC4X1_IfcStructuralSurfaceMember_type; }
@@ -19445,7 +19445,7 @@ void Ifc4x1::IfcStyledItem::setItem(::Ifc4x1::IfcRepresentationItem* v) { {IfcWr
 aggregate_of_instance::ptr Ifc4x1::IfcStyledItem::Styles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcStyledItem::setStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcStyledItem::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcStyledItem::declaration() const { return *IFC4X1_IfcStyledItem_type; }
@@ -19463,7 +19463,7 @@ Ifc4x1::IfcStyledRepresentation::IfcStyledRepresentation(::Ifc4x1::IfcRepresenta
 
 // Function implementations for IfcSubContractResource
 boost::optional< ::Ifc4x1::IfcSubContractResourceTypeEnum::Value > Ifc4x1::IfcSubContractResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSubContractResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSubContractResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x1::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSubContractResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSubContractResource::declaration() const { return *IFC4X1_IfcSubContractResource_type; }
@@ -19517,9 +19517,9 @@ Ifc4x1::IfcSurfaceCurve::IfcSurfaceCurve(::Ifc4x1::IfcCurve* v1_Curve3D, aggrega
 ::Ifc4x1::IfcCurve* Ifc4x1::IfcSurfaceCurveSweptAreaSolid::Directrix() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x1::IfcCurve>(true); }
 void Ifc4x1::IfcSurfaceCurveSweptAreaSolid::setDirectrix(::Ifc4x1::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcSurfaceCurveSweptAreaSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcSurfaceCurveSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcSurfaceCurveSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcSurfaceCurveSweptAreaSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcSurfaceCurveSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcSurfaceCurveSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x1::IfcSurface* Ifc4x1::IfcSurfaceCurveSweptAreaSolid::ReferenceSurface() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x1::IfcSurface>(true); }
 void Ifc4x1::IfcSurfaceCurveSweptAreaSolid::setReferenceSurface(::Ifc4x1::IfcSurface* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -19531,7 +19531,7 @@ Ifc4x1::IfcSurfaceCurveSweptAreaSolid::IfcSurfaceCurveSweptAreaSolid(::Ifc4x1::I
 
 // Function implementations for IfcSurfaceFeature
 boost::optional< ::Ifc4x1::IfcSurfaceFeatureTypeEnum::Value > Ifc4x1::IfcSurfaceFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSurfaceFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x1::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSurfaceFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x1::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSurfaceFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSurfaceFeature::declaration() const { return *IFC4X1_IfcSurfaceFeature_type; }
@@ -19563,11 +19563,11 @@ Ifc4x1::IfcSurfaceOfRevolution::IfcSurfaceOfRevolution(::Ifc4x1::IfcProfileDef*
 
 // Function implementations for IfcSurfaceReinforcementArea
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x1::IfcSurfaceReinforcementArea::SurfaceReinforcement1() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x1::IfcSurfaceReinforcementArea::SurfaceReinforcement2() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcSurfaceReinforcementArea::ShearReinforcement() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSurfaceReinforcementArea::declaration() const { return *IFC4X1_IfcSurfaceReinforcementArea_type; }
@@ -19605,9 +19605,9 @@ Ifc4x1::IfcSurfaceStyleLighting::IfcSurfaceStyleLighting(::Ifc4x1::IfcColourRgb*
 
 // Function implementations for IfcSurfaceStyleRefraction
 boost::optional< double > Ifc4x1::IfcSurfaceStyleRefraction::RefractionIndex() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x1::IfcSurfaceStyleRefraction::DispersionFactor() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSurfaceStyleRefraction::declaration() const { return *IFC4X1_IfcSurfaceStyleRefraction_type; }
@@ -19641,7 +19641,7 @@ Ifc4x1::IfcSurfaceStyleRendering::IfcSurfaceStyleRendering(::Ifc4x1::IfcColourRg
 ::Ifc4x1::IfcColourRgb* Ifc4x1::IfcSurfaceStyleShading::SurfaceColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x1::IfcColourRgb>(true); }
 void Ifc4x1::IfcSurfaceStyleShading::setSurfaceColour(::Ifc4x1::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x1::IfcSurfaceStyleShading::Transparency() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSurfaceStyleShading::declaration() const { return *IFC4X1_IfcSurfaceStyleShading_type; }
@@ -19665,11 +19665,11 @@ void Ifc4x1::IfcSurfaceTexture::setRepeatS(bool v) { {IfcWrite::IfcWriteArgument
 bool Ifc4x1::IfcSurfaceTexture::RepeatT() const {  bool v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcSurfaceTexture::setRepeatT(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcSurfaceTexture::Mode() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcCartesianTransformationOperator2D* Ifc4x1::IfcSurfaceTexture::TextureTransform() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x1::IfcSurfaceTexture::setTextureTransform(::Ifc4x1::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcSurfaceTexture::Parameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x1::IfcTextureCoordinate::list::ptr Ifc4x1::IfcSurfaceTexture::IsMappedBy() const { return data_->getInverse(IFC4X1_IfcTextureCoordinate_type, 0)->as<IfcTextureCoordinate>(); }
 ::Ifc4x1::IfcSurfaceStyleWithTextures::list::ptr Ifc4x1::IfcSurfaceTexture::UsedInStyles() const { return data_->getInverse(IFC4X1_IfcSurfaceStyleWithTextures_type, 0)->as<IfcSurfaceStyleWithTextures>(); }
@@ -19697,11 +19697,11 @@ void Ifc4x1::IfcSweptDiskSolid::setDirectrix(::Ifc4x1::IfcCurve* v) { {IfcWrite:
 double Ifc4x1::IfcSweptDiskSolid::Radius() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcSweptDiskSolid::setRadius(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x1::IfcSweptDiskSolid::InnerRadius() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x1::IfcSweptDiskSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcSweptDiskSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSweptDiskSolid::declaration() const { return *IFC4X1_IfcSweptDiskSolid_type; }
@@ -19711,7 +19711,7 @@ Ifc4x1::IfcSweptDiskSolid::IfcSweptDiskSolid(::Ifc4x1::IfcCurve* v1_Directrix, d
 
 // Function implementations for IfcSweptDiskSolidPolygonal
 boost::optional< double > Ifc4x1::IfcSweptDiskSolidPolygonal::FilletRadius() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSweptDiskSolidPolygonal::declaration() const { return *IFC4X1_IfcSweptDiskSolidPolygonal_type; }
@@ -19733,7 +19733,7 @@ Ifc4x1::IfcSweptSurface::IfcSweptSurface(::Ifc4x1::IfcProfileDef* v1_SweptCurve,
 
 // Function implementations for IfcSwitchingDevice
 boost::optional< ::Ifc4x1::IfcSwitchingDeviceTypeEnum::Value > Ifc4x1::IfcSwitchingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSwitchingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSwitchingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x1::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSwitchingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSwitchingDevice::declaration() const { return *IFC4X1_IfcSwitchingDevice_type; }
@@ -19762,7 +19762,7 @@ Ifc4x1::IfcSystem::IfcSystem(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory*
 
 // Function implementations for IfcSystemFurnitureElement
 boost::optional< ::Ifc4x1::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x1::IfcSystemFurnitureElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSystemFurnitureElement::declaration() const { return *IFC4X1_IfcSystemFurnitureElement_type; }
@@ -19772,7 +19772,7 @@ Ifc4x1::IfcSystemFurnitureElement::IfcSystemFurnitureElement(std::string v1_Glob
 
 // Function implementations for IfcSystemFurnitureElementType
 boost::optional< ::Ifc4x1::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x1::IfcSystemFurnitureElementType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x1::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x1::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x1::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x1::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x1::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcSystemFurnitureElementType::declaration() const { return *IFC4X1_IfcSystemFurnitureElementType_type; }
@@ -19790,15 +19790,15 @@ void Ifc4x1::IfcTShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc4x1::IfcTShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x1::IfcTShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcTShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcTShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x1::IfcTShapeProfileDef::WebEdgeRadius() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcTShapeProfileDef::WebSlope() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcTShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTShapeProfileDef::declaration() const { return *IFC4X1_IfcTShapeProfileDef_type; }
@@ -19808,11 +19808,11 @@ Ifc4x1::IfcTShapeProfileDef::IfcTShapeProfileDef(::Ifc4x1::IfcProfileTypeEnum::V
 
 // Function implementations for IfcTable
 boost::optional< std::string > Ifc4x1::IfcTable::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcTableRow >::ptr > Ifc4x1::IfcTable::Rows() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x1::IfcTableRow >(); }
-void Ifc4x1::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x1::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x1::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x1::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcTableColumn >::ptr > Ifc4x1::IfcTable::Columns() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x1::IfcTableColumn >(); }
-void Ifc4x1::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x1::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x1::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x1::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTable::declaration() const { return *IFC4X1_IfcTable_type; }
@@ -19822,11 +19822,11 @@ Ifc4x1::IfcTable::IfcTable(boost::optional< std::string > v1_Name, boost::option
 
 // Function implementations for IfcTableColumn
 boost::optional< std::string > Ifc4x1::IfcTableColumn::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTableColumn::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTableColumn::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcUnit* Ifc4x1::IfcTableColumn::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcUnit>(true); }
 void Ifc4x1::IfcTableColumn::setUnit(::Ifc4x1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x1::IfcReference* Ifc4x1::IfcTableColumn::ReferencePath() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x1::IfcReference>(true); }
@@ -19840,9 +19840,9 @@ Ifc4x1::IfcTableColumn::IfcTableColumn(boost::optional< std::string > v1_Identif
 
 // Function implementations for IfcTableRow
 boost::optional< aggregate_of_instance::ptr > Ifc4x1::IfcTableRow::RowCells() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(0); return v; }
-void Ifc4x1::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x1::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< bool > Ifc4x1::IfcTableRow::IsHeading() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTableRow::declaration() const { return *IFC4X1_IfcTableRow_type; }
@@ -19852,7 +19852,7 @@ Ifc4x1::IfcTableRow::IfcTableRow(boost::optional< aggregate_of_instance::ptr > v
 
 // Function implementations for IfcTank
 boost::optional< ::Ifc4x1::IfcTankTypeEnum::Value > Ifc4x1::IfcTank::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcTankTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcTank::setPredefinedType(boost::optional< ::Ifc4x1::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTankTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcTank::setPredefinedType(boost::optional< ::Ifc4x1::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTankTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTank::declaration() const { return *IFC4X1_IfcTank_type; }
@@ -19872,17 +19872,17 @@ Ifc4x1::IfcTankType::IfcTankType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHist
 
 // Function implementations for IfcTask
 boost::optional< std::string > Ifc4x1::IfcTask::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTask::WorkMethod() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 bool Ifc4x1::IfcTask::IsMilestone() const {  bool v = *data_->getArgument(9); return v; }
 void Ifc4x1::IfcTask::setIsMilestone(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< int > Ifc4x1::IfcTask::Priority() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } int v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x1::IfcTaskTime* Ifc4x1::IfcTask::TaskTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x1::IfcTaskTime>(true); }
 void Ifc4x1::IfcTask::setTaskTime(::Ifc4x1::IfcTaskTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x1::IfcTaskTypeEnum::Value > Ifc4x1::IfcTask::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x1::IfcTaskTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x1::IfcTask::setPredefinedType(boost::optional< ::Ifc4x1::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTaskTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x1::IfcTask::setPredefinedType(boost::optional< ::Ifc4x1::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTaskTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTask::declaration() const { return *IFC4X1_IfcTask_type; }
@@ -19892,39 +19892,39 @@ Ifc4x1::IfcTask::IfcTask(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory* v2_
 
 // Function implementations for IfcTaskTime
 boost::optional< ::Ifc4x1::IfcTaskDurationEnum::Value > Ifc4x1::IfcTaskTime::DurationType() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x1::IfcTaskDurationEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x1::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x1::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTaskDurationEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x1::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x1::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTaskDurationEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::ScheduleDuration() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::EarlyStart() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::EarlyFinish() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::LateStart() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::LateFinish() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::FreeFloat() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::TotalFloat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< bool > Ifc4x1::IfcTaskTime::IsCritical() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } bool v = *data_->getArgument(13); return v; }
-void Ifc4x1::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x1::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::StatusTime() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x1::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x1::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::ActualDuration() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x1::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x1::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::ActualStart() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } std::string v = *data_->getArgument(16); return v; }
-void Ifc4x1::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x1::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::ActualFinish() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } std::string v = *data_->getArgument(17); return v; }
-void Ifc4x1::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x1::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskTime::RemainingTime() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x1::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x1::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< double > Ifc4x1::IfcTaskTime::Completion() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } double v = *data_->getArgument(19); return v; }
-void Ifc4x1::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x1::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTaskTime::declaration() const { return *IFC4X1_IfcTaskTime_type; }
@@ -19946,7 +19946,7 @@ Ifc4x1::IfcTaskTimeRecurring::IfcTaskTimeRecurring(boost::optional< std::string
 ::Ifc4x1::IfcTaskTypeEnum::Value Ifc4x1::IfcTaskType::PredefinedType() const {  return ::Ifc4x1::IfcTaskTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x1::IfcTaskType::setPredefinedType(::Ifc4x1::IfcTaskTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcTaskTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTaskType::WorkMethod() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTaskType::declaration() const { return *IFC4X1_IfcTaskType_type; }
@@ -19956,17 +19956,17 @@ Ifc4x1::IfcTaskType::IfcTaskType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHist
 
 // Function implementations for IfcTelecomAddress
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcTelecomAddress::TelephoneNumbers() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcTelecomAddress::FacsimileNumbers() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTelecomAddress::PagerNumber() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcTelecomAddress::ElectronicMailAddresses() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTelecomAddress::WWWHomePageURL() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x1::IfcTelecomAddress::MessagingIDs() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTelecomAddress::declaration() const { return *IFC4X1_IfcTelecomAddress_type; }
@@ -19976,21 +19976,21 @@ Ifc4x1::IfcTelecomAddress::IfcTelecomAddress(boost::optional< ::Ifc4x1::IfcAddre
 
 // Function implementations for IfcTendon
 boost::optional< ::Ifc4x1::IfcTendonTypeEnum::Value > Ifc4x1::IfcTendon::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x1::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x1::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x1::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTendonTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x1::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x1::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTendonTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcTendon::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcTendon::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x1::IfcTendon::TensionForce() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x1::IfcTendon::PreStress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x1::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x1::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x1::IfcTendon::FrictionCoefficient() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x1::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x1::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x1::IfcTendon::AnchorageSlip() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x1::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x1::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x1::IfcTendon::MinCurvatureRadius() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x1::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x1::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTendon::declaration() const { return *IFC4X1_IfcTendon_type; }
@@ -20000,7 +20000,7 @@ Ifc4x1::IfcTendon::IfcTendon(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory*
 
 // Function implementations for IfcTendonAnchor
 boost::optional< ::Ifc4x1::IfcTendonAnchorTypeEnum::Value > Ifc4x1::IfcTendonAnchor::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x1::IfcTendonAnchorTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x1::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x1::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTendonAnchorTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x1::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x1::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTendonAnchorTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTendonAnchor::declaration() const { return *IFC4X1_IfcTendonAnchor_type; }
@@ -20022,11 +20022,11 @@ Ifc4x1::IfcTendonAnchorType::IfcTendonAnchorType(std::string v1_GlobalId, ::Ifc4
 ::Ifc4x1::IfcTendonTypeEnum::Value Ifc4x1::IfcTendonType::PredefinedType() const {  return ::Ifc4x1::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x1::IfcTendonType::setPredefinedType(::Ifc4x1::IfcTendonTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcTendonTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcTendonType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcTendonType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x1::IfcTendonType::SheathDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTendonType::declaration() const { return *IFC4X1_IfcTendonType_type; }
@@ -20088,7 +20088,7 @@ void Ifc4x1::IfcTextStyle::setTextStyle(::Ifc4x1::IfcTextStyleTextModel* v) { {I
 ::Ifc4x1::IfcTextFontSelect* Ifc4x1::IfcTextStyle::TextFontStyle() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcTextFontSelect>(true); }
 void Ifc4x1::IfcTextStyle::setTextFontStyle(::Ifc4x1::IfcTextFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x1::IfcTextStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTextStyle::declaration() const { return *IFC4X1_IfcTextStyle_type; }
@@ -20100,11 +20100,11 @@ Ifc4x1::IfcTextStyle::IfcTextStyle(boost::optional< std::string > v1_Name, ::Ifc
 std::vector< std::string > /*[1:?]*/ Ifc4x1::IfcTextStyleFontModel::FontFamily() const {  std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcTextStyleFontModel::setFontFamily(std::vector< std::string > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTextStyleFontModel::FontStyle() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTextStyleFontModel::FontVariant() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTextStyleFontModel::FontWeight() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x1::IfcSizeSelect* Ifc4x1::IfcTextStyleFontModel::FontSize() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x1::IfcSizeSelect>(true); }
 void Ifc4x1::IfcTextStyleFontModel::setFontSize(::Ifc4x1::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -20130,15 +20130,15 @@ Ifc4x1::IfcTextStyleForDefinedFont::IfcTextStyleForDefinedFont(::Ifc4x1::IfcColo
 ::Ifc4x1::IfcSizeSelect* Ifc4x1::IfcTextStyleTextModel::TextIndent() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x1::IfcSizeSelect>(true); }
 void Ifc4x1::IfcTextStyleTextModel::setTextIndent(::Ifc4x1::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTextStyleTextModel::TextAlign() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTextStyleTextModel::TextDecoration() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x1::IfcSizeSelect* Ifc4x1::IfcTextStyleTextModel::LetterSpacing() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcSizeSelect>(true); }
 void Ifc4x1::IfcTextStyleTextModel::setLetterSpacing(::Ifc4x1::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x1::IfcSizeSelect* Ifc4x1::IfcTextStyleTextModel::WordSpacing() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x1::IfcSizeSelect>(true); }
 void Ifc4x1::IfcTextStyleTextModel::setWordSpacing(::Ifc4x1::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTextStyleTextModel::TextTransform() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x1::IfcSizeSelect* Ifc4x1::IfcTextStyleTextModel::LineHeight() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x1::IfcSizeSelect>(true); }
 void Ifc4x1::IfcTextStyleTextModel::setLineHeight(::Ifc4x1::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -20162,7 +20162,7 @@ Ifc4x1::IfcTextureCoordinate::IfcTextureCoordinate(aggregate_of< ::Ifc4x1::IfcSu
 std::string Ifc4x1::IfcTextureCoordinateGenerator::Mode() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x1::IfcTextureCoordinateGenerator::setMode(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[1:?]*/ > Ifc4x1::IfcTextureCoordinateGenerator::Parameter() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTextureCoordinateGenerator::declaration() const { return *IFC4X1_IfcTextureCoordinateGenerator_type; }
@@ -20218,7 +20218,7 @@ Ifc4x1::IfcTimePeriod::IfcTimePeriod(std::string v1_StartTime, std::string v2_En
 std::string Ifc4x1::IfcTimeSeries::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x1::IfcTimeSeries::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTimeSeries::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 std::string Ifc4x1::IfcTimeSeries::StartTime() const {  std::string v = *data_->getArgument(2); return v; }
 void Ifc4x1::IfcTimeSeries::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::string Ifc4x1::IfcTimeSeries::EndTime() const {  std::string v = *data_->getArgument(3); return v; }
@@ -20228,7 +20228,7 @@ void Ifc4x1::IfcTimeSeries::setTimeSeriesDataType(::Ifc4x1::IfcTimeSeriesDataTyp
 ::Ifc4x1::IfcDataOriginEnum::Value Ifc4x1::IfcTimeSeries::DataOrigin() const {  return ::Ifc4x1::IfcDataOriginEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x1::IfcTimeSeries::setDataOrigin(::Ifc4x1::IfcDataOriginEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcDataOriginEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTimeSeries::UserDefinedDataOrigin() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x1::IfcUnit* Ifc4x1::IfcTimeSeries::Unit() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x1::IfcUnit>(true); }
 void Ifc4x1::IfcTimeSeries::setUnit(::Ifc4x1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 
@@ -20279,7 +20279,7 @@ Ifc4x1::IfcToroidalSurface::IfcToroidalSurface(::Ifc4x1::IfcAxis2Placement3D* v1
 
 // Function implementations for IfcTransformer
 boost::optional< ::Ifc4x1::IfcTransformerTypeEnum::Value > Ifc4x1::IfcTransformer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcTransformerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x1::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTransformerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x1::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTransformerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTransformer::declaration() const { return *IFC4X1_IfcTransformer_type; }
@@ -20299,9 +20299,9 @@ Ifc4x1::IfcTransformerType::IfcTransformerType(std::string v1_GlobalId, ::Ifc4x1
 
 // Function implementations for IfcTransitionCurveSegment2D
 boost::optional< double > Ifc4x1::IfcTransitionCurveSegment2D::StartRadius() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x1::IfcTransitionCurveSegment2D::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x1::IfcTransitionCurveSegment2D::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x1::IfcTransitionCurveSegment2D::EndRadius() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcTransitionCurveSegment2D::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcTransitionCurveSegment2D::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 bool Ifc4x1::IfcTransitionCurveSegment2D::IsStartRadiusCCW() const {  bool v = *data_->getArgument(5); return v; }
 void Ifc4x1::IfcTransitionCurveSegment2D::setIsStartRadiusCCW(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 bool Ifc4x1::IfcTransitionCurveSegment2D::IsEndRadiusCCW() const {  bool v = *data_->getArgument(6); return v; }
@@ -20317,7 +20317,7 @@ Ifc4x1::IfcTransitionCurveSegment2D::IfcTransitionCurveSegment2D(::Ifc4x1::IfcCa
 
 // Function implementations for IfcTransportElement
 boost::optional< ::Ifc4x1::IfcTransportElementTypeEnum::Value > Ifc4x1::IfcTransportElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcTransportElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcTransportElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcTransportElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTransportElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcTransportElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcTransportElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTransportElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTransportElement::declaration() const { return *IFC4X1_IfcTransportElement_type; }
@@ -20353,13 +20353,13 @@ Ifc4x1::IfcTrapeziumProfileDef::IfcTrapeziumProfileDef(::Ifc4x1::IfcProfileTypeE
 
 // Function implementations for IfcTriangulatedFaceSet
 boost::optional< std::vector< std::vector< double > > > Ifc4x1::IfcTriangulatedFaceSet::Normals() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(1); return v; }
-void Ifc4x1::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x1::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x1::IfcTriangulatedFaceSet::Closed() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x1::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x1::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::vector< std::vector< int > > Ifc4x1::IfcTriangulatedFaceSet::CoordIndex() const {  std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
 void Ifc4x1::IfcTriangulatedFaceSet::setCoordIndex(std::vector< std::vector< int > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x1::IfcTriangulatedFaceSet::PnIndex() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTriangulatedFaceSet::declaration() const { return *IFC4X1_IfcTriangulatedFaceSet_type; }
@@ -20397,7 +20397,7 @@ Ifc4x1::IfcTrimmedCurve::IfcTrimmedCurve(::Ifc4x1::IfcCurve* v1_BasisCurve, aggr
 
 // Function implementations for IfcTubeBundle
 boost::optional< ::Ifc4x1::IfcTubeBundleTypeEnum::Value > Ifc4x1::IfcTubeBundle::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcTubeBundleTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x1::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTubeBundleTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x1::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcTubeBundleTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcTubeBundle::declaration() const { return *IFC4X1_IfcTubeBundle_type; }
@@ -20417,9 +20417,9 @@ Ifc4x1::IfcTubeBundleType::IfcTubeBundleType(std::string v1_GlobalId, ::Ifc4x1::
 
 // Function implementations for IfcTypeObject
 boost::optional< std::string > Ifc4x1::IfcTypeObject::ApplicableOccurrence() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcPropertySetDefinition >::ptr > Ifc4x1::IfcTypeObject::HasPropertySets() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x1::IfcPropertySetDefinition >(); }
-void Ifc4x1::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x1::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(5,attr);} }
+void Ifc4x1::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x1::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(5,attr);} }
 
 ::Ifc4x1::IfcRelDefinesByType::list::ptr Ifc4x1::IfcTypeObject::Types() const { return data_->getInverse(IFC4X1_IfcRelDefinesByType_type, 5)->as<IfcRelDefinesByType>(); }
 
@@ -20430,11 +20430,11 @@ Ifc4x1::IfcTypeObject::IfcTypeObject(std::string v1_GlobalId, ::Ifc4x1::IfcOwner
 
 // Function implementations for IfcTypeProcess
 boost::optional< std::string > Ifc4x1::IfcTypeProcess::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTypeProcess::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTypeProcess::ProcessType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x1::IfcRelAssignsToProcess::list::ptr Ifc4x1::IfcTypeProcess::OperatesOn() const { return data_->getInverse(IFC4X1_IfcRelAssignsToProcess_type, 6)->as<IfcRelAssignsToProcess>(); }
 
@@ -20445,9 +20445,9 @@ Ifc4x1::IfcTypeProcess::IfcTypeProcess(std::string v1_GlobalId, ::Ifc4x1::IfcOwn
 
 // Function implementations for IfcTypeProduct
 boost::optional< aggregate_of< ::Ifc4x1::IfcRepresentationMap >::ptr > Ifc4x1::IfcTypeProduct::RepresentationMaps() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x1::IfcRepresentationMap >(); }
-void Ifc4x1::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x1::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x1::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x1::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTypeProduct::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x1::IfcRelAssignsToProduct::list::ptr Ifc4x1::IfcTypeProduct::ReferencedBy() const { return data_->getInverse(IFC4X1_IfcRelAssignsToProduct_type, 6)->as<IfcRelAssignsToProduct>(); }
 
@@ -20458,11 +20458,11 @@ Ifc4x1::IfcTypeProduct::IfcTypeProduct(std::string v1_GlobalId, ::Ifc4x1::IfcOwn
 
 // Function implementations for IfcTypeResource
 boost::optional< std::string > Ifc4x1::IfcTypeResource::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTypeResource::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcTypeResource::ResourceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x1::IfcRelAssignsToResource::list::ptr Ifc4x1::IfcTypeResource::ResourceOf() const { return data_->getInverse(IFC4X1_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -20481,11 +20481,11 @@ void Ifc4x1::IfcUShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc4x1::IfcUShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x1::IfcUShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcUShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcUShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x1::IfcUShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcUShapeProfileDef::declaration() const { return *IFC4X1_IfcUShapeProfileDef_type; }
@@ -20505,7 +20505,7 @@ Ifc4x1::IfcUnitAssignment::IfcUnitAssignment(aggregate_of_instance::ptr v1_Units
 
 // Function implementations for IfcUnitaryControlElement
 boost::optional< ::Ifc4x1::IfcUnitaryControlElementTypeEnum::Value > Ifc4x1::IfcUnitaryControlElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcUnitaryControlElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcUnitaryControlElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x1::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcUnitaryControlElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcUnitaryControlElement::declaration() const { return *IFC4X1_IfcUnitaryControlElement_type; }
@@ -20525,7 +20525,7 @@ Ifc4x1::IfcUnitaryControlElementType::IfcUnitaryControlElementType(std::string v
 
 // Function implementations for IfcUnitaryEquipment
 boost::optional< ::Ifc4x1::IfcUnitaryEquipmentTypeEnum::Value > Ifc4x1::IfcUnitaryEquipment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcUnitaryEquipmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x1::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcUnitaryEquipmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x1::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcUnitaryEquipmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcUnitaryEquipment::declaration() const { return *IFC4X1_IfcUnitaryEquipment_type; }
@@ -20545,7 +20545,7 @@ Ifc4x1::IfcUnitaryEquipmentType::IfcUnitaryEquipmentType(std::string v1_GlobalId
 
 // Function implementations for IfcValve
 boost::optional< ::Ifc4x1::IfcValveTypeEnum::Value > Ifc4x1::IfcValve::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcValveTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcValve::setPredefinedType(boost::optional< ::Ifc4x1::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcValveTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcValve::setPredefinedType(boost::optional< ::Ifc4x1::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcValveTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcValve::declaration() const { return *IFC4X1_IfcValve_type; }
@@ -20605,7 +20605,7 @@ Ifc4x1::IfcVertexPoint::IfcVertexPoint(::Ifc4x1::IfcPoint* v1_VertexGeometry) :
 
 // Function implementations for IfcVibrationIsolator
 boost::optional< ::Ifc4x1::IfcVibrationIsolatorTypeEnum::Value > Ifc4x1::IfcVibrationIsolator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcVibrationIsolatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x1::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcVibrationIsolatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x1::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcVibrationIsolatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcVibrationIsolator::declaration() const { return *IFC4X1_IfcVibrationIsolator_type; }
@@ -20645,7 +20645,7 @@ Ifc4x1::IfcVirtualGridIntersection::IfcVirtualGridIntersection(aggregate_of< ::I
 
 // Function implementations for IfcVoidingFeature
 boost::optional< ::Ifc4x1::IfcVoidingFeatureTypeEnum::Value > Ifc4x1::IfcVoidingFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcVoidingFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x1::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcVoidingFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x1::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcVoidingFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcVoidingFeature::declaration() const { return *IFC4X1_IfcVoidingFeature_type; }
@@ -20655,7 +20655,7 @@ Ifc4x1::IfcVoidingFeature::IfcVoidingFeature(std::string v1_GlobalId, ::Ifc4x1::
 
 // Function implementations for IfcWall
 boost::optional< ::Ifc4x1::IfcWallTypeEnum::Value > Ifc4x1::IfcWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcWall::setPredefinedType(boost::optional< ::Ifc4x1::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcWall::setPredefinedType(boost::optional< ::Ifc4x1::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcWall::declaration() const { return *IFC4X1_IfcWall_type; }
@@ -20691,7 +20691,7 @@ Ifc4x1::IfcWallType::IfcWallType(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHist
 
 // Function implementations for IfcWasteTerminal
 boost::optional< ::Ifc4x1::IfcWasteTerminalTypeEnum::Value > Ifc4x1::IfcWasteTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcWasteTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x1::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWasteTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x1::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWasteTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcWasteTerminal::declaration() const { return *IFC4X1_IfcWasteTerminal_type; }
@@ -20711,15 +20711,15 @@ Ifc4x1::IfcWasteTerminalType::IfcWasteTerminalType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcWindow
 boost::optional< double > Ifc4x1::IfcWindow::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x1::IfcWindow::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x1::IfcWindowTypeEnum::Value > Ifc4x1::IfcWindow::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x1::IfcWindowTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x1::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x1::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWindowTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x1::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x1::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWindowTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x1::IfcWindowTypePartitioningEnum::Value > Ifc4x1::IfcWindow::PartitioningType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x1::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x1::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x1::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWindowTypePartitioningEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x1::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x1::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWindowTypePartitioningEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x1::IfcWindow::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcWindow::declaration() const { return *IFC4X1_IfcWindow_type; }
@@ -20729,29 +20729,29 @@ Ifc4x1::IfcWindow::IfcWindow(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHistory*
 
 // Function implementations for IfcWindowLiningProperties
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::TransomThickness() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::MullionThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::FirstTransomOffset() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::SecondTransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::FirstMullionOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::SecondMullionOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 ::Ifc4x1::IfcShapeAspect* Ifc4x1::IfcWindowLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(12)))->as<::Ifc4x1::IfcShapeAspect>(true); }
 void Ifc4x1::IfcWindowLiningProperties::setShapeAspectStyle(::Ifc4x1::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::LiningOffset() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x1::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x1::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcWindowLiningProperties::declaration() const { return *IFC4X1_IfcWindowLiningProperties_type; }
@@ -20765,9 +20765,9 @@ void Ifc4x1::IfcWindowPanelProperties::setOperationType(::Ifc4x1::IfcWindowPanel
 ::Ifc4x1::IfcWindowPanelPositionEnum::Value Ifc4x1::IfcWindowPanelProperties::PanelPosition() const {  return ::Ifc4x1::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x1::IfcWindowPanelProperties::setPanelPosition(::Ifc4x1::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowPanelProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x1::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x1::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcWindowPanelProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x1::IfcShapeAspect* Ifc4x1::IfcWindowPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x1::IfcShapeAspect>(true); }
 void Ifc4x1::IfcWindowPanelProperties::setShapeAspectStyle(::Ifc4x1::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -20807,9 +20807,9 @@ void Ifc4x1::IfcWindowType::setPredefinedType(::Ifc4x1::IfcWindowTypeEnum::Value
 ::Ifc4x1::IfcWindowTypePartitioningEnum::Value Ifc4x1::IfcWindowType::PartitioningType() const {  return ::Ifc4x1::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x1::IfcWindowType::setPartitioningType(::Ifc4x1::IfcWindowTypePartitioningEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x1::IfcWindowTypePartitioningEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x1::IfcWindowType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x1::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x1::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x1::IfcWindowType::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcWindowType::declaration() const { return *IFC4X1_IfcWindowType_type; }
@@ -20819,11 +20819,11 @@ Ifc4x1::IfcWindowType::IfcWindowType(std::string v1_GlobalId, ::Ifc4x1::IfcOwner
 
 // Function implementations for IfcWorkCalendar
 boost::optional< aggregate_of< ::Ifc4x1::IfcWorkTime >::ptr > Ifc4x1::IfcWorkCalendar::WorkingTimes() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x1::IfcWorkTime >(); }
-void Ifc4x1::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x1::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x1::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x1::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcWorkTime >::ptr > Ifc4x1::IfcWorkCalendar::ExceptionTimes() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x1::IfcWorkTime >(); }
-void Ifc4x1::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x1::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x1::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x1::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x1::IfcWorkCalendarTypeEnum::Value > Ifc4x1::IfcWorkCalendar::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x1::IfcWorkCalendarTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x1::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x1::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWorkCalendarTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x1::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x1::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWorkCalendarTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcWorkCalendar::declaration() const { return *IFC4X1_IfcWorkCalendar_type; }
@@ -20835,17 +20835,17 @@ Ifc4x1::IfcWorkCalendar::IfcWorkCalendar(std::string v1_GlobalId, ::Ifc4x1::IfcO
 std::string Ifc4x1::IfcWorkControl::CreationDate() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x1::IfcWorkControl::setCreationDate(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x1::IfcPerson >::ptr > Ifc4x1::IfcWorkControl::Creators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x1::IfcPerson >(); }
-void Ifc4x1::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x1::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x1::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x1::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x1::IfcWorkControl::Purpose() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x1::IfcWorkControl::Duration() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x1::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x1::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x1::IfcWorkControl::TotalFloat() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x1::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x1::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 std::string Ifc4x1::IfcWorkControl::StartTime() const {  std::string v = *data_->getArgument(11); return v; }
 void Ifc4x1::IfcWorkControl::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x1::IfcWorkControl::FinishTime() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x1::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x1::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcWorkControl::declaration() const { return *IFC4X1_IfcWorkControl_type; }
@@ -20855,7 +20855,7 @@ Ifc4x1::IfcWorkControl::IfcWorkControl(std::string v1_GlobalId, ::Ifc4x1::IfcOwn
 
 // Function implementations for IfcWorkPlan
 boost::optional< ::Ifc4x1::IfcWorkPlanTypeEnum::Value > Ifc4x1::IfcWorkPlan::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x1::IfcWorkPlanTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x1::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x1::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWorkPlanTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x1::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x1::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWorkPlanTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcWorkPlan::declaration() const { return *IFC4X1_IfcWorkPlan_type; }
@@ -20865,7 +20865,7 @@ Ifc4x1::IfcWorkPlan::IfcWorkPlan(std::string v1_GlobalId, ::Ifc4x1::IfcOwnerHist
 
 // Function implementations for IfcWorkSchedule
 boost::optional< ::Ifc4x1::IfcWorkScheduleTypeEnum::Value > Ifc4x1::IfcWorkSchedule::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x1::IfcWorkScheduleTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x1::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x1::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWorkScheduleTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x1::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x1::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x1::IfcWorkScheduleTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcWorkSchedule::declaration() const { return *IFC4X1_IfcWorkSchedule_type; }
@@ -20877,9 +20877,9 @@ Ifc4x1::IfcWorkSchedule::IfcWorkSchedule(std::string v1_GlobalId, ::Ifc4x1::IfcO
 ::Ifc4x1::IfcRecurrencePattern* Ifc4x1::IfcWorkTime::RecurrencePattern() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x1::IfcRecurrencePattern>(true); }
 void Ifc4x1::IfcWorkTime::setRecurrencePattern(::Ifc4x1::IfcRecurrencePattern* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x1::IfcWorkTime::Start() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x1::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x1::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x1::IfcWorkTime::Finish() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcWorkTime::declaration() const { return *IFC4X1_IfcWorkTime_type; }
@@ -20897,9 +20897,9 @@ void Ifc4x1::IfcZShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc4x1::IfcZShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x1::IfcZShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x1::IfcZShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x1::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x1::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x1::IfcZShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x1::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x1::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcZShapeProfileDef::declaration() const { return *IFC4X1_IfcZShapeProfileDef_type; }
@@ -20909,7 +20909,7 @@ Ifc4x1::IfcZShapeProfileDef::IfcZShapeProfileDef(::Ifc4x1::IfcProfileTypeEnum::V
 
 // Function implementations for IfcZone
 boost::optional< std::string > Ifc4x1::IfcZone::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x1::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x1::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x1::IfcZone::declaration() const { return *IFC4X1_IfcZone_type; }
diff --git a/src/ifcparse/Ifc4x2.cpp b/src/ifcparse/Ifc4x2.cpp
index da2bd2f0c9..3e31975014 100644
--- a/src/ifcparse/Ifc4x2.cpp
+++ b/src/ifcparse/Ifc4x2.cpp
@@ -11635,11 +11635,11 @@ Ifc4x2::IfcWarpingMomentMeasure::operator double() const { return *data_->getArg
 
 // Function implementations for IfcActionRequest
 boost::optional< ::Ifc4x2::IfcActionRequestTypeEnum::Value > Ifc4x2::IfcActionRequest::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x2::IfcActionRequestTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x2::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x2::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcActionRequestTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x2::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x2::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcActionRequestTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcActionRequest::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcActionRequest::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcActionRequest::declaration() const { return *IFC4X2_IfcActionRequest_type; }
@@ -11662,9 +11662,9 @@ Ifc4x2::IfcActor::IfcActor(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory* v
 ::Ifc4x2::IfcRoleEnum::Value Ifc4x2::IfcActorRole::Role() const {  return ::Ifc4x2::IfcRoleEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x2::IfcActorRole::setRole(::Ifc4x2::IfcRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcRoleEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcActorRole::UserDefinedRole() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcActorRole::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x2::IfcExternalReferenceRelationship::list::ptr Ifc4x2::IfcActorRole::HasExternalReference() const { return data_->getInverse(IFC4X2_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -11675,7 +11675,7 @@ Ifc4x2::IfcActorRole::IfcActorRole(::Ifc4x2::IfcRoleEnum::Value v1_Role, boost::
 
 // Function implementations for IfcActuator
 boost::optional< ::Ifc4x2::IfcActuatorTypeEnum::Value > Ifc4x2::IfcActuator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcActuatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x2::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcActuatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x2::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcActuatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcActuator::declaration() const { return *IFC4X2_IfcActuator_type; }
@@ -11695,11 +11695,11 @@ Ifc4x2::IfcActuatorType::IfcActuatorType(std::string v1_GlobalId, ::Ifc4x2::IfcO
 
 // Function implementations for IfcAddress
 boost::optional< ::Ifc4x2::IfcAddressTypeEnum::Value > Ifc4x2::IfcAddress::Purpose() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } return ::Ifc4x2::IfcAddressTypeEnum::FromString(*data_->getArgument(0)); }
-void Ifc4x2::IfcAddress::setPurpose(boost::optional< ::Ifc4x2::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAddressTypeEnum::ToString(*v)));data_->setArgument(0,attr);} }
+void Ifc4x2::IfcAddress::setPurpose(boost::optional< ::Ifc4x2::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAddressTypeEnum::ToString(*v)));}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAddress::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAddress::UserDefinedPurpose() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x2::IfcPerson::list::ptr Ifc4x2::IfcAddress::OfPerson() const { return data_->getInverse(IFC4X2_IfcPerson_type, 7)->as<IfcPerson>(); }
 ::Ifc4x2::IfcOrganization::list::ptr Ifc4x2::IfcAddress::OfOrganization() const { return data_->getInverse(IFC4X2_IfcOrganization_type, 4)->as<IfcOrganization>(); }
@@ -11737,7 +11737,7 @@ Ifc4x2::IfcAdvancedFace::IfcAdvancedFace(aggregate_of< ::Ifc4x2::IfcFaceBound >:
 
 // Function implementations for IfcAirTerminal
 boost::optional< ::Ifc4x2::IfcAirTerminalTypeEnum::Value > Ifc4x2::IfcAirTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcAirTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x2::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAirTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x2::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAirTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcAirTerminal::declaration() const { return *IFC4X2_IfcAirTerminal_type; }
@@ -11747,7 +11747,7 @@ Ifc4x2::IfcAirTerminal::IfcAirTerminal(std::string v1_GlobalId, ::Ifc4x2::IfcOwn
 
 // Function implementations for IfcAirTerminalBox
 boost::optional< ::Ifc4x2::IfcAirTerminalBoxTypeEnum::Value > Ifc4x2::IfcAirTerminalBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcAirTerminalBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x2::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAirTerminalBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x2::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAirTerminalBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcAirTerminalBox::declaration() const { return *IFC4X2_IfcAirTerminalBox_type; }
@@ -11777,7 +11777,7 @@ Ifc4x2::IfcAirTerminalType::IfcAirTerminalType(std::string v1_GlobalId, ::Ifc4x2
 
 // Function implementations for IfcAirToAirHeatRecovery
 boost::optional< ::Ifc4x2::IfcAirToAirHeatRecoveryTypeEnum::Value > Ifc4x2::IfcAirToAirHeatRecovery::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcAirToAirHeatRecoveryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x2::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x2::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcAirToAirHeatRecovery::declaration() const { return *IFC4X2_IfcAirToAirHeatRecovery_type; }
@@ -11797,7 +11797,7 @@ Ifc4x2::IfcAirToAirHeatRecoveryType::IfcAirToAirHeatRecoveryType(std::string v1_
 
 // Function implementations for IfcAlarm
 boost::optional< ::Ifc4x2::IfcAlarmTypeEnum::Value > Ifc4x2::IfcAlarm::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcAlarmTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x2::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAlarmTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x2::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAlarmTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcAlarm::declaration() const { return *IFC4X2_IfcAlarm_type; }
@@ -11817,7 +11817,7 @@ Ifc4x2::IfcAlarmType::IfcAlarmType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHi
 
 // Function implementations for IfcAlignment
 boost::optional< ::Ifc4x2::IfcAlignmentTypeEnum::Value > Ifc4x2::IfcAlignment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcAlignmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x2::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAlignmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x2::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAlignmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcAlignment::declaration() const { return *IFC4X2_IfcAlignment_type; }
@@ -11827,7 +11827,7 @@ Ifc4x2::IfcAlignment::IfcAlignment(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHi
 
 // Function implementations for IfcAlignment2DHorizontal
 boost::optional< double > Ifc4x2::IfcAlignment2DHorizontal::StartDistAlong() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcAlignment2DHorizontal::setStartDistAlong(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcAlignment2DHorizontal::setStartDistAlong(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc4x2::IfcAlignment2DHorizontalSegment >::ptr Ifc4x2::IfcAlignment2DHorizontal::Segments() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x2::IfcAlignment2DHorizontalSegment >(); }
 void Ifc4x2::IfcAlignment2DHorizontal::setSegments(aggregate_of< ::Ifc4x2::IfcAlignment2DHorizontalSegment >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -11851,11 +11851,11 @@ Ifc4x2::IfcAlignment2DHorizontalSegment::IfcAlignment2DHorizontalSegment(boost::
 
 // Function implementations for IfcAlignment2DSegment
 boost::optional< bool > Ifc4x2::IfcAlignment2DSegment::TangentialContinuity() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } bool v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcAlignment2DSegment::setTangentialContinuity(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcAlignment2DSegment::setTangentialContinuity(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAlignment2DSegment::StartTag() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcAlignment2DSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcAlignment2DSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAlignment2DSegment::EndTag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcAlignment2DSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcAlignment2DSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcAlignment2DSegment::declaration() const { return *IFC4X2_IfcAlignment2DSegment_type; }
@@ -11929,7 +11929,7 @@ void Ifc4x2::IfcAlignmentCurve::setHorizontal(::Ifc4x2::IfcAlignment2DHorizontal
 ::Ifc4x2::IfcAlignment2DVertical* Ifc4x2::IfcAlignmentCurve::Vertical() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x2::IfcAlignment2DVertical>(true); }
 void Ifc4x2::IfcAlignmentCurve::setVertical(::Ifc4x2::IfcAlignment2DVertical* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAlignmentCurve::Tag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcAlignmentCurve::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcAlignmentCurve::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcAlignmentCurve::declaration() const { return *IFC4X2_IfcAlignmentCurve_type; }
@@ -11950,7 +11950,7 @@ Ifc4x2::IfcAnnotation::IfcAnnotation(std::string v1_GlobalId, ::Ifc4x2::IfcOwner
 ::Ifc4x2::IfcCurve* Ifc4x2::IfcAnnotationFillArea::OuterBoundary() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x2::IfcCurve>(true); }
 void Ifc4x2::IfcAnnotationFillArea::setOuterBoundary(::Ifc4x2::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcCurve >::ptr > Ifc4x2::IfcAnnotationFillArea::InnerBoundaries() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x2::IfcCurve >(); }
-void Ifc4x2::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x2::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x2::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x2::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcAnnotationFillArea::declaration() const { return *IFC4X2_IfcAnnotationFillArea_type; }
@@ -11976,25 +11976,25 @@ Ifc4x2::IfcApplication::IfcApplication(::Ifc4x2::IfcOrganization* v1_Application
 
 // Function implementations for IfcAppliedValue
 boost::optional< std::string > Ifc4x2::IfcAppliedValue::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAppliedValue::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x2::IfcAppliedValueSelect* Ifc4x2::IfcAppliedValue::AppliedValue() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x2::IfcAppliedValueSelect>(true); }
 void Ifc4x2::IfcAppliedValue::setAppliedValue(::Ifc4x2::IfcAppliedValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcMeasureWithUnit* Ifc4x2::IfcAppliedValue::UnitBasis() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcMeasureWithUnit>(true); }
 void Ifc4x2::IfcAppliedValue::setUnitBasis(::Ifc4x2::IfcMeasureWithUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAppliedValue::ApplicableDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAppliedValue::FixedUntilDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAppliedValue::Category() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAppliedValue::Condition() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x2::IfcArithmeticOperatorEnum::Value > Ifc4x2::IfcAppliedValue::ArithmeticOperator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcArithmeticOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x2::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcArithmeticOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x2::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcArithmeticOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcAppliedValue >::ptr > Ifc4x2::IfcAppliedValue::Components() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x2::IfcAppliedValue >(); }
-void Ifc4x2::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x2::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 
 ::Ifc4x2::IfcExternalReferenceRelationship::list::ptr Ifc4x2::IfcAppliedValue::HasExternalReference() const { return data_->getInverse(IFC4X2_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -12005,19 +12005,19 @@ Ifc4x2::IfcAppliedValue::IfcAppliedValue(boost::optional< std::string > v1_Name,
 
 // Function implementations for IfcApproval
 boost::optional< std::string > Ifc4x2::IfcApproval::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcApproval::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcApproval::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x2::IfcApproval::TimeOfApproval() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcApproval::Status() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcApproval::Level() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcApproval::Qualifier() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x2::IfcActorSelect* Ifc4x2::IfcApproval::RequestingApproval() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x2::IfcActorSelect>(true); }
 void Ifc4x2::IfcApproval::setRequestingApproval(::Ifc4x2::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x2::IfcActorSelect* Ifc4x2::IfcApproval::GivingApproval() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x2::IfcActorSelect>(true); }
@@ -12078,7 +12078,7 @@ Ifc4x2::IfcArbitraryProfileDefWithVoids::IfcArbitraryProfileDefWithVoids(::Ifc4x
 
 // Function implementations for IfcAsset
 boost::optional< std::string > Ifc4x2::IfcAsset::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x2::IfcCostValue* Ifc4x2::IfcAsset::OriginalValue() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcCostValue>(true); }
 void Ifc4x2::IfcAsset::setOriginalValue(::Ifc4x2::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 ::Ifc4x2::IfcCostValue* Ifc4x2::IfcAsset::CurrentValue() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x2::IfcCostValue>(true); }
@@ -12092,7 +12092,7 @@ void Ifc4x2::IfcAsset::setUser(::Ifc4x2::IfcActorSelect* v) { {IfcWrite::IfcWrit
 ::Ifc4x2::IfcPerson* Ifc4x2::IfcAsset::ResponsiblePerson() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x2::IfcPerson>(true); }
 void Ifc4x2::IfcAsset::setResponsiblePerson(::Ifc4x2::IfcPerson* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x2::IfcAsset::IncorporationDate() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x2::IfcCostValue* Ifc4x2::IfcAsset::DepreciatedValue() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x2::IfcCostValue>(true); }
 void Ifc4x2::IfcAsset::setDepreciatedValue(::Ifc4x2::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -12112,21 +12112,21 @@ void Ifc4x2::IfcAsymmetricIShapeProfileDef::setWebThickness(double v) { {IfcWrit
 double Ifc4x2::IfcAsymmetricIShapeProfileDef::BottomFlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x2::IfcAsymmetricIShapeProfileDef::setBottomFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcAsymmetricIShapeProfileDef::BottomFlangeFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 double Ifc4x2::IfcAsymmetricIShapeProfileDef::TopFlangeWidth() const {  double v = *data_->getArgument(8); return v; }
 void Ifc4x2::IfcAsymmetricIShapeProfileDef::setTopFlangeWidth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x2::IfcAsymmetricIShapeProfileDef::TopFlangeThickness() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcAsymmetricIShapeProfileDef::TopFlangeFilletRadius() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcAsymmetricIShapeProfileDef::BottomFlangeEdgeRadius() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x2::IfcAsymmetricIShapeProfileDef::BottomFlangeSlope() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x2::IfcAsymmetricIShapeProfileDef::TopFlangeEdgeRadius() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x2::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x2::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x2::IfcAsymmetricIShapeProfileDef::TopFlangeSlope() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x2::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x2::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcAsymmetricIShapeProfileDef::declaration() const { return *IFC4X2_IfcAsymmetricIShapeProfileDef_type; }
@@ -12136,7 +12136,7 @@ Ifc4x2::IfcAsymmetricIShapeProfileDef::IfcAsymmetricIShapeProfileDef(::Ifc4x2::I
 
 // Function implementations for IfcAudioVisualAppliance
 boost::optional< ::Ifc4x2::IfcAudioVisualApplianceTypeEnum::Value > Ifc4x2::IfcAudioVisualAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcAudioVisualApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x2::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAudioVisualApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x2::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAudioVisualApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcAudioVisualAppliance::declaration() const { return *IFC4X2_IfcAudioVisualAppliance_type; }
@@ -12260,7 +12260,7 @@ Ifc4x2::IfcBSplineSurfaceWithKnots::IfcBSplineSurfaceWithKnots(int v1_UDegree, i
 
 // Function implementations for IfcBeam
 boost::optional< ::Ifc4x2::IfcBeamTypeEnum::Value > Ifc4x2::IfcBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x2::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x2::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBeam::declaration() const { return *IFC4X2_IfcBeam_type; }
@@ -12288,7 +12288,7 @@ Ifc4x2::IfcBeamType::IfcBeamType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHist
 
 // Function implementations for IfcBearing
 boost::optional< ::Ifc4x2::IfcBearingTypeEnum::Value > Ifc4x2::IfcBearing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcBearingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcBearing::setPredefinedType(boost::optional< ::Ifc4x2::IfcBearingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBearingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcBearing::setPredefinedType(boost::optional< ::Ifc4x2::IfcBearingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBearingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBearing::declaration() const { return *IFC4X2_IfcBearing_type; }
@@ -12334,7 +12334,7 @@ Ifc4x2::IfcBlock::IfcBlock(::Ifc4x2::IfcAxis2Placement3D* v1_Position, double v2
 
 // Function implementations for IfcBoiler
 boost::optional< ::Ifc4x2::IfcBoilerTypeEnum::Value > Ifc4x2::IfcBoiler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcBoilerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x2::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBoilerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x2::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBoilerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBoiler::declaration() const { return *IFC4X2_IfcBoiler_type; }
@@ -12376,7 +12376,7 @@ Ifc4x2::IfcBooleanResult::IfcBooleanResult(::Ifc4x2::IfcBooleanOperator::Value v
 
 // Function implementations for IfcBoundaryCondition
 boost::optional< std::string > Ifc4x2::IfcBoundaryCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBoundaryCondition::declaration() const { return *IFC4X2_IfcBoundaryCondition_type; }
@@ -12501,7 +12501,7 @@ Ifc4x2::IfcBoxedHalfSpace::IfcBoxedHalfSpace(::Ifc4x2::IfcSurface* v1_BaseSurfac
 
 // Function implementations for IfcBridge
 boost::optional< ::Ifc4x2::IfcBridgeTypeEnum::Value > Ifc4x2::IfcBridge::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x2::IfcBridgeTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x2::IfcBridge::setPredefinedType(boost::optional< ::Ifc4x2::IfcBridgeTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBridgeTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x2::IfcBridge::setPredefinedType(boost::optional< ::Ifc4x2::IfcBridgeTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBridgeTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBridge::declaration() const { return *IFC4X2_IfcBridge_type; }
@@ -12511,7 +12511,7 @@ Ifc4x2::IfcBridge::IfcBridge(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory*
 
 // Function implementations for IfcBridgePart
 boost::optional< ::Ifc4x2::IfcBridgePartTypeEnum::Value > Ifc4x2::IfcBridgePart::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x2::IfcBridgePartTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x2::IfcBridgePart::setPredefinedType(boost::optional< ::Ifc4x2::IfcBridgePartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBridgePartTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x2::IfcBridgePart::setPredefinedType(boost::optional< ::Ifc4x2::IfcBridgePartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBridgePartTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBridgePart::declaration() const { return *IFC4X2_IfcBridgePart_type; }
@@ -12521,9 +12521,9 @@ Ifc4x2::IfcBridgePart::IfcBridgePart(std::string v1_GlobalId, ::Ifc4x2::IfcOwner
 
 // Function implementations for IfcBuilding
 boost::optional< double > Ifc4x2::IfcBuilding::ElevationOfRefHeight() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcBuilding::ElevationOfTerrain() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x2::IfcPostalAddress* Ifc4x2::IfcBuilding::BuildingAddress() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x2::IfcPostalAddress>(true); }
 void Ifc4x2::IfcBuilding::setBuildingAddress(::Ifc4x2::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 
@@ -12543,7 +12543,7 @@ Ifc4x2::IfcBuildingElement::IfcBuildingElement(std::string v1_GlobalId, ::Ifc4x2
 
 // Function implementations for IfcBuildingElementPart
 boost::optional< ::Ifc4x2::IfcBuildingElementPartTypeEnum::Value > Ifc4x2::IfcBuildingElementPart::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcBuildingElementPartTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x2::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBuildingElementPartTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x2::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBuildingElementPartTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBuildingElementPart::declaration() const { return *IFC4X2_IfcBuildingElementPart_type; }
@@ -12563,7 +12563,7 @@ Ifc4x2::IfcBuildingElementPartType::IfcBuildingElementPartType(std::string v1_Gl
 
 // Function implementations for IfcBuildingElementProxy
 boost::optional< ::Ifc4x2::IfcBuildingElementProxyTypeEnum::Value > Ifc4x2::IfcBuildingElementProxy::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcBuildingElementProxyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x2::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBuildingElementProxyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x2::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBuildingElementProxyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBuildingElementProxy::declaration() const { return *IFC4X2_IfcBuildingElementProxy_type; }
@@ -12591,7 +12591,7 @@ Ifc4x2::IfcBuildingElementType::IfcBuildingElementType(std::string v1_GlobalId,
 
 // Function implementations for IfcBuildingStorey
 boost::optional< double > Ifc4x2::IfcBuildingStorey::Elevation() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBuildingStorey::declaration() const { return *IFC4X2_IfcBuildingStorey_type; }
@@ -12601,9 +12601,9 @@ Ifc4x2::IfcBuildingStorey::IfcBuildingStorey(std::string v1_GlobalId, ::Ifc4x2::
 
 // Function implementations for IfcBuildingSystem
 boost::optional< ::Ifc4x2::IfcBuildingSystemTypeEnum::Value > Ifc4x2::IfcBuildingSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x2::IfcBuildingSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x2::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x2::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBuildingSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x2::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x2::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBuildingSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcBuildingSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBuildingSystem::declaration() const { return *IFC4X2_IfcBuildingSystem_type; }
@@ -12613,7 +12613,7 @@ Ifc4x2::IfcBuildingSystem::IfcBuildingSystem(std::string v1_GlobalId, ::Ifc4x2::
 
 // Function implementations for IfcBurner
 boost::optional< ::Ifc4x2::IfcBurnerTypeEnum::Value > Ifc4x2::IfcBurner::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcBurnerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x2::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBurnerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x2::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcBurnerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcBurner::declaration() const { return *IFC4X2_IfcBurner_type; }
@@ -12641,7 +12641,7 @@ void Ifc4x2::IfcCShapeProfileDef::setWallThickness(double v) { {IfcWrite::IfcWri
 double Ifc4x2::IfcCShapeProfileDef::Girth() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x2::IfcCShapeProfileDef::setGirth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcCShapeProfileDef::InternalFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCShapeProfileDef::declaration() const { return *IFC4X2_IfcCShapeProfileDef_type; }
@@ -12651,7 +12651,7 @@ Ifc4x2::IfcCShapeProfileDef::IfcCShapeProfileDef(::Ifc4x2::IfcProfileTypeEnum::V
 
 // Function implementations for IfcCableCarrierFitting
 boost::optional< ::Ifc4x2::IfcCableCarrierFittingTypeEnum::Value > Ifc4x2::IfcCableCarrierFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCableCarrierFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x2::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCableCarrierFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x2::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCableCarrierFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCableCarrierFitting::declaration() const { return *IFC4X2_IfcCableCarrierFitting_type; }
@@ -12671,7 +12671,7 @@ Ifc4x2::IfcCableCarrierFittingType::IfcCableCarrierFittingType(std::string v1_Gl
 
 // Function implementations for IfcCableCarrierSegment
 boost::optional< ::Ifc4x2::IfcCableCarrierSegmentTypeEnum::Value > Ifc4x2::IfcCableCarrierSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCableCarrierSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x2::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCableCarrierSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x2::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCableCarrierSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCableCarrierSegment::declaration() const { return *IFC4X2_IfcCableCarrierSegment_type; }
@@ -12691,7 +12691,7 @@ Ifc4x2::IfcCableCarrierSegmentType::IfcCableCarrierSegmentType(std::string v1_Gl
 
 // Function implementations for IfcCableFitting
 boost::optional< ::Ifc4x2::IfcCableFittingTypeEnum::Value > Ifc4x2::IfcCableFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCableFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x2::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCableFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x2::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCableFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCableFitting::declaration() const { return *IFC4X2_IfcCableFitting_type; }
@@ -12711,7 +12711,7 @@ Ifc4x2::IfcCableFittingType::IfcCableFittingType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCableSegment
 boost::optional< ::Ifc4x2::IfcCableSegmentTypeEnum::Value > Ifc4x2::IfcCableSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCableSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x2::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCableSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x2::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCableSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCableSegment::declaration() const { return *IFC4X2_IfcCableSegment_type; }
@@ -12731,7 +12731,7 @@ Ifc4x2::IfcCableSegmentType::IfcCableSegmentType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCaissonFoundation
 boost::optional< ::Ifc4x2::IfcCaissonFoundationTypeEnum::Value > Ifc4x2::IfcCaissonFoundation::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCaissonFoundationTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCaissonFoundation::setPredefinedType(boost::optional< ::Ifc4x2::IfcCaissonFoundationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCaissonFoundationTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCaissonFoundation::setPredefinedType(boost::optional< ::Ifc4x2::IfcCaissonFoundationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCaissonFoundationTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCaissonFoundation::declaration() const { return *IFC4X2_IfcCaissonFoundation_type; }
@@ -12771,7 +12771,7 @@ Ifc4x2::IfcCartesianPointList::IfcCartesianPointList() : IfcGeometricRepresentat
 std::vector< std::vector< double > > Ifc4x2::IfcCartesianPointList2D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcCartesianPointList2D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcCartesianPointList2D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCartesianPointList2D::declaration() const { return *IFC4X2_IfcCartesianPointList2D_type; }
@@ -12783,7 +12783,7 @@ Ifc4x2::IfcCartesianPointList2D::IfcCartesianPointList2D(std::vector< std::vecto
 std::vector< std::vector< double > > Ifc4x2::IfcCartesianPointList3D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcCartesianPointList3D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcCartesianPointList3D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCartesianPointList3D::declaration() const { return *IFC4X2_IfcCartesianPointList3D_type; }
@@ -12799,7 +12799,7 @@ void Ifc4x2::IfcCartesianTransformationOperator::setAxis2(::Ifc4x2::IfcDirection
 ::Ifc4x2::IfcCartesianPoint* Ifc4x2::IfcCartesianTransformationOperator::LocalOrigin() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x2::IfcCartesianPoint>(true); }
 void Ifc4x2::IfcCartesianTransformationOperator::setLocalOrigin(::Ifc4x2::IfcCartesianPoint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcCartesianTransformationOperator::Scale() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCartesianTransformationOperator::declaration() const { return *IFC4X2_IfcCartesianTransformationOperator_type; }
@@ -12817,7 +12817,7 @@ Ifc4x2::IfcCartesianTransformationOperator2D::IfcCartesianTransformationOperator
 
 // Function implementations for IfcCartesianTransformationOperator2DnonUniform
 boost::optional< double > Ifc4x2::IfcCartesianTransformationOperator2DnonUniform::Scale2() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCartesianTransformationOperator2DnonUniform::declaration() const { return *IFC4X2_IfcCartesianTransformationOperator2DnonUniform_type; }
@@ -12837,9 +12837,9 @@ Ifc4x2::IfcCartesianTransformationOperator3D::IfcCartesianTransformationOperator
 
 // Function implementations for IfcCartesianTransformationOperator3DnonUniform
 boost::optional< double > Ifc4x2::IfcCartesianTransformationOperator3DnonUniform::Scale2() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcCartesianTransformationOperator3DnonUniform::Scale3() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCartesianTransformationOperator3DnonUniform::declaration() const { return *IFC4X2_IfcCartesianTransformationOperator3DnonUniform_type; }
@@ -12859,7 +12859,7 @@ Ifc4x2::IfcCenterLineProfileDef::IfcCenterLineProfileDef(::Ifc4x2::IfcProfileTyp
 
 // Function implementations for IfcChiller
 boost::optional< ::Ifc4x2::IfcChillerTypeEnum::Value > Ifc4x2::IfcChiller::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcChillerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x2::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcChillerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x2::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcChillerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcChiller::declaration() const { return *IFC4X2_IfcChiller_type; }
@@ -12879,7 +12879,7 @@ Ifc4x2::IfcChillerType::IfcChillerType(std::string v1_GlobalId, ::Ifc4x2::IfcOwn
 
 // Function implementations for IfcChimney
 boost::optional< ::Ifc4x2::IfcChimneyTypeEnum::Value > Ifc4x2::IfcChimney::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcChimneyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x2::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcChimneyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x2::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcChimneyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcChimney::declaration() const { return *IFC4X2_IfcChimney_type; }
@@ -12957,19 +12957,19 @@ Ifc4x2::IfcCivilElementType::IfcCivilElementType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcClassification
 boost::optional< std::string > Ifc4x2::IfcClassification::Source() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcClassification::Edition() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcClassification::EditionDate() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::string Ifc4x2::IfcClassification::Name() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcClassification::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcClassification::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcClassification::Location() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcClassification::ReferenceTokens() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x2::IfcRelAssociatesClassification::list::ptr Ifc4x2::IfcClassification::ClassificationForObjects() const { return data_->getInverse(IFC4X2_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x2::IfcClassificationReference::list::ptr Ifc4x2::IfcClassification::HasReferences() const { return data_->getInverse(IFC4X2_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -12983,9 +12983,9 @@ Ifc4x2::IfcClassification::IfcClassification(boost::optional< std::string > v1_S
 ::Ifc4x2::IfcClassificationReferenceSelect* Ifc4x2::IfcClassificationReference::ReferencedSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcClassificationReferenceSelect>(true); }
 void Ifc4x2::IfcClassificationReference::setReferencedSource(::Ifc4x2::IfcClassificationReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcClassificationReference::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcClassificationReference::Sort() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x2::IfcRelAssociatesClassification::list::ptr Ifc4x2::IfcClassificationReference::ClassificationRefForObjects() const { return data_->getInverse(IFC4X2_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x2::IfcClassificationReference::list::ptr Ifc4x2::IfcClassificationReference::HasReferences() const { return data_->getInverse(IFC4X2_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -13005,7 +13005,7 @@ Ifc4x2::IfcClosedShell::IfcClosedShell(aggregate_of< ::Ifc4x2::IfcFace >::ptr v1
 
 // Function implementations for IfcCoil
 boost::optional< ::Ifc4x2::IfcCoilTypeEnum::Value > Ifc4x2::IfcCoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x2::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x2::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCoil::declaration() const { return *IFC4X2_IfcCoil_type; }
@@ -13049,7 +13049,7 @@ Ifc4x2::IfcColourRgbList::IfcColourRgbList(std::vector< std::vector< double > >
 
 // Function implementations for IfcColourSpecification
 boost::optional< std::string > Ifc4x2::IfcColourSpecification::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcColourSpecification::declaration() const { return *IFC4X2_IfcColourSpecification_type; }
@@ -13059,7 +13059,7 @@ Ifc4x2::IfcColourSpecification::IfcColourSpecification(boost::optional< std::str
 
 // Function implementations for IfcColumn
 boost::optional< ::Ifc4x2::IfcColumnTypeEnum::Value > Ifc4x2::IfcColumn::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcColumnTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x2::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcColumnTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x2::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcColumnTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcColumn::declaration() const { return *IFC4X2_IfcColumn_type; }
@@ -13087,7 +13087,7 @@ Ifc4x2::IfcColumnType::IfcColumnType(std::string v1_GlobalId, ::Ifc4x2::IfcOwner
 
 // Function implementations for IfcCommunicationsAppliance
 boost::optional< ::Ifc4x2::IfcCommunicationsApplianceTypeEnum::Value > Ifc4x2::IfcCommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x2::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x2::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCommunicationsAppliance::declaration() const { return *IFC4X2_IfcCommunicationsAppliance_type; }
@@ -13119,11 +13119,11 @@ Ifc4x2::IfcComplexProperty::IfcComplexProperty(std::string v1_Name, boost::optio
 
 // Function implementations for IfcComplexPropertyTemplate
 boost::optional< std::string > Ifc4x2::IfcComplexPropertyTemplate::UsageName() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x2::IfcComplexPropertyTemplateTypeEnum::Value > Ifc4x2::IfcComplexPropertyTemplate::TemplateType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x2::IfcComplexPropertyTemplateTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x2::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x2::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x2::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x2::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcPropertyTemplate >::ptr > Ifc4x2::IfcComplexPropertyTemplate::HasPropertyTemplates() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x2::IfcPropertyTemplate >(); }
-void Ifc4x2::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x2::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x2::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x2::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcComplexPropertyTemplate::declaration() const { return *IFC4X2_IfcComplexPropertyTemplate_type; }
@@ -13170,7 +13170,7 @@ Ifc4x2::IfcCompositeCurveSegment::IfcCompositeCurveSegment(::Ifc4x2::IfcTransiti
 aggregate_of< ::Ifc4x2::IfcProfileDef >::ptr Ifc4x2::IfcCompositeProfileDef::Profiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x2::IfcProfileDef >(); }
 void Ifc4x2::IfcCompositeProfileDef::setProfiles(aggregate_of< ::Ifc4x2::IfcProfileDef >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x2::IfcCompositeProfileDef::Label() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCompositeProfileDef::declaration() const { return *IFC4X2_IfcCompositeProfileDef_type; }
@@ -13180,7 +13180,7 @@ Ifc4x2::IfcCompositeProfileDef::IfcCompositeProfileDef(::Ifc4x2::IfcProfileTypeE
 
 // Function implementations for IfcCompressor
 boost::optional< ::Ifc4x2::IfcCompressorTypeEnum::Value > Ifc4x2::IfcCompressor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCompressorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x2::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCompressorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x2::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCompressorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCompressor::declaration() const { return *IFC4X2_IfcCompressor_type; }
@@ -13200,7 +13200,7 @@ Ifc4x2::IfcCompressorType::IfcCompressorType(std::string v1_GlobalId, ::Ifc4x2::
 
 // Function implementations for IfcCondenser
 boost::optional< ::Ifc4x2::IfcCondenserTypeEnum::Value > Ifc4x2::IfcCondenser::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCondenserTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x2::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCondenserTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x2::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCondenserTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCondenser::declaration() const { return *IFC4X2_IfcCondenser_type; }
@@ -13260,11 +13260,11 @@ Ifc4x2::IfcConnectionGeometry::IfcConnectionGeometry() : IfcUtil::IfcBaseEntity(
 
 // Function implementations for IfcConnectionPointEccentricity
 boost::optional< double > Ifc4x2::IfcConnectionPointEccentricity::EccentricityInX() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcConnectionPointEccentricity::EccentricityInY() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcConnectionPointEccentricity::EccentricityInZ() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcConnectionPointEccentricity::declaration() const { return *IFC4X2_IfcConnectionPointEccentricity_type; }
@@ -13312,17 +13312,17 @@ Ifc4x2::IfcConnectionVolumeGeometry::IfcConnectionVolumeGeometry(::Ifc4x2::IfcSo
 std::string Ifc4x2::IfcConstraint::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcConstraint::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcConstraint::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x2::IfcConstraintEnum::Value Ifc4x2::IfcConstraint::ConstraintGrade() const {  return ::Ifc4x2::IfcConstraintEnum::FromString(*data_->getArgument(2)); }
 void Ifc4x2::IfcConstraint::setConstraintGrade(::Ifc4x2::IfcConstraintEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcConstraintEnum::ToString(v)));data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x2::IfcConstraint::ConstraintSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x2::IfcActorSelect* Ifc4x2::IfcConstraint::CreatingActor() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x2::IfcActorSelect>(true); }
 void Ifc4x2::IfcConstraint::setCreatingActor(::Ifc4x2::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcConstraint::CreationTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcConstraint::UserDefinedGrade() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x2::IfcExternalReferenceRelationship::list::ptr Ifc4x2::IfcConstraint::HasExternalReferences() const { return data_->getInverse(IFC4X2_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x2::IfcResourceConstraintRelationship::list::ptr Ifc4x2::IfcConstraint::PropertiesForConstraint() const { return data_->getInverse(IFC4X2_IfcResourceConstraintRelationship_type, 2)->as<IfcResourceConstraintRelationship>(); }
@@ -13334,7 +13334,7 @@ Ifc4x2::IfcConstraint::IfcConstraint(std::string v1_Name, boost::optional< std::
 
 // Function implementations for IfcConstructionEquipmentResource
 boost::optional< ::Ifc4x2::IfcConstructionEquipmentResourceTypeEnum::Value > Ifc4x2::IfcConstructionEquipmentResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcConstructionEquipmentResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcConstructionEquipmentResource::declaration() const { return *IFC4X2_IfcConstructionEquipmentResource_type; }
@@ -13354,7 +13354,7 @@ Ifc4x2::IfcConstructionEquipmentResourceType::IfcConstructionEquipmentResourceTy
 
 // Function implementations for IfcConstructionMaterialResource
 boost::optional< ::Ifc4x2::IfcConstructionMaterialResourceTypeEnum::Value > Ifc4x2::IfcConstructionMaterialResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcConstructionMaterialResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcConstructionMaterialResource::declaration() const { return *IFC4X2_IfcConstructionMaterialResource_type; }
@@ -13374,7 +13374,7 @@ Ifc4x2::IfcConstructionMaterialResourceType::IfcConstructionMaterialResourceType
 
 // Function implementations for IfcConstructionProductResource
 boost::optional< ::Ifc4x2::IfcConstructionProductResourceTypeEnum::Value > Ifc4x2::IfcConstructionProductResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcConstructionProductResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcConstructionProductResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcConstructionProductResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcConstructionProductResource::declaration() const { return *IFC4X2_IfcConstructionProductResource_type; }
@@ -13396,7 +13396,7 @@ Ifc4x2::IfcConstructionProductResourceType::IfcConstructionProductResourceType(s
 ::Ifc4x2::IfcResourceTime* Ifc4x2::IfcConstructionResource::Usage() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x2::IfcResourceTime>(true); }
 void Ifc4x2::IfcConstructionResource::setUsage(::Ifc4x2::IfcResourceTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcAppliedValue >::ptr > Ifc4x2::IfcConstructionResource::BaseCosts() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x2::IfcAppliedValue >(); }
-void Ifc4x2::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x2::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x2::IfcPhysicalQuantity* Ifc4x2::IfcConstructionResource::BaseQuantity() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x2::IfcPhysicalQuantity>(true); }
 void Ifc4x2::IfcConstructionResource::setBaseQuantity(::Ifc4x2::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -13408,7 +13408,7 @@ Ifc4x2::IfcConstructionResource::IfcConstructionResource(std::string v1_GlobalId
 
 // Function implementations for IfcConstructionResourceType
 boost::optional< aggregate_of< ::Ifc4x2::IfcAppliedValue >::ptr > Ifc4x2::IfcConstructionResourceType::BaseCosts() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x2::IfcAppliedValue >(); }
-void Ifc4x2::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x2::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 ::Ifc4x2::IfcPhysicalQuantity* Ifc4x2::IfcConstructionResourceType::BaseQuantity() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x2::IfcPhysicalQuantity>(true); }
 void Ifc4x2::IfcConstructionResourceType::setBaseQuantity(::Ifc4x2::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -13420,13 +13420,13 @@ Ifc4x2::IfcConstructionResourceType::IfcConstructionResourceType(std::string v1_
 
 // Function implementations for IfcContext
 boost::optional< std::string > Ifc4x2::IfcContext::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcContext::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcContext::Phase() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcRepresentationContext >::ptr > Ifc4x2::IfcContext::RepresentationContexts() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x2::IfcRepresentationContext >(); }
-void Ifc4x2::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x2::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x2::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x2::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 ::Ifc4x2::IfcUnitAssignment* Ifc4x2::IfcContext::UnitsInContext() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x2::IfcUnitAssignment>(true); }
 void Ifc4x2::IfcContext::setUnitsInContext(::Ifc4x2::IfcUnitAssignment* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -13451,7 +13451,7 @@ Ifc4x2::IfcContextDependentUnit::IfcContextDependentUnit(::Ifc4x2::IfcDimensiona
 
 // Function implementations for IfcControl
 boost::optional< std::string > Ifc4x2::IfcControl::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x2::IfcRelAssignsToControl::list::ptr Ifc4x2::IfcControl::Controls() const { return data_->getInverse(IFC4X2_IfcRelAssignsToControl_type, 6)->as<IfcRelAssignsToControl>(); }
 
@@ -13462,7 +13462,7 @@ Ifc4x2::IfcControl::IfcControl(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistor
 
 // Function implementations for IfcController
 boost::optional< ::Ifc4x2::IfcControllerTypeEnum::Value > Ifc4x2::IfcController::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcControllerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcController::setPredefinedType(boost::optional< ::Ifc4x2::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcControllerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcController::setPredefinedType(boost::optional< ::Ifc4x2::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcControllerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcController::declaration() const { return *IFC4X2_IfcController_type; }
@@ -13505,7 +13505,7 @@ Ifc4x2::IfcConversionBasedUnitWithOffset::IfcConversionBasedUnitWithOffset(::Ifc
 
 // Function implementations for IfcCooledBeam
 boost::optional< ::Ifc4x2::IfcCooledBeamTypeEnum::Value > Ifc4x2::IfcCooledBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCooledBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x2::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCooledBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x2::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCooledBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCooledBeam::declaration() const { return *IFC4X2_IfcCooledBeam_type; }
@@ -13525,7 +13525,7 @@ Ifc4x2::IfcCooledBeamType::IfcCooledBeamType(std::string v1_GlobalId, ::Ifc4x2::
 
 // Function implementations for IfcCoolingTower
 boost::optional< ::Ifc4x2::IfcCoolingTowerTypeEnum::Value > Ifc4x2::IfcCoolingTower::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCoolingTowerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x2::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCoolingTowerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x2::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCoolingTowerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCoolingTower::declaration() const { return *IFC4X2_IfcCoolingTower_type; }
@@ -13559,11 +13559,11 @@ Ifc4x2::IfcCoordinateOperation::IfcCoordinateOperation(::Ifc4x2::IfcCoordinateRe
 std::string Ifc4x2::IfcCoordinateReferenceSystem::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcCoordinateReferenceSystem::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcCoordinateReferenceSystem::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcCoordinateReferenceSystem::GeodeticDatum() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x2::IfcCoordinateReferenceSystem::VerticalDatum() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 ::Ifc4x2::IfcCoordinateOperation::list::ptr Ifc4x2::IfcCoordinateReferenceSystem::HasCoordinateOperation() const { return data_->getInverse(IFC4X2_IfcCoordinateOperation_type, 0)->as<IfcCoordinateOperation>(); }
 
@@ -13574,11 +13574,11 @@ Ifc4x2::IfcCoordinateReferenceSystem::IfcCoordinateReferenceSystem(std::string v
 
 // Function implementations for IfcCostItem
 boost::optional< ::Ifc4x2::IfcCostItemTypeEnum::Value > Ifc4x2::IfcCostItem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCostItemTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x2::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x2::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCostItemTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x2::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x2::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCostItemTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcCostValue >::ptr > Ifc4x2::IfcCostItem::CostValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x2::IfcCostValue >(); }
-void Ifc4x2::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x2::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x2::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x2::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcPhysicalQuantity >::ptr > Ifc4x2::IfcCostItem::CostQuantities() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x2::IfcPhysicalQuantity >(); }
-void Ifc4x2::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x2::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x2::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCostItem::declaration() const { return *IFC4X2_IfcCostItem_type; }
@@ -13588,13 +13588,13 @@ Ifc4x2::IfcCostItem::IfcCostItem(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHist
 
 // Function implementations for IfcCostSchedule
 boost::optional< ::Ifc4x2::IfcCostScheduleTypeEnum::Value > Ifc4x2::IfcCostSchedule::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCostScheduleTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x2::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x2::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCostScheduleTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x2::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x2::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCostScheduleTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcCostSchedule::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcCostSchedule::SubmittedOn() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x2::IfcCostSchedule::UpdateDate() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCostSchedule::declaration() const { return *IFC4X2_IfcCostSchedule_type; }
@@ -13612,7 +13612,7 @@ Ifc4x2::IfcCostValue::IfcCostValue(boost::optional< std::string > v1_Name, boost
 
 // Function implementations for IfcCovering
 boost::optional< ::Ifc4x2::IfcCoveringTypeEnum::Value > Ifc4x2::IfcCovering::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCoveringTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x2::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCoveringTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x2::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCoveringTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x2::IfcRelCoversSpaces::list::ptr Ifc4x2::IfcCovering::CoversSpaces() const { return data_->getInverse(IFC4X2_IfcRelCoversSpaces_type, 5)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x2::IfcRelCoversBldgElements::list::ptr Ifc4x2::IfcCovering::CoversElements() const { return data_->getInverse(IFC4X2_IfcRelCoversBldgElements_type, 5)->as<IfcRelCoversBldgElements>(); }
@@ -13634,7 +13634,7 @@ Ifc4x2::IfcCoveringType::IfcCoveringType(std::string v1_GlobalId, ::Ifc4x2::IfcO
 
 // Function implementations for IfcCrewResource
 boost::optional< ::Ifc4x2::IfcCrewResourceTypeEnum::Value > Ifc4x2::IfcCrewResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCrewResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCrewResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCrewResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCrewResource::declaration() const { return *IFC4X2_IfcCrewResource_type; }
@@ -13680,7 +13680,7 @@ void Ifc4x2::IfcCurrencyRelationship::setRelatedMonetaryUnit(::Ifc4x2::IfcMoneta
 double Ifc4x2::IfcCurrencyRelationship::ExchangeRate() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x2::IfcCurrencyRelationship::setExchangeRate(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcCurrencyRelationship::RateDateTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x2::IfcLibraryInformation* Ifc4x2::IfcCurrencyRelationship::RateSource() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcLibraryInformation>(true); }
 void Ifc4x2::IfcCurrencyRelationship::setRateSource(::Ifc4x2::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -13692,7 +13692,7 @@ Ifc4x2::IfcCurrencyRelationship::IfcCurrencyRelationship(boost::optional< std::s
 
 // Function implementations for IfcCurtainWall
 boost::optional< ::Ifc4x2::IfcCurtainWallTypeEnum::Value > Ifc4x2::IfcCurtainWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCurtainWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x2::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCurtainWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x2::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCurtainWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCurtainWall::declaration() const { return *IFC4X2_IfcCurtainWall_type; }
@@ -13768,7 +13768,7 @@ void Ifc4x2::IfcCurveStyle::setCurveWidth(::Ifc4x2::IfcSizeSelect* v) { {IfcWrit
 ::Ifc4x2::IfcColour* Ifc4x2::IfcCurveStyle::CurveColour() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcColour>(true); }
 void Ifc4x2::IfcCurveStyle::setCurveColour(::Ifc4x2::IfcColour* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x2::IfcCurveStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcCurveStyle::declaration() const { return *IFC4X2_IfcCurveStyle_type; }
@@ -13778,7 +13778,7 @@ Ifc4x2::IfcCurveStyle::IfcCurveStyle(boost::optional< std::string > v1_Name, ::I
 
 // Function implementations for IfcCurveStyleFont
 boost::optional< std::string > Ifc4x2::IfcCurveStyleFont::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc4x2::IfcCurveStyleFontPattern >::ptr Ifc4x2::IfcCurveStyleFont::PatternList() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x2::IfcCurveStyleFontPattern >(); }
 void Ifc4x2::IfcCurveStyleFont::setPatternList(aggregate_of< ::Ifc4x2::IfcCurveStyleFontPattern >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -13790,7 +13790,7 @@ Ifc4x2::IfcCurveStyleFont::IfcCurveStyleFont(boost::optional< std::string > v1_N
 
 // Function implementations for IfcCurveStyleFontAndScaling
 boost::optional< std::string > Ifc4x2::IfcCurveStyleFontAndScaling::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x2::IfcCurveStyleFontSelect* Ifc4x2::IfcCurveStyleFontAndScaling::CurveFont() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x2::IfcCurveStyleFontSelect>(true); }
 void Ifc4x2::IfcCurveStyleFontAndScaling::setCurveFont(::Ifc4x2::IfcCurveStyleFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 double Ifc4x2::IfcCurveStyleFontAndScaling::CurveFontScaling() const {  double v = *data_->getArgument(2); return v; }
@@ -13826,7 +13826,7 @@ Ifc4x2::IfcCylindricalSurface::IfcCylindricalSurface(::Ifc4x2::IfcAxis2Placement
 
 // Function implementations for IfcDamper
 boost::optional< ::Ifc4x2::IfcDamperTypeEnum::Value > Ifc4x2::IfcDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x2::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x2::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDamper::declaration() const { return *IFC4X2_IfcDamper_type; }
@@ -13866,7 +13866,7 @@ void Ifc4x2::IfcDerivedProfileDef::setParentProfile(::Ifc4x2::IfcProfileDef* v)
 ::Ifc4x2::IfcCartesianTransformationOperator2D* Ifc4x2::IfcDerivedProfileDef::Operator() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x2::IfcDerivedProfileDef::setOperator(::Ifc4x2::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDerivedProfileDef::Label() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDerivedProfileDef::declaration() const { return *IFC4X2_IfcDerivedProfileDef_type; }
@@ -13880,7 +13880,7 @@ void Ifc4x2::IfcDerivedUnit::setElements(aggregate_of< ::Ifc4x2::IfcDerivedUnitE
 ::Ifc4x2::IfcDerivedUnitEnum::Value Ifc4x2::IfcDerivedUnit::UnitType() const {  return ::Ifc4x2::IfcDerivedUnitEnum::FromString(*data_->getArgument(1)); }
 void Ifc4x2::IfcDerivedUnit::setUnitType(::Ifc4x2::IfcDerivedUnitEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcDerivedUnitEnum::ToString(v)));data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDerivedUnit::UserDefinedType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDerivedUnit::declaration() const { return *IFC4X2_IfcDerivedUnit_type; }
@@ -13934,7 +13934,7 @@ Ifc4x2::IfcDirection::IfcDirection(std::vector< double > /*[2:3]*/ v1_DirectionR
 
 // Function implementations for IfcDiscreteAccessory
 boost::optional< ::Ifc4x2::IfcDiscreteAccessoryTypeEnum::Value > Ifc4x2::IfcDiscreteAccessory::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDiscreteAccessoryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x2::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDiscreteAccessoryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x2::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDiscreteAccessoryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDiscreteAccessory::declaration() const { return *IFC4X2_IfcDiscreteAccessory_type; }
@@ -13956,13 +13956,13 @@ Ifc4x2::IfcDiscreteAccessoryType::IfcDiscreteAccessoryType(std::string v1_Global
 double Ifc4x2::IfcDistanceExpression::DistanceAlong() const {  double v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcDistanceExpression::setDistanceAlong(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x2::IfcDistanceExpression::OffsetLateral() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcDistanceExpression::OffsetVertical() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcDistanceExpression::OffsetLongitudinal() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x2::IfcDistanceExpression::AlongHorizontal() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcDistanceExpression::setAlongHorizontal(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcDistanceExpression::setAlongHorizontal(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDistanceExpression::declaration() const { return *IFC4X2_IfcDistanceExpression_type; }
@@ -13972,7 +13972,7 @@ Ifc4x2::IfcDistanceExpression::IfcDistanceExpression(double v1_DistanceAlong, bo
 
 // Function implementations for IfcDistributionChamberElement
 boost::optional< ::Ifc4x2::IfcDistributionChamberElementTypeEnum::Value > Ifc4x2::IfcDistributionChamberElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDistributionChamberElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDistributionChamberElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDistributionChamberElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDistributionChamberElement::declaration() const { return *IFC4X2_IfcDistributionChamberElement_type; }
@@ -14051,11 +14051,11 @@ Ifc4x2::IfcDistributionFlowElementType::IfcDistributionFlowElementType(std::stri
 
 // Function implementations for IfcDistributionPort
 boost::optional< ::Ifc4x2::IfcFlowDirectionEnum::Value > Ifc4x2::IfcDistributionPort::FlowDirection() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x2::IfcFlowDirectionEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x2::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x2::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFlowDirectionEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x2::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x2::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFlowDirectionEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x2::IfcDistributionPortTypeEnum::Value > Ifc4x2::IfcDistributionPort::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDistributionPortTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x2::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDistributionPortTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x2::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDistributionPortTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x2::IfcDistributionSystemEnum::Value > Ifc4x2::IfcDistributionPort::SystemType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDistributionSystemEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x2::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x2::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x2::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x2::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDistributionPort::declaration() const { return *IFC4X2_IfcDistributionPort_type; }
@@ -14065,9 +14065,9 @@ Ifc4x2::IfcDistributionPort::IfcDistributionPort(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcDistributionSystem
 boost::optional< std::string > Ifc4x2::IfcDistributionSystem::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< ::Ifc4x2::IfcDistributionSystemEnum::Value > Ifc4x2::IfcDistributionSystem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDistributionSystemEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x2::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x2::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x2::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x2::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDistributionSystem::declaration() const { return *IFC4X2_IfcDistributionSystem_type; }
@@ -14081,35 +14081,35 @@ void Ifc4x2::IfcDocumentInformation::setIdentification(std::string v) { {IfcWrit
 std::string Ifc4x2::IfcDocumentInformation::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcDocumentInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::Location() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::Purpose() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::IntendedUse() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::Scope() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::Revision() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x2::IfcActorSelect* Ifc4x2::IfcDocumentInformation::DocumentOwner() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x2::IfcActorSelect>(true); }
 void Ifc4x2::IfcDocumentInformation::setDocumentOwner(::Ifc4x2::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x2::IfcDocumentInformation::Editors() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::CreationTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::LastRevisionTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::ElectronicFormat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::ValidFrom() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x2::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x2::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformation::ValidUntil() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x2::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x2::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< ::Ifc4x2::IfcDocumentConfidentialityEnum::Value > Ifc4x2::IfcDocumentInformation::Confidentiality() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDocumentConfidentialityEnum::FromString(*data_->getArgument(15)); }
-void Ifc4x2::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x2::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDocumentConfidentialityEnum::ToString(*v)));data_->setArgument(15,attr);} }
+void Ifc4x2::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x2::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDocumentConfidentialityEnum::ToString(*v)));}data_->setArgument(15,attr);} }
 boost::optional< ::Ifc4x2::IfcDocumentStatusEnum::Value > Ifc4x2::IfcDocumentInformation::Status() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDocumentStatusEnum::FromString(*data_->getArgument(16)); }
-void Ifc4x2::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x2::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDocumentStatusEnum::ToString(*v)));data_->setArgument(16,attr);} }
+void Ifc4x2::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x2::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDocumentStatusEnum::ToString(*v)));}data_->setArgument(16,attr);} }
 
 ::Ifc4x2::IfcRelAssociatesDocument::list::ptr Ifc4x2::IfcDocumentInformation::DocumentInfoForObjects() const { return data_->getInverse(IFC4X2_IfcRelAssociatesDocument_type, 5)->as<IfcRelAssociatesDocument>(); }
 ::Ifc4x2::IfcDocumentReference::list::ptr Ifc4x2::IfcDocumentInformation::HasDocumentReferences() const { return data_->getInverse(IFC4X2_IfcDocumentReference_type, 4)->as<IfcDocumentReference>(); }
@@ -14127,7 +14127,7 @@ void Ifc4x2::IfcDocumentInformationRelationship::setRelatingDocument(::Ifc4x2::I
 aggregate_of< ::Ifc4x2::IfcDocumentInformation >::ptr Ifc4x2::IfcDocumentInformationRelationship::RelatedDocuments() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x2::IfcDocumentInformation >(); }
 void Ifc4x2::IfcDocumentInformationRelationship::setRelatedDocuments(aggregate_of< ::Ifc4x2::IfcDocumentInformation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDocumentInformationRelationship::RelationshipType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDocumentInformationRelationship::declaration() const { return *IFC4X2_IfcDocumentInformationRelationship_type; }
@@ -14137,7 +14137,7 @@ Ifc4x2::IfcDocumentInformationRelationship::IfcDocumentInformationRelationship(b
 
 // Function implementations for IfcDocumentReference
 boost::optional< std::string > Ifc4x2::IfcDocumentReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x2::IfcDocumentInformation* Ifc4x2::IfcDocumentReference::ReferencedDocument() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x2::IfcDocumentInformation>(true); }
 void Ifc4x2::IfcDocumentReference::setReferencedDocument(::Ifc4x2::IfcDocumentInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -14150,15 +14150,15 @@ Ifc4x2::IfcDocumentReference::IfcDocumentReference(boost::optional< std::string
 
 // Function implementations for IfcDoor
 boost::optional< double > Ifc4x2::IfcDoor::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x2::IfcDoor::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x2::IfcDoorTypeEnum::Value > Ifc4x2::IfcDoor::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDoorTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x2::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDoorTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x2::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDoorTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x2::IfcDoorTypeOperationEnum::Value > Ifc4x2::IfcDoor::OperationType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x2::IfcDoor::setOperationType(boost::optional< ::Ifc4x2::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDoorTypeOperationEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x2::IfcDoor::setOperationType(boost::optional< ::Ifc4x2::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDoorTypeOperationEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDoor::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDoor::declaration() const { return *IFC4X2_IfcDoor_type; }
@@ -14168,31 +14168,31 @@ Ifc4x2::IfcDoor::IfcDoor(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory* v2_
 
 // Function implementations for IfcDoorLiningProperties
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::ThresholdDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::ThresholdThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::TransomThickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::TransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::LiningOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::ThresholdOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::CasingThickness() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::CasingDepth() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 ::Ifc4x2::IfcShapeAspect* Ifc4x2::IfcDoorLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(14)))->as<::Ifc4x2::IfcShapeAspect>(true); }
 void Ifc4x2::IfcDoorLiningProperties::setShapeAspectStyle(::Ifc4x2::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x2::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x2::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDoorLiningProperties::declaration() const { return *IFC4X2_IfcDoorLiningProperties_type; }
@@ -14202,11 +14202,11 @@ Ifc4x2::IfcDoorLiningProperties::IfcDoorLiningProperties(std::string v1_GlobalId
 
 // Function implementations for IfcDoorPanelProperties
 boost::optional< double > Ifc4x2::IfcDoorPanelProperties::PanelDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x2::IfcDoorPanelOperationEnum::Value Ifc4x2::IfcDoorPanelProperties::PanelOperation() const {  return ::Ifc4x2::IfcDoorPanelOperationEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x2::IfcDoorPanelProperties::setPanelOperation(::Ifc4x2::IfcDoorPanelOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcDoorPanelOperationEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcDoorPanelProperties::PanelWidth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x2::IfcDoorPanelPositionEnum::Value Ifc4x2::IfcDoorPanelProperties::PanelPosition() const {  return ::Ifc4x2::IfcDoorPanelPositionEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x2::IfcDoorPanelProperties::setPanelPosition(::Ifc4x2::IfcDoorPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcDoorPanelPositionEnum::ToString(v)));data_->setArgument(7,attr);} }
 ::Ifc4x2::IfcShapeAspect* Ifc4x2::IfcDoorPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x2::IfcShapeAspect>(true); }
@@ -14248,9 +14248,9 @@ void Ifc4x2::IfcDoorType::setPredefinedType(::Ifc4x2::IfcDoorTypeEnum::Value v)
 ::Ifc4x2::IfcDoorTypeOperationEnum::Value Ifc4x2::IfcDoorType::OperationType() const {  return ::Ifc4x2::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x2::IfcDoorType::setOperationType(::Ifc4x2::IfcDoorTypeOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcDoorTypeOperationEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x2::IfcDoorType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x2::IfcDoorType::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDoorType::declaration() const { return *IFC4X2_IfcDoorType_type; }
@@ -14276,7 +14276,7 @@ Ifc4x2::IfcDraughtingPreDefinedCurveFont::IfcDraughtingPreDefinedCurveFont(std::
 
 // Function implementations for IfcDuctFitting
 boost::optional< ::Ifc4x2::IfcDuctFittingTypeEnum::Value > Ifc4x2::IfcDuctFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDuctFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x2::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDuctFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x2::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDuctFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDuctFitting::declaration() const { return *IFC4X2_IfcDuctFitting_type; }
@@ -14296,7 +14296,7 @@ Ifc4x2::IfcDuctFittingType::IfcDuctFittingType(std::string v1_GlobalId, ::Ifc4x2
 
 // Function implementations for IfcDuctSegment
 boost::optional< ::Ifc4x2::IfcDuctSegmentTypeEnum::Value > Ifc4x2::IfcDuctSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDuctSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x2::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDuctSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x2::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDuctSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDuctSegment::declaration() const { return *IFC4X2_IfcDuctSegment_type; }
@@ -14316,7 +14316,7 @@ Ifc4x2::IfcDuctSegmentType::IfcDuctSegmentType(std::string v1_GlobalId, ::Ifc4x2
 
 // Function implementations for IfcDuctSilencer
 boost::optional< ::Ifc4x2::IfcDuctSilencerTypeEnum::Value > Ifc4x2::IfcDuctSilencer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDuctSilencerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x2::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDuctSilencerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x2::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDuctSilencerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcDuctSilencer::declaration() const { return *IFC4X2_IfcDuctSilencer_type; }
@@ -14370,7 +14370,7 @@ Ifc4x2::IfcEdgeLoop::IfcEdgeLoop(aggregate_of< ::Ifc4x2::IfcOrientedEdge >::ptr
 
 // Function implementations for IfcElectricAppliance
 boost::optional< ::Ifc4x2::IfcElectricApplianceTypeEnum::Value > Ifc4x2::IfcElectricAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcElectricApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcElectricAppliance::declaration() const { return *IFC4X2_IfcElectricAppliance_type; }
@@ -14390,7 +14390,7 @@ Ifc4x2::IfcElectricApplianceType::IfcElectricApplianceType(std::string v1_Global
 
 // Function implementations for IfcElectricDistributionBoard
 boost::optional< ::Ifc4x2::IfcElectricDistributionBoardTypeEnum::Value > Ifc4x2::IfcElectricDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcElectricDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcElectricDistributionBoard::declaration() const { return *IFC4X2_IfcElectricDistributionBoard_type; }
@@ -14410,7 +14410,7 @@ Ifc4x2::IfcElectricDistributionBoardType::IfcElectricDistributionBoardType(std::
 
 // Function implementations for IfcElectricFlowStorageDevice
 boost::optional< ::Ifc4x2::IfcElectricFlowStorageDeviceTypeEnum::Value > Ifc4x2::IfcElectricFlowStorageDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcElectricFlowStorageDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcElectricFlowStorageDevice::declaration() const { return *IFC4X2_IfcElectricFlowStorageDevice_type; }
@@ -14430,7 +14430,7 @@ Ifc4x2::IfcElectricFlowStorageDeviceType::IfcElectricFlowStorageDeviceType(std::
 
 // Function implementations for IfcElectricGenerator
 boost::optional< ::Ifc4x2::IfcElectricGeneratorTypeEnum::Value > Ifc4x2::IfcElectricGenerator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcElectricGeneratorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricGeneratorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricGeneratorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcElectricGenerator::declaration() const { return *IFC4X2_IfcElectricGenerator_type; }
@@ -14450,7 +14450,7 @@ Ifc4x2::IfcElectricGeneratorType::IfcElectricGeneratorType(std::string v1_Global
 
 // Function implementations for IfcElectricMotor
 boost::optional< ::Ifc4x2::IfcElectricMotorTypeEnum::Value > Ifc4x2::IfcElectricMotor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcElectricMotorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricMotorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricMotorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcElectricMotor::declaration() const { return *IFC4X2_IfcElectricMotor_type; }
@@ -14470,7 +14470,7 @@ Ifc4x2::IfcElectricMotorType::IfcElectricMotorType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcElectricTimeControl
 boost::optional< ::Ifc4x2::IfcElectricTimeControlTypeEnum::Value > Ifc4x2::IfcElectricTimeControl::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcElectricTimeControlTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricTimeControlTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x2::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElectricTimeControlTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcElectricTimeControl::declaration() const { return *IFC4X2_IfcElectricTimeControl_type; }
@@ -14490,7 +14490,7 @@ Ifc4x2::IfcElectricTimeControlType::IfcElectricTimeControlType(std::string v1_Gl
 
 // Function implementations for IfcElement
 boost::optional< std::string > Ifc4x2::IfcElement::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x2::IfcRelFillsElement::list::ptr Ifc4x2::IfcElement::FillsVoids() const { return data_->getInverse(IFC4X2_IfcRelFillsElement_type, 5)->as<IfcRelFillsElement>(); }
 ::Ifc4x2::IfcRelConnectsElements::list::ptr Ifc4x2::IfcElement::ConnectedTo() const { return data_->getInverse(IFC4X2_IfcRelConnectsElements_type, 5)->as<IfcRelConnectsElements>(); }
@@ -14512,9 +14512,9 @@ Ifc4x2::IfcElement::IfcElement(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistor
 
 // Function implementations for IfcElementAssembly
 boost::optional< ::Ifc4x2::IfcAssemblyPlaceEnum::Value > Ifc4x2::IfcElementAssembly::AssemblyPlace() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x2::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAssemblyPlaceEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x2::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcAssemblyPlaceEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x2::IfcElementAssemblyTypeEnum::Value > Ifc4x2::IfcElementAssembly::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x2::IfcElementAssemblyTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x2::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x2::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElementAssemblyTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x2::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x2::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElementAssemblyTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcElementAssembly::declaration() const { return *IFC4X2_IfcElementAssembly_type; }
@@ -14550,7 +14550,7 @@ Ifc4x2::IfcElementComponentType::IfcElementComponentType(std::string v1_GlobalId
 
 // Function implementations for IfcElementQuantity
 boost::optional< std::string > Ifc4x2::IfcElementQuantity::MethodOfMeasurement() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x2::IfcPhysicalQuantity >::ptr Ifc4x2::IfcElementQuantity::Quantities() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x2::IfcPhysicalQuantity >(); }
 void Ifc4x2::IfcElementQuantity::setQuantities(aggregate_of< ::Ifc4x2::IfcPhysicalQuantity >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -14562,7 +14562,7 @@ Ifc4x2::IfcElementQuantity::IfcElementQuantity(std::string v1_GlobalId, ::Ifc4x2
 
 // Function implementations for IfcElementType
 boost::optional< std::string > Ifc4x2::IfcElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcElementType::declaration() const { return *IFC4X2_IfcElementType_type; }
@@ -14622,7 +14622,7 @@ Ifc4x2::IfcEnergyConversionDeviceType::IfcEnergyConversionDeviceType(std::string
 
 // Function implementations for IfcEngine
 boost::optional< ::Ifc4x2::IfcEngineTypeEnum::Value > Ifc4x2::IfcEngine::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcEngineTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x2::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcEngineTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x2::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcEngineTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcEngine::declaration() const { return *IFC4X2_IfcEngine_type; }
@@ -14642,7 +14642,7 @@ Ifc4x2::IfcEngineType::IfcEngineType(std::string v1_GlobalId, ::Ifc4x2::IfcOwner
 
 // Function implementations for IfcEvaporativeCooler
 boost::optional< ::Ifc4x2::IfcEvaporativeCoolerTypeEnum::Value > Ifc4x2::IfcEvaporativeCooler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcEvaporativeCoolerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x2::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcEvaporativeCoolerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x2::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcEvaporativeCoolerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcEvaporativeCooler::declaration() const { return *IFC4X2_IfcEvaporativeCooler_type; }
@@ -14662,7 +14662,7 @@ Ifc4x2::IfcEvaporativeCoolerType::IfcEvaporativeCoolerType(std::string v1_Global
 
 // Function implementations for IfcEvaporator
 boost::optional< ::Ifc4x2::IfcEvaporatorTypeEnum::Value > Ifc4x2::IfcEvaporator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcEvaporatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x2::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcEvaporatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x2::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcEvaporatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcEvaporator::declaration() const { return *IFC4X2_IfcEvaporator_type; }
@@ -14682,11 +14682,11 @@ Ifc4x2::IfcEvaporatorType::IfcEvaporatorType(std::string v1_GlobalId, ::Ifc4x2::
 
 // Function implementations for IfcEvent
 boost::optional< ::Ifc4x2::IfcEventTypeEnum::Value > Ifc4x2::IfcEvent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x2::IfcEventTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x2::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x2::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcEventTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x2::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x2::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcEventTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x2::IfcEventTriggerTypeEnum::Value > Ifc4x2::IfcEvent::EventTriggerType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x2::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcEventTriggerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x2::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcEventTriggerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x2::IfcEvent::UserDefinedEventTriggerType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 ::Ifc4x2::IfcEventTime* Ifc4x2::IfcEvent::EventOccurenceTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x2::IfcEventTime>(true); }
 void Ifc4x2::IfcEvent::setEventOccurenceTime(::Ifc4x2::IfcEventTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -14698,13 +14698,13 @@ Ifc4x2::IfcEvent::IfcEvent(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory* v
 
 // Function implementations for IfcEventTime
 boost::optional< std::string > Ifc4x2::IfcEventTime::ActualDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcEventTime::EarlyDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcEventTime::LateDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcEventTime::ScheduleDate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcEventTime::declaration() const { return *IFC4X2_IfcEventTime_type; }
@@ -14718,7 +14718,7 @@ void Ifc4x2::IfcEventType::setPredefinedType(::Ifc4x2::IfcEventTypeEnum::Value v
 ::Ifc4x2::IfcEventTriggerTypeEnum::Value Ifc4x2::IfcEventType::EventTriggerType() const {  return ::Ifc4x2::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x2::IfcEventType::setEventTriggerType(::Ifc4x2::IfcEventTriggerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcEventTriggerTypeEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x2::IfcEventType::UserDefinedEventTriggerType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcEventType::declaration() const { return *IFC4X2_IfcEventType_type; }
@@ -14728,9 +14728,9 @@ Ifc4x2::IfcEventType::IfcEventType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHi
 
 // Function implementations for IfcExtendedProperties
 boost::optional< std::string > Ifc4x2::IfcExtendedProperties::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcExtendedProperties::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x2::IfcProperty >::ptr Ifc4x2::IfcExtendedProperties::Properties() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x2::IfcProperty >(); }
 void Ifc4x2::IfcExtendedProperties::setProperties(aggregate_of< ::Ifc4x2::IfcProperty >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -14750,11 +14750,11 @@ Ifc4x2::IfcExternalInformation::IfcExternalInformation() : IfcUtil::IfcBaseEntit
 
 // Function implementations for IfcExternalReference
 boost::optional< std::string > Ifc4x2::IfcExternalReference::Location() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcExternalReference::Identification() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcExternalReference::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x2::IfcExternalReferenceRelationship::list::ptr Ifc4x2::IfcExternalReference::ExternalReferenceForResources() const { return data_->getInverse(IFC4X2_IfcExternalReferenceRelationship_type, 2)->as<IfcExternalReferenceRelationship>(); }
 
@@ -14777,7 +14777,7 @@ Ifc4x2::IfcExternalReferenceRelationship::IfcExternalReferenceRelationship(boost
 
 // Function implementations for IfcExternalSpatialElement
 boost::optional< ::Ifc4x2::IfcExternalSpatialElementTypeEnum::Value > Ifc4x2::IfcExternalSpatialElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcExternalSpatialElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcExternalSpatialElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcExternalSpatialElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x2::IfcRelSpaceBoundary::list::ptr Ifc4x2::IfcExternalSpatialElement::BoundedBy() const { return data_->getInverse(IFC4X2_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
 
@@ -14929,17 +14929,17 @@ Ifc4x2::IfcFacilityPart::IfcFacilityPart(std::string v1_GlobalId, ::Ifc4x2::IfcO
 
 // Function implementations for IfcFailureConnectionCondition
 boost::optional< double > Ifc4x2::IfcFailureConnectionCondition::TensionFailureX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcFailureConnectionCondition::TensionFailureY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcFailureConnectionCondition::TensionFailureZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcFailureConnectionCondition::CompressionFailureX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x2::IfcFailureConnectionCondition::CompressionFailureY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcFailureConnectionCondition::CompressionFailureZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFailureConnectionCondition::declaration() const { return *IFC4X2_IfcFailureConnectionCondition_type; }
@@ -14949,7 +14949,7 @@ Ifc4x2::IfcFailureConnectionCondition::IfcFailureConnectionCondition(boost::opti
 
 // Function implementations for IfcFan
 boost::optional< ::Ifc4x2::IfcFanTypeEnum::Value > Ifc4x2::IfcFan::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcFanTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcFan::setPredefinedType(boost::optional< ::Ifc4x2::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFanTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcFan::setPredefinedType(boost::optional< ::Ifc4x2::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFanTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFan::declaration() const { return *IFC4X2_IfcFan_type; }
@@ -14969,7 +14969,7 @@ Ifc4x2::IfcFanType::IfcFanType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistor
 
 // Function implementations for IfcFastener
 boost::optional< ::Ifc4x2::IfcFastenerTypeEnum::Value > Ifc4x2::IfcFastener::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcFastenerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x2::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFastenerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x2::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFastenerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFastener::declaration() const { return *IFC4X2_IfcFastener_type; }
@@ -15017,7 +15017,7 @@ Ifc4x2::IfcFeatureElementSubtraction::IfcFeatureElementSubtraction(std::string v
 aggregate_of_instance::ptr Ifc4x2::IfcFillAreaStyle::FillStyles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcFillAreaStyle::setFillStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x2::IfcFillAreaStyle::ModelorDraughting() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcFillAreaStyle::setModelorDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcFillAreaStyle::setModelorDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFillAreaStyle::declaration() const { return *IFC4X2_IfcFillAreaStyle_type; }
@@ -15059,7 +15059,7 @@ Ifc4x2::IfcFillAreaStyleTiles::IfcFillAreaStyleTiles(aggregate_of< ::Ifc4x2::Ifc
 
 // Function implementations for IfcFilter
 boost::optional< ::Ifc4x2::IfcFilterTypeEnum::Value > Ifc4x2::IfcFilter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcFilterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x2::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFilterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x2::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFilterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFilter::declaration() const { return *IFC4X2_IfcFilter_type; }
@@ -15079,7 +15079,7 @@ Ifc4x2::IfcFilterType::IfcFilterType(std::string v1_GlobalId, ::Ifc4x2::IfcOwner
 
 // Function implementations for IfcFireSuppressionTerminal
 boost::optional< ::Ifc4x2::IfcFireSuppressionTerminalTypeEnum::Value > Ifc4x2::IfcFireSuppressionTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcFireSuppressionTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x2::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x2::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFireSuppressionTerminal::declaration() const { return *IFC4X2_IfcFireSuppressionTerminal_type; }
@@ -15101,9 +15101,9 @@ Ifc4x2::IfcFireSuppressionTerminalType::IfcFireSuppressionTerminalType(std::stri
 ::Ifc4x2::IfcCurve* Ifc4x2::IfcFixedReferenceSweptAreaSolid::Directrix() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x2::IfcCurve>(true); }
 void Ifc4x2::IfcFixedReferenceSweptAreaSolid::setDirectrix(::Ifc4x2::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcFixedReferenceSweptAreaSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcFixedReferenceSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcFixedReferenceSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcFixedReferenceSweptAreaSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcFixedReferenceSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcFixedReferenceSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x2::IfcDirection* Ifc4x2::IfcFixedReferenceSweptAreaSolid::FixedReference() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x2::IfcDirection>(true); }
 void Ifc4x2::IfcFixedReferenceSweptAreaSolid::setFixedReference(::Ifc4x2::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -15147,7 +15147,7 @@ Ifc4x2::IfcFlowFittingType::IfcFlowFittingType(std::string v1_GlobalId, ::Ifc4x2
 
 // Function implementations for IfcFlowInstrument
 boost::optional< ::Ifc4x2::IfcFlowInstrumentTypeEnum::Value > Ifc4x2::IfcFlowInstrument::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcFlowInstrumentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x2::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFlowInstrumentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x2::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFlowInstrumentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFlowInstrument::declaration() const { return *IFC4X2_IfcFlowInstrument_type; }
@@ -15167,7 +15167,7 @@ Ifc4x2::IfcFlowInstrumentType::IfcFlowInstrumentType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcFlowMeter
 boost::optional< ::Ifc4x2::IfcFlowMeterTypeEnum::Value > Ifc4x2::IfcFlowMeter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcFlowMeterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x2::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFlowMeterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x2::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFlowMeterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFlowMeter::declaration() const { return *IFC4X2_IfcFlowMeter_type; }
@@ -15267,7 +15267,7 @@ Ifc4x2::IfcFlowTreatmentDeviceType::IfcFlowTreatmentDeviceType(std::string v1_Gl
 
 // Function implementations for IfcFooting
 boost::optional< ::Ifc4x2::IfcFootingTypeEnum::Value > Ifc4x2::IfcFooting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcFootingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x2::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFootingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x2::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFootingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFooting::declaration() const { return *IFC4X2_IfcFooting_type; }
@@ -15303,7 +15303,7 @@ Ifc4x2::IfcFurnishingElementType::IfcFurnishingElementType(std::string v1_Global
 
 // Function implementations for IfcFurniture
 boost::optional< ::Ifc4x2::IfcFurnitureTypeEnum::Value > Ifc4x2::IfcFurniture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcFurnitureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x2::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x2::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFurniture::declaration() const { return *IFC4X2_IfcFurniture_type; }
@@ -15315,7 +15315,7 @@ Ifc4x2::IfcFurniture::IfcFurniture(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHi
 ::Ifc4x2::IfcAssemblyPlaceEnum::Value Ifc4x2::IfcFurnitureType::AssemblyPlace() const {  return ::Ifc4x2::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x2::IfcFurnitureType::setAssemblyPlace(::Ifc4x2::IfcAssemblyPlaceEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcAssemblyPlaceEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x2::IfcFurnitureTypeEnum::Value > Ifc4x2::IfcFurnitureType::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcFurnitureTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x2::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x2::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcFurnitureType::declaration() const { return *IFC4X2_IfcFurnitureType_type; }
@@ -15325,7 +15325,7 @@ Ifc4x2::IfcFurnitureType::IfcFurnitureType(std::string v1_GlobalId, ::Ifc4x2::If
 
 // Function implementations for IfcGeographicElement
 boost::optional< ::Ifc4x2::IfcGeographicElementTypeEnum::Value > Ifc4x2::IfcGeographicElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcGeographicElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcGeographicElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcGeographicElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcGeographicElement::declaration() const { return *IFC4X2_IfcGeographicElement_type; }
@@ -15355,7 +15355,7 @@ Ifc4x2::IfcGeometricCurveSet::IfcGeometricCurveSet(aggregate_of_instance::ptr v1
 int Ifc4x2::IfcGeometricRepresentationContext::CoordinateSpaceDimension() const {  int v = *data_->getArgument(2); return v; }
 void Ifc4x2::IfcGeometricRepresentationContext::setCoordinateSpaceDimension(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcGeometricRepresentationContext::Precision() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x2::IfcAxis2Placement* Ifc4x2::IfcGeometricRepresentationContext::WorldCoordinateSystem() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x2::IfcAxis2Placement>(true); }
 void Ifc4x2::IfcGeometricRepresentationContext::setWorldCoordinateSystem(::Ifc4x2::IfcAxis2Placement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 ::Ifc4x2::IfcDirection* Ifc4x2::IfcGeometricRepresentationContext::TrueNorth() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x2::IfcDirection>(true); }
@@ -15381,11 +15381,11 @@ Ifc4x2::IfcGeometricRepresentationItem::IfcGeometricRepresentationItem() : IfcRe
 ::Ifc4x2::IfcGeometricRepresentationContext* Ifc4x2::IfcGeometricRepresentationSubContext::ParentContext() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcGeometricRepresentationContext>(true); }
 void Ifc4x2::IfcGeometricRepresentationSubContext::setParentContext(::Ifc4x2::IfcGeometricRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcGeometricRepresentationSubContext::TargetScale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x2::IfcGeometricProjectionEnum::Value Ifc4x2::IfcGeometricRepresentationSubContext::TargetView() const {  return ::Ifc4x2::IfcGeometricProjectionEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x2::IfcGeometricRepresentationSubContext::setTargetView(::Ifc4x2::IfcGeometricProjectionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcGeometricProjectionEnum::ToString(v)));data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x2::IfcGeometricRepresentationSubContext::UserDefinedTargetView() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcGeometricRepresentationSubContext::declaration() const { return *IFC4X2_IfcGeometricRepresentationSubContext_type; }
@@ -15409,9 +15409,9 @@ void Ifc4x2::IfcGrid::setUAxes(aggregate_of< ::Ifc4x2::IfcGridAxis >::ptr v) { {
 aggregate_of< ::Ifc4x2::IfcGridAxis >::ptr Ifc4x2::IfcGrid::VAxes() const {  aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x2::IfcGridAxis >(); }
 void Ifc4x2::IfcGrid::setVAxes(aggregate_of< ::Ifc4x2::IfcGridAxis >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcGridAxis >::ptr > Ifc4x2::IfcGrid::WAxes() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x2::IfcGridAxis >(); }
-void Ifc4x2::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x2::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x2::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x2::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x2::IfcGridTypeEnum::Value > Ifc4x2::IfcGrid::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcGridTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x2::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcGridTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x2::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcGridTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcGrid::declaration() const { return *IFC4X2_IfcGrid_type; }
@@ -15421,7 +15421,7 @@ Ifc4x2::IfcGrid::IfcGrid(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory* v2_
 
 // Function implementations for IfcGridAxis
 boost::optional< std::string > Ifc4x2::IfcGridAxis::AxisTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x2::IfcCurve* Ifc4x2::IfcGridAxis::AxisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x2::IfcCurve>(true); }
 void Ifc4x2::IfcGridAxis::setAxisCurve(::Ifc4x2::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 bool Ifc4x2::IfcGridAxis::SameSense() const {  bool v = *data_->getArgument(2); return v; }
@@ -15472,7 +15472,7 @@ Ifc4x2::IfcHalfSpaceSolid::IfcHalfSpaceSolid(::Ifc4x2::IfcSurface* v1_BaseSurfac
 
 // Function implementations for IfcHeatExchanger
 boost::optional< ::Ifc4x2::IfcHeatExchangerTypeEnum::Value > Ifc4x2::IfcHeatExchanger::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcHeatExchangerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x2::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcHeatExchangerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x2::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcHeatExchangerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcHeatExchanger::declaration() const { return *IFC4X2_IfcHeatExchanger_type; }
@@ -15492,7 +15492,7 @@ Ifc4x2::IfcHeatExchangerType::IfcHeatExchangerType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcHumidifier
 boost::optional< ::Ifc4x2::IfcHumidifierTypeEnum::Value > Ifc4x2::IfcHumidifier::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcHumidifierTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x2::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcHumidifierTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x2::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcHumidifierTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcHumidifier::declaration() const { return *IFC4X2_IfcHumidifier_type; }
@@ -15520,11 +15520,11 @@ void Ifc4x2::IfcIShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc4x2::IfcIShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x2::IfcIShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcIShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcIShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x2::IfcIShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcIShapeProfileDef::declaration() const { return *IFC4X2_IfcIShapeProfileDef_type; }
@@ -15546,7 +15546,7 @@ Ifc4x2::IfcImageTexture::IfcImageTexture(bool v1_RepeatS, bool v2_RepeatT, boost
 ::Ifc4x2::IfcTessellatedFaceSet* Ifc4x2::IfcIndexedColourMap::MappedTo() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x2::IfcTessellatedFaceSet>(true); }
 void Ifc4x2::IfcIndexedColourMap::setMappedTo(::Ifc4x2::IfcTessellatedFaceSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x2::IfcIndexedColourMap::Opacity() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x2::IfcColourRgbList* Ifc4x2::IfcIndexedColourMap::Colours() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x2::IfcColourRgbList>(true); }
 void Ifc4x2::IfcIndexedColourMap::setColours(::Ifc4x2::IfcColourRgbList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::vector< int > /*[1:?]*/ Ifc4x2::IfcIndexedColourMap::ColourIndex() const {  std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
@@ -15562,9 +15562,9 @@ Ifc4x2::IfcIndexedColourMap::IfcIndexedColourMap(::Ifc4x2::IfcTessellatedFaceSet
 ::Ifc4x2::IfcCartesianPointList* Ifc4x2::IfcIndexedPolyCurve::Points() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x2::IfcCartesianPointList>(true); }
 void Ifc4x2::IfcIndexedPolyCurve::setPoints(::Ifc4x2::IfcCartesianPointList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x2::IfcIndexedPolyCurve::Segments() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x2::IfcIndexedPolyCurve::SelfIntersect() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcIndexedPolyCurve::declaration() const { return *IFC4X2_IfcIndexedPolyCurve_type; }
@@ -15607,7 +15607,7 @@ Ifc4x2::IfcIndexedTextureMap::IfcIndexedTextureMap(aggregate_of< ::Ifc4x2::IfcSu
 
 // Function implementations for IfcIndexedTriangleTextureMap
 boost::optional< std::vector< std::vector< int > > > Ifc4x2::IfcIndexedTriangleTextureMap::TexCoordIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcIndexedTriangleTextureMap::declaration() const { return *IFC4X2_IfcIndexedTriangleTextureMap_type; }
@@ -15617,7 +15617,7 @@ Ifc4x2::IfcIndexedTriangleTextureMap::IfcIndexedTriangleTextureMap(aggregate_of<
 
 // Function implementations for IfcInterceptor
 boost::optional< ::Ifc4x2::IfcInterceptorTypeEnum::Value > Ifc4x2::IfcInterceptor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcInterceptorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x2::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcInterceptorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x2::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcInterceptorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcInterceptor::declaration() const { return *IFC4X2_IfcInterceptor_type; }
@@ -15645,13 +15645,13 @@ Ifc4x2::IfcIntersectionCurve::IfcIntersectionCurve(::Ifc4x2::IfcCurve* v1_Curve3
 
 // Function implementations for IfcInventory
 boost::optional< ::Ifc4x2::IfcInventoryTypeEnum::Value > Ifc4x2::IfcInventory::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x2::IfcInventoryTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x2::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x2::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcInventoryTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x2::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x2::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcInventoryTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 ::Ifc4x2::IfcActorSelect* Ifc4x2::IfcInventory::Jurisdiction() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcActorSelect>(true); }
 void Ifc4x2::IfcInventory::setJurisdiction(::Ifc4x2::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcPerson >::ptr > Ifc4x2::IfcInventory::ResponsiblePersons() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x2::IfcPerson >(); }
-void Ifc4x2::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x2::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x2::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x2::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcInventory::LastUpdateDate() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x2::IfcCostValue* Ifc4x2::IfcInventory::CurrentValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x2::IfcCostValue>(true); }
 void Ifc4x2::IfcInventory::setCurrentValue(::Ifc4x2::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x2::IfcCostValue* Ifc4x2::IfcInventory::OriginalValue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x2::IfcCostValue>(true); }
@@ -15687,7 +15687,7 @@ Ifc4x2::IfcIrregularTimeSeriesValue::IfcIrregularTimeSeriesValue(std::string v1_
 
 // Function implementations for IfcJunctionBox
 boost::optional< ::Ifc4x2::IfcJunctionBoxTypeEnum::Value > Ifc4x2::IfcJunctionBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcJunctionBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x2::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcJunctionBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x2::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcJunctionBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcJunctionBox::declaration() const { return *IFC4X2_IfcJunctionBox_type; }
@@ -15709,15 +15709,15 @@ Ifc4x2::IfcJunctionBoxType::IfcJunctionBoxType(std::string v1_GlobalId, ::Ifc4x2
 double Ifc4x2::IfcLShapeProfileDef::Depth() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcLShapeProfileDef::setDepth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcLShapeProfileDef::Width() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 double Ifc4x2::IfcLShapeProfileDef::Thickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x2::IfcLShapeProfileDef::setThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcLShapeProfileDef::FilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcLShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcLShapeProfileDef::LegSlope() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcLShapeProfileDef::declaration() const { return *IFC4X2_IfcLShapeProfileDef_type; }
@@ -15727,7 +15727,7 @@ Ifc4x2::IfcLShapeProfileDef::IfcLShapeProfileDef(::Ifc4x2::IfcProfileTypeEnum::V
 
 // Function implementations for IfcLaborResource
 boost::optional< ::Ifc4x2::IfcLaborResourceTypeEnum::Value > Ifc4x2::IfcLaborResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcLaborResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcLaborResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcLaborResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcLaborResource::declaration() const { return *IFC4X2_IfcLaborResource_type; }
@@ -15759,7 +15759,7 @@ Ifc4x2::IfcLagTime::IfcLagTime(boost::optional< std::string > v1_Name, boost::op
 
 // Function implementations for IfcLamp
 boost::optional< ::Ifc4x2::IfcLampTypeEnum::Value > Ifc4x2::IfcLamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcLampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x2::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcLampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x2::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcLampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcLamp::declaration() const { return *IFC4X2_IfcLamp_type; }
@@ -15781,15 +15781,15 @@ Ifc4x2::IfcLampType::IfcLampType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHist
 std::string Ifc4x2::IfcLibraryInformation::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcLibraryInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcLibraryInformation::Version() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x2::IfcActorSelect* Ifc4x2::IfcLibraryInformation::Publisher() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x2::IfcActorSelect>(true); }
 void Ifc4x2::IfcLibraryInformation::setPublisher(::Ifc4x2::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x2::IfcLibraryInformation::VersionDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcLibraryInformation::Location() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcLibraryInformation::Description() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x2::IfcRelAssociatesLibrary::list::ptr Ifc4x2::IfcLibraryInformation::LibraryInfoForObjects() const { return data_->getInverse(IFC4X2_IfcRelAssociatesLibrary_type, 5)->as<IfcRelAssociatesLibrary>(); }
 ::Ifc4x2::IfcLibraryReference::list::ptr Ifc4x2::IfcLibraryInformation::HasLibraryReferences() const { return data_->getInverse(IFC4X2_IfcLibraryReference_type, 5)->as<IfcLibraryReference>(); }
@@ -15801,9 +15801,9 @@ Ifc4x2::IfcLibraryInformation::IfcLibraryInformation(std::string v1_Name, boost:
 
 // Function implementations for IfcLibraryReference
 boost::optional< std::string > Ifc4x2::IfcLibraryReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcLibraryReference::Language() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x2::IfcLibraryInformation* Ifc4x2::IfcLibraryReference::ReferencedLibrary() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x2::IfcLibraryInformation>(true); }
 void Ifc4x2::IfcLibraryReference::setReferencedLibrary(::Ifc4x2::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -15830,7 +15830,7 @@ Ifc4x2::IfcLightDistributionData::IfcLightDistributionData(double v1_MainPlaneAn
 
 // Function implementations for IfcLightFixture
 boost::optional< ::Ifc4x2::IfcLightFixtureTypeEnum::Value > Ifc4x2::IfcLightFixture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcLightFixtureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x2::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcLightFixtureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x2::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcLightFixtureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcLightFixture::declaration() const { return *IFC4X2_IfcLightFixture_type; }
@@ -15862,13 +15862,13 @@ Ifc4x2::IfcLightIntensityDistribution::IfcLightIntensityDistribution(::Ifc4x2::I
 
 // Function implementations for IfcLightSource
 boost::optional< std::string > Ifc4x2::IfcLightSource::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x2::IfcColourRgb* Ifc4x2::IfcLightSource::LightColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x2::IfcColourRgb>(true); }
 void Ifc4x2::IfcLightSource::setLightColour(::Ifc4x2::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcLightSource::AmbientIntensity() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcLightSource::Intensity() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcLightSource::declaration() const { return *IFC4X2_IfcLightSource_type; }
@@ -15936,7 +15936,7 @@ Ifc4x2::IfcLightSourcePositional::IfcLightSourcePositional(boost::optional< std:
 ::Ifc4x2::IfcDirection* Ifc4x2::IfcLightSourceSpot::Orientation() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x2::IfcDirection>(true); }
 void Ifc4x2::IfcLightSourceSpot::setOrientation(::Ifc4x2::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcLightSourceSpot::ConcentrationExponent() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 double Ifc4x2::IfcLightSourceSpot::SpreadAngle() const {  double v = *data_->getArgument(11); return v; }
 void Ifc4x2::IfcLightSourceSpot::setSpreadAngle(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 double Ifc4x2::IfcLightSourceSpot::BeamWidthAngle() const {  double v = *data_->getArgument(12); return v; }
@@ -16030,11 +16030,11 @@ void Ifc4x2::IfcMapConversion::setNorthings(double v) { {IfcWrite::IfcWriteArgum
 double Ifc4x2::IfcMapConversion::OrthogonalHeight() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x2::IfcMapConversion::setOrthogonalHeight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x2::IfcMapConversion::XAxisAbscissa() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcMapConversion::XAxisOrdinate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcMapConversion::Scale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMapConversion::declaration() const { return *IFC4X2_IfcMapConversion_type; }
@@ -16058,9 +16058,9 @@ Ifc4x2::IfcMappedItem::IfcMappedItem(::Ifc4x2::IfcRepresentationMap* v1_MappingS
 std::string Ifc4x2::IfcMaterial::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcMaterial::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterial::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterial::Category() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x2::IfcMaterialDefinitionRepresentation::list::ptr Ifc4x2::IfcMaterial::HasRepresentation() const { return data_->getInverse(IFC4X2_IfcMaterialDefinitionRepresentation_type, 3)->as<IfcMaterialDefinitionRepresentation>(); }
 ::Ifc4x2::IfcMaterialRelationship::list::ptr Ifc4x2::IfcMaterial::IsRelatedWith() const { return data_->getInverse(IFC4X2_IfcMaterialRelationship_type, 3)->as<IfcMaterialRelationship>(); }
@@ -16085,15 +16085,15 @@ Ifc4x2::IfcMaterialClassificationRelationship::IfcMaterialClassificationRelation
 
 // Function implementations for IfcMaterialConstituent
 boost::optional< std::string > Ifc4x2::IfcMaterialConstituent::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialConstituent::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x2::IfcMaterial* Ifc4x2::IfcMaterialConstituent::Material() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x2::IfcMaterial>(true); }
 void Ifc4x2::IfcMaterialConstituent::setMaterial(::Ifc4x2::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcMaterialConstituent::Fraction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialConstituent::Category() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x2::IfcMaterialConstituentSet::list::ptr Ifc4x2::IfcMaterialConstituent::ToMaterialConstituentSet() const { return data_->getInverse(IFC4X2_IfcMaterialConstituentSet_type, 2)->as<IfcMaterialConstituentSet>(); }
 
@@ -16104,11 +16104,11 @@ Ifc4x2::IfcMaterialConstituent::IfcMaterialConstituent(boost::optional< std::str
 
 // Function implementations for IfcMaterialConstituentSet
 boost::optional< std::string > Ifc4x2::IfcMaterialConstituentSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialConstituentSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcMaterialConstituent >::ptr > Ifc4x2::IfcMaterialConstituentSet::MaterialConstituents() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x2::IfcMaterialConstituent >(); }
-void Ifc4x2::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x2::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x2::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x2::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMaterialConstituentSet::declaration() const { return *IFC4X2_IfcMaterialConstituentSet_type; }
@@ -16143,15 +16143,15 @@ void Ifc4x2::IfcMaterialLayer::setMaterial(::Ifc4x2::IfcMaterial* v) { {IfcWrite
 double Ifc4x2::IfcMaterialLayer::LayerThickness() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcMaterialLayer::setLayerThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< boost::logic::tribool > Ifc4x2::IfcMaterialLayer::IsVentilated() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } boost::logic::tribool v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialLayer::Name() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialLayer::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialLayer::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x2::IfcMaterialLayer::Priority() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x2::IfcMaterialLayerSet::list::ptr Ifc4x2::IfcMaterialLayer::ToMaterialLayerSet() const { return data_->getInverse(IFC4X2_IfcMaterialLayerSet_type, 0)->as<IfcMaterialLayerSet>(); }
 
@@ -16164,9 +16164,9 @@ Ifc4x2::IfcMaterialLayer::IfcMaterialLayer(::Ifc4x2::IfcMaterial* v1_Material, d
 aggregate_of< ::Ifc4x2::IfcMaterialLayer >::ptr Ifc4x2::IfcMaterialLayerSet::MaterialLayers() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x2::IfcMaterialLayer >(); }
 void Ifc4x2::IfcMaterialLayerSet::setMaterialLayers(aggregate_of< ::Ifc4x2::IfcMaterialLayer >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialLayerSet::LayerSetName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialLayerSet::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMaterialLayerSet::declaration() const { return *IFC4X2_IfcMaterialLayerSet_type; }
@@ -16184,7 +16184,7 @@ void Ifc4x2::IfcMaterialLayerSetUsage::setDirectionSense(::Ifc4x2::IfcDirectionS
 double Ifc4x2::IfcMaterialLayerSetUsage::OffsetFromReferenceLine() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcMaterialLayerSetUsage::setOffsetFromReferenceLine(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcMaterialLayerSetUsage::ReferenceExtent() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMaterialLayerSetUsage::declaration() const { return *IFC4X2_IfcMaterialLayerSetUsage_type; }
@@ -16216,17 +16216,17 @@ Ifc4x2::IfcMaterialList::IfcMaterialList(aggregate_of< ::Ifc4x2::IfcMaterial >::
 
 // Function implementations for IfcMaterialProfile
 boost::optional< std::string > Ifc4x2::IfcMaterialProfile::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialProfile::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x2::IfcMaterial* Ifc4x2::IfcMaterialProfile::Material() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x2::IfcMaterial>(true); }
 void Ifc4x2::IfcMaterialProfile::setMaterial(::Ifc4x2::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcProfileDef* Ifc4x2::IfcMaterialProfile::Profile() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcProfileDef>(true); }
 void Ifc4x2::IfcMaterialProfile::setProfile(::Ifc4x2::IfcProfileDef* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x2::IfcMaterialProfile::Priority() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialProfile::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x2::IfcMaterialProfileSet::list::ptr Ifc4x2::IfcMaterialProfile::ToMaterialProfileSet() const { return data_->getInverse(IFC4X2_IfcMaterialProfileSet_type, 2)->as<IfcMaterialProfileSet>(); }
 
@@ -16237,9 +16237,9 @@ Ifc4x2::IfcMaterialProfile::IfcMaterialProfile(boost::optional< std::string > v1
 
 // Function implementations for IfcMaterialProfileSet
 boost::optional< std::string > Ifc4x2::IfcMaterialProfileSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialProfileSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x2::IfcMaterialProfile >::ptr Ifc4x2::IfcMaterialProfileSet::MaterialProfiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x2::IfcMaterialProfile >(); }
 void Ifc4x2::IfcMaterialProfileSet::setMaterialProfiles(aggregate_of< ::Ifc4x2::IfcMaterialProfile >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcCompositeProfileDef* Ifc4x2::IfcMaterialProfileSet::CompositeProfile() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcCompositeProfileDef>(true); }
@@ -16255,9 +16255,9 @@ Ifc4x2::IfcMaterialProfileSet::IfcMaterialProfileSet(boost::optional< std::strin
 ::Ifc4x2::IfcMaterialProfileSet* Ifc4x2::IfcMaterialProfileSetUsage::ForProfileSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x2::IfcMaterialProfileSet>(true); }
 void Ifc4x2::IfcMaterialProfileSetUsage::setForProfileSet(::Ifc4x2::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< int > Ifc4x2::IfcMaterialProfileSetUsage::CardinalPoint() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } int v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcMaterialProfileSetUsage::ReferenceExtent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMaterialProfileSetUsage::declaration() const { return *IFC4X2_IfcMaterialProfileSetUsage_type; }
@@ -16269,7 +16269,7 @@ Ifc4x2::IfcMaterialProfileSetUsage::IfcMaterialProfileSetUsage(::Ifc4x2::IfcMate
 ::Ifc4x2::IfcMaterialProfileSet* Ifc4x2::IfcMaterialProfileSetUsageTapering::ForProfileEndSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcMaterialProfileSet>(true); }
 void Ifc4x2::IfcMaterialProfileSetUsageTapering::setForProfileEndSet(::Ifc4x2::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x2::IfcMaterialProfileSetUsageTapering::CardinalEndPoint() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMaterialProfileSetUsageTapering::declaration() const { return *IFC4X2_IfcMaterialProfileSetUsageTapering_type; }
@@ -16303,7 +16303,7 @@ void Ifc4x2::IfcMaterialRelationship::setRelatingMaterial(::Ifc4x2::IfcMaterial*
 aggregate_of< ::Ifc4x2::IfcMaterial >::ptr Ifc4x2::IfcMaterialRelationship::RelatedMaterials() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x2::IfcMaterial >(); }
 void Ifc4x2::IfcMaterialRelationship::setRelatedMaterials(aggregate_of< ::Ifc4x2::IfcMaterial >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMaterialRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMaterialRelationship::declaration() const { return *IFC4X2_IfcMaterialRelationship_type; }
@@ -16334,11 +16334,11 @@ Ifc4x2::IfcMeasureWithUnit::IfcMeasureWithUnit(::Ifc4x2::IfcValue* v1_ValueCompo
 
 // Function implementations for IfcMechanicalFastener
 boost::optional< double > Ifc4x2::IfcMechanicalFastener::NominalDiameter() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x2::IfcMechanicalFastener::NominalLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x2::IfcMechanicalFastenerTypeEnum::Value > Ifc4x2::IfcMechanicalFastener::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x2::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcMechanicalFastenerTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x2::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcMechanicalFastenerTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMechanicalFastener::declaration() const { return *IFC4X2_IfcMechanicalFastener_type; }
@@ -16350,9 +16350,9 @@ Ifc4x2::IfcMechanicalFastener::IfcMechanicalFastener(std::string v1_GlobalId, ::
 ::Ifc4x2::IfcMechanicalFastenerTypeEnum::Value Ifc4x2::IfcMechanicalFastenerType::PredefinedType() const {  return ::Ifc4x2::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x2::IfcMechanicalFastenerType::setPredefinedType(::Ifc4x2::IfcMechanicalFastenerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcMechanicalFastenerTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcMechanicalFastenerType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcMechanicalFastenerType::NominalLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMechanicalFastenerType::declaration() const { return *IFC4X2_IfcMechanicalFastenerType_type; }
@@ -16362,7 +16362,7 @@ Ifc4x2::IfcMechanicalFastenerType::IfcMechanicalFastenerType(std::string v1_Glob
 
 // Function implementations for IfcMedicalDevice
 boost::optional< ::Ifc4x2::IfcMedicalDeviceTypeEnum::Value > Ifc4x2::IfcMedicalDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcMedicalDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcMedicalDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcMedicalDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMedicalDevice::declaration() const { return *IFC4X2_IfcMedicalDevice_type; }
@@ -16382,7 +16382,7 @@ Ifc4x2::IfcMedicalDeviceType::IfcMedicalDeviceType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcMember
 boost::optional< ::Ifc4x2::IfcMemberTypeEnum::Value > Ifc4x2::IfcMember::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcMemberTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcMember::setPredefinedType(boost::optional< ::Ifc4x2::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcMemberTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcMember::setPredefinedType(boost::optional< ::Ifc4x2::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcMemberTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMember::declaration() const { return *IFC4X2_IfcMember_type; }
@@ -16412,7 +16412,7 @@ Ifc4x2::IfcMemberType::IfcMemberType(std::string v1_GlobalId, ::Ifc4x2::IfcOwner
 ::Ifc4x2::IfcBenchmarkEnum::Value Ifc4x2::IfcMetric::Benchmark() const {  return ::Ifc4x2::IfcBenchmarkEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x2::IfcMetric::setBenchmark(::Ifc4x2::IfcBenchmarkEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcBenchmarkEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcMetric::ValueSource() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x2::IfcMetricValueSelect* Ifc4x2::IfcMetric::DataValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x2::IfcMetricValueSelect>(true); }
 void Ifc4x2::IfcMetric::setDataValue(::Ifc4x2::IfcMetricValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x2::IfcReference* Ifc4x2::IfcMetric::ReferencePath() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x2::IfcReference>(true); }
@@ -16444,7 +16444,7 @@ Ifc4x2::IfcMonetaryUnit::IfcMonetaryUnit(std::string v1_Currency) : IfcUtil::Ifc
 
 // Function implementations for IfcMotorConnection
 boost::optional< ::Ifc4x2::IfcMotorConnectionTypeEnum::Value > Ifc4x2::IfcMotorConnection::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcMotorConnectionTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x2::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcMotorConnectionTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x2::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcMotorConnectionTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcMotorConnection::declaration() const { return *IFC4X2_IfcMotorConnection_type; }
@@ -16476,7 +16476,7 @@ Ifc4x2::IfcNamedUnit::IfcNamedUnit(::Ifc4x2::IfcDimensionalExponents* v1_Dimensi
 
 // Function implementations for IfcObject
 boost::optional< std::string > Ifc4x2::IfcObject::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x2::IfcRelDefinesByObject::list::ptr Ifc4x2::IfcObject::IsDeclaredBy() const { return data_->getInverse(IFC4X2_IfcRelDefinesByObject_type, 4)->as<IfcRelDefinesByObject>(); }
 ::Ifc4x2::IfcRelDefinesByObject::list::ptr Ifc4x2::IfcObject::Declares() const { return data_->getInverse(IFC4X2_IfcRelDefinesByObject_type, 5)->as<IfcRelDefinesByObject>(); }
@@ -16516,13 +16516,13 @@ Ifc4x2::IfcObjectPlacement::IfcObjectPlacement(::Ifc4x2::IfcObjectPlacement* v1_
 
 // Function implementations for IfcObjective
 boost::optional< aggregate_of< ::Ifc4x2::IfcConstraint >::ptr > Ifc4x2::IfcObjective::BenchmarkValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x2::IfcConstraint >(); }
-void Ifc4x2::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x2::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x2::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x2::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x2::IfcLogicalOperatorEnum::Value > Ifc4x2::IfcObjective::LogicalAggregator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcLogicalOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x2::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcLogicalOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x2::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcLogicalOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 ::Ifc4x2::IfcObjectiveEnum::Value Ifc4x2::IfcObjective::ObjectiveQualifier() const {  return ::Ifc4x2::IfcObjectiveEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x2::IfcObjective::setObjectiveQualifier(::Ifc4x2::IfcObjectiveEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcObjectiveEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x2::IfcObjective::UserDefinedQualifier() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcObjective::declaration() const { return *IFC4X2_IfcObjective_type; }
@@ -16532,7 +16532,7 @@ Ifc4x2::IfcObjective::IfcObjective(std::string v1_Name, boost::optional< std::st
 
 // Function implementations for IfcOccupant
 boost::optional< ::Ifc4x2::IfcOccupantTypeEnum::Value > Ifc4x2::IfcOccupant::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x2::IfcOccupantTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x2::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x2::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcOccupantTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x2::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x2::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcOccupantTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcOccupant::declaration() const { return *IFC4X2_IfcOccupant_type; }
@@ -16580,7 +16580,7 @@ Ifc4x2::IfcOffsetCurve3D::IfcOffsetCurve3D(::Ifc4x2::IfcCurve* v1_BasisCurve, do
 aggregate_of< ::Ifc4x2::IfcDistanceExpression >::ptr Ifc4x2::IfcOffsetCurveByDistances::OffsetValues() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x2::IfcDistanceExpression >(); }
 void Ifc4x2::IfcOffsetCurveByDistances::setOffsetValues(aggregate_of< ::Ifc4x2::IfcDistanceExpression >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcOffsetCurveByDistances::Tag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcOffsetCurveByDistances::declaration() const { return *IFC4X2_IfcOffsetCurveByDistances_type; }
@@ -16598,7 +16598,7 @@ Ifc4x2::IfcOpenShell::IfcOpenShell(aggregate_of< ::Ifc4x2::IfcFace >::ptr v1_Cfs
 
 // Function implementations for IfcOpeningElement
 boost::optional< ::Ifc4x2::IfcOpeningElementTypeEnum::Value > Ifc4x2::IfcOpeningElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcOpeningElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcOpeningElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcOpeningElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x2::IfcRelFillsElement::list::ptr Ifc4x2::IfcOpeningElement::HasFillings() const { return data_->getInverse(IFC4X2_IfcRelFillsElement_type, 4)->as<IfcRelFillsElement>(); }
 
@@ -16617,15 +16617,15 @@ Ifc4x2::IfcOpeningStandardCase::IfcOpeningStandardCase(std::string v1_GlobalId,
 
 // Function implementations for IfcOrganization
 boost::optional< std::string > Ifc4x2::IfcOrganization::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 std::string Ifc4x2::IfcOrganization::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcOrganization::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcOrganization::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcActorRole >::ptr > Ifc4x2::IfcOrganization::Roles() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x2::IfcActorRole >(); }
-void Ifc4x2::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(3,attr);} }
+void Ifc4x2::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(3,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcAddress >::ptr > Ifc4x2::IfcOrganization::Addresses() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x2::IfcAddress >(); }
-void Ifc4x2::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x2::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(4,attr);} }
+void Ifc4x2::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x2::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(4,attr);} }
 
 ::Ifc4x2::IfcOrganizationRelationship::list::ptr Ifc4x2::IfcOrganization::IsRelatedBy() const { return data_->getInverse(IFC4X2_IfcOrganizationRelationship_type, 3)->as<IfcOrganizationRelationship>(); }
 ::Ifc4x2::IfcOrganizationRelationship::list::ptr Ifc4x2::IfcOrganization::Relates() const { return data_->getInverse(IFC4X2_IfcOrganizationRelationship_type, 2)->as<IfcOrganizationRelationship>(); }
@@ -16682,7 +16682,7 @@ Ifc4x2::IfcOuterBoundaryCurve::IfcOuterBoundaryCurve(aggregate_of< ::Ifc4x2::Ifc
 
 // Function implementations for IfcOutlet
 boost::optional< ::Ifc4x2::IfcOutletTypeEnum::Value > Ifc4x2::IfcOutlet::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcOutletTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x2::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcOutletTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x2::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcOutletTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcOutlet::declaration() const { return *IFC4X2_IfcOutlet_type; }
@@ -16706,11 +16706,11 @@ void Ifc4x2::IfcOwnerHistory::setOwningUser(::Ifc4x2::IfcPersonAndOrganization*
 ::Ifc4x2::IfcApplication* Ifc4x2::IfcOwnerHistory::OwningApplication() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x2::IfcApplication>(true); }
 void Ifc4x2::IfcOwnerHistory::setOwningApplication(::Ifc4x2::IfcApplication* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x2::IfcStateEnum::Value > Ifc4x2::IfcOwnerHistory::State() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x2::IfcStateEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x2::IfcOwnerHistory::setState(boost::optional< ::Ifc4x2::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcStateEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x2::IfcOwnerHistory::setState(boost::optional< ::Ifc4x2::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcStateEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< ::Ifc4x2::IfcChangeActionEnum::Value > Ifc4x2::IfcOwnerHistory::ChangeAction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x2::IfcChangeActionEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x2::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x2::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcChangeActionEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x2::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x2::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcChangeActionEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x2::IfcOwnerHistory::LastModifiedDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x2::IfcPersonAndOrganization* Ifc4x2::IfcOwnerHistory::LastModifyingUser() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x2::IfcPersonAndOrganization>(true); }
 void Ifc4x2::IfcOwnerHistory::setLastModifyingUser(::Ifc4x2::IfcPersonAndOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x2::IfcApplication* Ifc4x2::IfcOwnerHistory::LastModifyingApplication() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcApplication>(true); }
@@ -16760,7 +16760,7 @@ Ifc4x2::IfcPcurve::IfcPcurve(::Ifc4x2::IfcSurface* v1_BasisSurface, ::Ifc4x2::If
 std::string Ifc4x2::IfcPerformanceHistory::LifeCyclePhase() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x2::IfcPerformanceHistory::setLifeCyclePhase(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x2::IfcPerformanceHistoryTypeEnum::Value > Ifc4x2::IfcPerformanceHistory::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x2::IfcPerformanceHistoryTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x2::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x2::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPerformanceHistoryTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x2::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x2::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPerformanceHistoryTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPerformanceHistory::declaration() const { return *IFC4X2_IfcPerformanceHistory_type; }
@@ -16774,9 +16774,9 @@ void Ifc4x2::IfcPermeableCoveringProperties::setOperationType(::Ifc4x2::IfcPerme
 ::Ifc4x2::IfcWindowPanelPositionEnum::Value Ifc4x2::IfcPermeableCoveringProperties::PanelPosition() const {  return ::Ifc4x2::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x2::IfcPermeableCoveringProperties::setPanelPosition(::Ifc4x2::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcPermeableCoveringProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcPermeableCoveringProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x2::IfcShapeAspect* Ifc4x2::IfcPermeableCoveringProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x2::IfcShapeAspect>(true); }
 void Ifc4x2::IfcPermeableCoveringProperties::setShapeAspectStyle(::Ifc4x2::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -16788,11 +16788,11 @@ Ifc4x2::IfcPermeableCoveringProperties::IfcPermeableCoveringProperties(std::stri
 
 // Function implementations for IfcPermit
 boost::optional< ::Ifc4x2::IfcPermitTypeEnum::Value > Ifc4x2::IfcPermit::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x2::IfcPermitTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x2::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x2::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPermitTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x2::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x2::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPermitTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPermit::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPermit::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPermit::declaration() const { return *IFC4X2_IfcPermit_type; }
@@ -16802,21 +16802,21 @@ Ifc4x2::IfcPermit::IfcPermit(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory*
 
 // Function implementations for IfcPerson
 boost::optional< std::string > Ifc4x2::IfcPerson::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPerson::FamilyName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPerson::GivenName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcPerson::MiddleNames() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcPerson::PrefixTitles() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcPerson::SuffixTitles() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcActorRole >::ptr > Ifc4x2::IfcPerson::Roles() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x2::IfcActorRole >(); }
-void Ifc4x2::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x2::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcAddress >::ptr > Ifc4x2::IfcPerson::Addresses() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x2::IfcAddress >(); }
-void Ifc4x2::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x2::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x2::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x2::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 ::Ifc4x2::IfcPersonAndOrganization::list::ptr Ifc4x2::IfcPerson::EngagedIn() const { return data_->getInverse(IFC4X2_IfcPersonAndOrganization_type, 0)->as<IfcPersonAndOrganization>(); }
 
@@ -16831,7 +16831,7 @@ void Ifc4x2::IfcPersonAndOrganization::setThePerson(::Ifc4x2::IfcPerson* v) { {I
 ::Ifc4x2::IfcOrganization* Ifc4x2::IfcPersonAndOrganization::TheOrganization() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x2::IfcOrganization>(true); }
 void Ifc4x2::IfcPersonAndOrganization::setTheOrganization(::Ifc4x2::IfcOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcActorRole >::ptr > Ifc4x2::IfcPersonAndOrganization::Roles() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x2::IfcActorRole >(); }
-void Ifc4x2::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x2::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPersonAndOrganization::declaration() const { return *IFC4X2_IfcPersonAndOrganization_type; }
@@ -16845,9 +16845,9 @@ void Ifc4x2::IfcPhysicalComplexQuantity::setHasQuantities(aggregate_of< ::Ifc4x2
 std::string Ifc4x2::IfcPhysicalComplexQuantity::Discrimination() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcPhysicalComplexQuantity::setDiscrimination(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPhysicalComplexQuantity::Quality() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPhysicalComplexQuantity::Usage() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPhysicalComplexQuantity::declaration() const { return *IFC4X2_IfcPhysicalComplexQuantity_type; }
@@ -16859,7 +16859,7 @@ Ifc4x2::IfcPhysicalComplexQuantity::IfcPhysicalComplexQuantity(std::string v1_Na
 std::string Ifc4x2::IfcPhysicalQuantity::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcPhysicalQuantity::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPhysicalQuantity::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x2::IfcExternalReferenceRelationship::list::ptr Ifc4x2::IfcPhysicalQuantity::HasExternalReferences() const { return data_->getInverse(IFC4X2_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x2::IfcPhysicalComplexQuantity::list::ptr Ifc4x2::IfcPhysicalQuantity::PartOfComplex() const { return data_->getInverse(IFC4X2_IfcPhysicalComplexQuantity_type, 2)->as<IfcPhysicalComplexQuantity>(); }
@@ -16881,9 +16881,9 @@ Ifc4x2::IfcPhysicalSimpleQuantity::IfcPhysicalSimpleQuantity(std::string v1_Name
 
 // Function implementations for IfcPile
 boost::optional< ::Ifc4x2::IfcPileTypeEnum::Value > Ifc4x2::IfcPile::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcPileTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcPile::setPredefinedType(boost::optional< ::Ifc4x2::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPileTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcPile::setPredefinedType(boost::optional< ::Ifc4x2::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPileTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x2::IfcPileConstructionEnum::Value > Ifc4x2::IfcPile::ConstructionType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x2::IfcPileConstructionEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x2::IfcPile::setConstructionType(boost::optional< ::Ifc4x2::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPileConstructionEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x2::IfcPile::setConstructionType(boost::optional< ::Ifc4x2::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPileConstructionEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPile::declaration() const { return *IFC4X2_IfcPile_type; }
@@ -16903,7 +16903,7 @@ Ifc4x2::IfcPileType::IfcPileType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHist
 
 // Function implementations for IfcPipeFitting
 boost::optional< ::Ifc4x2::IfcPipeFittingTypeEnum::Value > Ifc4x2::IfcPipeFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcPipeFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x2::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPipeFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x2::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPipeFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPipeFitting::declaration() const { return *IFC4X2_IfcPipeFitting_type; }
@@ -16923,7 +16923,7 @@ Ifc4x2::IfcPipeFittingType::IfcPipeFittingType(std::string v1_GlobalId, ::Ifc4x2
 
 // Function implementations for IfcPipeSegment
 boost::optional< ::Ifc4x2::IfcPipeSegmentTypeEnum::Value > Ifc4x2::IfcPipeSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcPipeSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x2::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPipeSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x2::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPipeSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPipeSegment::declaration() const { return *IFC4X2_IfcPipeSegment_type; }
@@ -16999,7 +16999,7 @@ Ifc4x2::IfcPlane::IfcPlane(::Ifc4x2::IfcAxis2Placement3D* v1_Position) : IfcElem
 
 // Function implementations for IfcPlate
 boost::optional< ::Ifc4x2::IfcPlateTypeEnum::Value > Ifc4x2::IfcPlate::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcPlateTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x2::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPlateTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x2::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPlateTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPlate::declaration() const { return *IFC4X2_IfcPlate_type; }
@@ -17083,11 +17083,11 @@ Ifc4x2::IfcPolygonalBoundedHalfSpace::IfcPolygonalBoundedHalfSpace(::Ifc4x2::Ifc
 
 // Function implementations for IfcPolygonalFaceSet
 boost::optional< bool > Ifc4x2::IfcPolygonalFaceSet::Closed() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x2::IfcIndexedPolygonalFace >::ptr Ifc4x2::IfcPolygonalFaceSet::Faces() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x2::IfcIndexedPolygonalFace >(); }
 void Ifc4x2::IfcPolygonalFaceSet::setFaces(aggregate_of< ::Ifc4x2::IfcIndexedPolygonalFace >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x2::IfcPolygonalFaceSet::PnIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPolygonalFaceSet::declaration() const { return *IFC4X2_IfcPolygonalFaceSet_type; }
@@ -17128,19 +17128,19 @@ Ifc4x2::IfcPositioningElement::IfcPositioningElement(std::string v1_GlobalId, ::
 
 // Function implementations for IfcPostalAddress
 boost::optional< std::string > Ifc4x2::IfcPostalAddress::InternalLocation() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcPostalAddress::AddressLines() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPostalAddress::PostalBox() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPostalAddress::Town() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPostalAddress::Region() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPostalAddress::PostalCode() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPostalAddress::Country() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPostalAddress::declaration() const { return *IFC4X2_IfcPostalAddress_type; }
@@ -17210,11 +17210,11 @@ Ifc4x2::IfcPresentationItem::IfcPresentationItem() : IfcUtil::IfcBaseEntity() {d
 std::string Ifc4x2::IfcPresentationLayerAssignment::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcPresentationLayerAssignment::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPresentationLayerAssignment::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of_instance::ptr Ifc4x2::IfcPresentationLayerAssignment::AssignedItems() const {  aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
 void Ifc4x2::IfcPresentationLayerAssignment::setAssignedItems(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPresentationLayerAssignment::Identifier() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPresentationLayerAssignment::declaration() const { return *IFC4X2_IfcPresentationLayerAssignment_type; }
@@ -17240,7 +17240,7 @@ Ifc4x2::IfcPresentationLayerWithStyle::IfcPresentationLayerWithStyle(std::string
 
 // Function implementations for IfcPresentationStyle
 boost::optional< std::string > Ifc4x2::IfcPresentationStyle::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPresentationStyle::declaration() const { return *IFC4X2_IfcPresentationStyle_type; }
@@ -17260,7 +17260,7 @@ Ifc4x2::IfcPresentationStyleAssignment::IfcPresentationStyleAssignment(aggregate
 
 // Function implementations for IfcProcedure
 boost::optional< ::Ifc4x2::IfcProcedureTypeEnum::Value > Ifc4x2::IfcProcedure::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x2::IfcProcedureTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x2::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x2::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProcedureTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x2::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x2::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProcedureTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcProcedure::declaration() const { return *IFC4X2_IfcProcedure_type; }
@@ -17280,9 +17280,9 @@ Ifc4x2::IfcProcedureType::IfcProcedureType(std::string v1_GlobalId, ::Ifc4x2::If
 
 // Function implementations for IfcProcess
 boost::optional< std::string > Ifc4x2::IfcProcess::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcProcess::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x2::IfcRelSequence::list::ptr Ifc4x2::IfcProcess::IsPredecessorTo() const { return data_->getInverse(IFC4X2_IfcRelSequence_type, 4)->as<IfcRelSequence>(); }
 ::Ifc4x2::IfcRelSequence::list::ptr Ifc4x2::IfcProcess::IsSuccessorFrom() const { return data_->getInverse(IFC4X2_IfcRelSequence_type, 5)->as<IfcRelSequence>(); }
@@ -17319,9 +17319,9 @@ Ifc4x2::IfcProductDefinitionShape::IfcProductDefinitionShape(boost::optional< st
 
 // Function implementations for IfcProductRepresentation
 boost::optional< std::string > Ifc4x2::IfcProductRepresentation::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcProductRepresentation::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x2::IfcRepresentation >::ptr Ifc4x2::IfcProductRepresentation::Representations() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x2::IfcRepresentation >(); }
 void Ifc4x2::IfcProductRepresentation::setRepresentations(aggregate_of< ::Ifc4x2::IfcRepresentation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -17335,7 +17335,7 @@ Ifc4x2::IfcProductRepresentation::IfcProductRepresentation(boost::optional< std:
 ::Ifc4x2::IfcProfileTypeEnum::Value Ifc4x2::IfcProfileDef::ProfileType() const {  return ::Ifc4x2::IfcProfileTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x2::IfcProfileDef::setProfileType(::Ifc4x2::IfcProfileTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcProfileTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcProfileDef::ProfileName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x2::IfcExternalReferenceRelationship::list::ptr Ifc4x2::IfcProfileDef::HasExternalReference() const { return data_->getInverse(IFC4X2_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x2::IfcProfileProperties::list::ptr Ifc4x2::IfcProfileDef::HasProperties() const { return data_->getInverse(IFC4X2_IfcProfileProperties_type, 3)->as<IfcProfileProperties>(); }
@@ -17373,11 +17373,11 @@ Ifc4x2::IfcProjectLibrary::IfcProjectLibrary(std::string v1_GlobalId, ::Ifc4x2::
 
 // Function implementations for IfcProjectOrder
 boost::optional< ::Ifc4x2::IfcProjectOrderTypeEnum::Value > Ifc4x2::IfcProjectOrder::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x2::IfcProjectOrderTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x2::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x2::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProjectOrderTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x2::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x2::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProjectOrderTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcProjectOrder::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcProjectOrder::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcProjectOrder::declaration() const { return *IFC4X2_IfcProjectOrder_type; }
@@ -17387,9 +17387,9 @@ Ifc4x2::IfcProjectOrder::IfcProjectOrder(std::string v1_GlobalId, ::Ifc4x2::IfcO
 
 // Function implementations for IfcProjectedCRS
 boost::optional< std::string > Ifc4x2::IfcProjectedCRS::MapProjection() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcProjectedCRS::MapZone() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x2::IfcNamedUnit* Ifc4x2::IfcProjectedCRS::MapUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcNamedUnit>(true); }
 void Ifc4x2::IfcProjectedCRS::setMapUnit(::Ifc4x2::IfcNamedUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -17401,7 +17401,7 @@ Ifc4x2::IfcProjectedCRS::IfcProjectedCRS(std::string v1_Name, boost::optional< s
 
 // Function implementations for IfcProjectionElement
 boost::optional< ::Ifc4x2::IfcProjectionElementTypeEnum::Value > Ifc4x2::IfcProjectionElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcProjectionElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProjectionElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProjectionElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcProjectionElement::declaration() const { return *IFC4X2_IfcProjectionElement_type; }
@@ -17413,7 +17413,7 @@ Ifc4x2::IfcProjectionElement::IfcProjectionElement(std::string v1_GlobalId, ::If
 std::string Ifc4x2::IfcProperty::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcProperty::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcProperty::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x2::IfcPropertySet::list::ptr Ifc4x2::IfcProperty::PartOfPset() const { return data_->getInverse(IFC4X2_IfcPropertySet_type, 4)->as<IfcPropertySet>(); }
 ::Ifc4x2::IfcPropertyDependencyRelationship::list::ptr Ifc4x2::IfcProperty::PropertyForDependance() const { return data_->getInverse(IFC4X2_IfcPropertyDependencyRelationship_type, 2)->as<IfcPropertyDependencyRelationship>(); }
@@ -17468,7 +17468,7 @@ void Ifc4x2::IfcPropertyDependencyRelationship::setDependingProperty(::Ifc4x2::I
 ::Ifc4x2::IfcProperty* Ifc4x2::IfcPropertyDependencyRelationship::DependantProperty() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcProperty>(true); }
 void Ifc4x2::IfcPropertyDependencyRelationship::setDependantProperty(::Ifc4x2::IfcProperty* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPropertyDependencyRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPropertyDependencyRelationship::declaration() const { return *IFC4X2_IfcPropertyDependencyRelationship_type; }
@@ -17478,7 +17478,7 @@ Ifc4x2::IfcPropertyDependencyRelationship::IfcPropertyDependencyRelationship(boo
 
 // Function implementations for IfcPropertyEnumeratedValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x2::IfcPropertyEnumeratedValue::EnumerationValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcPropertyEnumeration* Ifc4x2::IfcPropertyEnumeratedValue::EnumerationReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcPropertyEnumeration>(true); }
 void Ifc4x2::IfcPropertyEnumeratedValue::setEnumerationReference(::Ifc4x2::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -17504,7 +17504,7 @@ Ifc4x2::IfcPropertyEnumeration::IfcPropertyEnumeration(std::string v1_Name, aggr
 
 // Function implementations for IfcPropertyListValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x2::IfcPropertyListValue::ListValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcUnit* Ifc4x2::IfcPropertyListValue::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcUnit>(true); }
 void Ifc4x2::IfcPropertyListValue::setUnit(::Ifc4x2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -17516,7 +17516,7 @@ Ifc4x2::IfcPropertyListValue::IfcPropertyListValue(std::string v1_Name, boost::o
 
 // Function implementations for IfcPropertyReferenceValue
 boost::optional< std::string > Ifc4x2::IfcPropertyReferenceValue::UsageName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcObjectReferenceSelect* Ifc4x2::IfcPropertyReferenceValue::PropertyReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcObjectReferenceSelect>(true); }
 void Ifc4x2::IfcPropertyReferenceValue::setPropertyReference(::Ifc4x2::IfcObjectReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -17549,9 +17549,9 @@ Ifc4x2::IfcPropertySetDefinition::IfcPropertySetDefinition(std::string v1_Global
 
 // Function implementations for IfcPropertySetTemplate
 boost::optional< ::Ifc4x2::IfcPropertySetTemplateTypeEnum::Value > Ifc4x2::IfcPropertySetTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x2::IfcPropertySetTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x2::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x2::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPropertySetTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x2::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x2::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPropertySetTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPropertySetTemplate::ApplicableEntity() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 aggregate_of< ::Ifc4x2::IfcPropertyTemplate >::ptr Ifc4x2::IfcPropertySetTemplate::HasPropertyTemplates() const {  aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x2::IfcPropertyTemplate >(); }
 void Ifc4x2::IfcPropertySetTemplate::setHasPropertyTemplates(aggregate_of< ::Ifc4x2::IfcPropertyTemplate >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(6,attr);} }
 
@@ -17576,17 +17576,17 @@ Ifc4x2::IfcPropertySingleValue::IfcPropertySingleValue(std::string v1_Name, boos
 
 // Function implementations for IfcPropertyTableValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x2::IfcPropertyTableValue::DefiningValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x2::IfcPropertyTableValue::DefinedValues() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcPropertyTableValue::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x2::IfcUnit* Ifc4x2::IfcPropertyTableValue::DefiningUnit() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x2::IfcUnit>(true); }
 void Ifc4x2::IfcPropertyTableValue::setDefiningUnit(::Ifc4x2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x2::IfcUnit* Ifc4x2::IfcPropertyTableValue::DefinedUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcUnit>(true); }
 void Ifc4x2::IfcPropertyTableValue::setDefinedUnit(::Ifc4x2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x2::IfcCurveInterpolationEnum::Value > Ifc4x2::IfcPropertyTableValue::CurveInterpolation() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x2::IfcCurveInterpolationEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x2::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x2::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCurveInterpolationEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x2::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x2::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcCurveInterpolationEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPropertyTableValue::declaration() const { return *IFC4X2_IfcPropertyTableValue_type; }
@@ -17614,7 +17614,7 @@ Ifc4x2::IfcPropertyTemplateDefinition::IfcPropertyTemplateDefinition(std::string
 
 // Function implementations for IfcProtectiveDevice
 boost::optional< ::Ifc4x2::IfcProtectiveDeviceTypeEnum::Value > Ifc4x2::IfcProtectiveDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcProtectiveDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProtectiveDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProtectiveDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcProtectiveDevice::declaration() const { return *IFC4X2_IfcProtectiveDevice_type; }
@@ -17624,7 +17624,7 @@ Ifc4x2::IfcProtectiveDevice::IfcProtectiveDevice(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcProtectiveDeviceTrippingUnit
 boost::optional< ::Ifc4x2::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > Ifc4x2::IfcProtectiveDeviceTrippingUnit::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcProtectiveDeviceTrippingUnitTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x2::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x2::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcProtectiveDeviceTrippingUnit::declaration() const { return *IFC4X2_IfcProtectiveDeviceTrippingUnit_type; }
@@ -17656,7 +17656,7 @@ Ifc4x2::IfcProtectiveDeviceType::IfcProtectiveDeviceType(std::string v1_GlobalId
 ::Ifc4x2::IfcObjectTypeEnum::Value Ifc4x2::IfcProxy::ProxyType() const {  return ::Ifc4x2::IfcObjectTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x2::IfcProxy::setProxyType(::Ifc4x2::IfcObjectTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcObjectTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcProxy::Tag() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcProxy::declaration() const { return *IFC4X2_IfcProxy_type; }
@@ -17666,7 +17666,7 @@ Ifc4x2::IfcProxy::IfcProxy(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory* v
 
 // Function implementations for IfcPump
 boost::optional< ::Ifc4x2::IfcPumpTypeEnum::Value > Ifc4x2::IfcPump::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcPumpTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcPump::setPredefinedType(boost::optional< ::Ifc4x2::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPumpTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcPump::setPredefinedType(boost::optional< ::Ifc4x2::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcPumpTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcPump::declaration() const { return *IFC4X2_IfcPump_type; }
@@ -17688,7 +17688,7 @@ Ifc4x2::IfcPumpType::IfcPumpType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHist
 double Ifc4x2::IfcQuantityArea::AreaValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcQuantityArea::setAreaValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcQuantityArea::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcQuantityArea::declaration() const { return *IFC4X2_IfcQuantityArea_type; }
@@ -17700,7 +17700,7 @@ Ifc4x2::IfcQuantityArea::IfcQuantityArea(std::string v1_Name, boost::optional< s
 double Ifc4x2::IfcQuantityCount::CountValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcQuantityCount::setCountValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcQuantityCount::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcQuantityCount::declaration() const { return *IFC4X2_IfcQuantityCount_type; }
@@ -17712,7 +17712,7 @@ Ifc4x2::IfcQuantityCount::IfcQuantityCount(std::string v1_Name, boost::optional<
 double Ifc4x2::IfcQuantityLength::LengthValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcQuantityLength::setLengthValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcQuantityLength::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcQuantityLength::declaration() const { return *IFC4X2_IfcQuantityLength_type; }
@@ -17732,7 +17732,7 @@ Ifc4x2::IfcQuantitySet::IfcQuantitySet(std::string v1_GlobalId, ::Ifc4x2::IfcOwn
 double Ifc4x2::IfcQuantityTime::TimeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcQuantityTime::setTimeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcQuantityTime::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcQuantityTime::declaration() const { return *IFC4X2_IfcQuantityTime_type; }
@@ -17744,7 +17744,7 @@ Ifc4x2::IfcQuantityTime::IfcQuantityTime(std::string v1_Name, boost::optional< s
 double Ifc4x2::IfcQuantityVolume::VolumeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcQuantityVolume::setVolumeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcQuantityVolume::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcQuantityVolume::declaration() const { return *IFC4X2_IfcQuantityVolume_type; }
@@ -17756,7 +17756,7 @@ Ifc4x2::IfcQuantityVolume::IfcQuantityVolume(std::string v1_Name, boost::optiona
 double Ifc4x2::IfcQuantityWeight::WeightValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcQuantityWeight::setWeightValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcQuantityWeight::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcQuantityWeight::declaration() const { return *IFC4X2_IfcQuantityWeight_type; }
@@ -17766,7 +17766,7 @@ Ifc4x2::IfcQuantityWeight::IfcQuantityWeight(std::string v1_Name, boost::optiona
 
 // Function implementations for IfcRailing
 boost::optional< ::Ifc4x2::IfcRailingTypeEnum::Value > Ifc4x2::IfcRailing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcRailingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x2::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcRailingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x2::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcRailingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcRailing::declaration() const { return *IFC4X2_IfcRailing_type; }
@@ -17786,7 +17786,7 @@ Ifc4x2::IfcRailingType::IfcRailingType(std::string v1_GlobalId, ::Ifc4x2::IfcOwn
 
 // Function implementations for IfcRamp
 boost::optional< ::Ifc4x2::IfcRampTypeEnum::Value > Ifc4x2::IfcRamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcRampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x2::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcRampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x2::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcRampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcRamp::declaration() const { return *IFC4X2_IfcRamp_type; }
@@ -17796,7 +17796,7 @@ Ifc4x2::IfcRamp::IfcRamp(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory* v2_
 
 // Function implementations for IfcRampFlight
 boost::optional< ::Ifc4x2::IfcRampFlightTypeEnum::Value > Ifc4x2::IfcRampFlight::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcRampFlightTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x2::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcRampFlightTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x2::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcRampFlightTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcRampFlight::declaration() const { return *IFC4X2_IfcRampFlight_type; }
@@ -17848,9 +17848,9 @@ Ifc4x2::IfcRationalBSplineSurfaceWithKnots::IfcRationalBSplineSurfaceWithKnots(i
 double Ifc4x2::IfcRectangleHollowProfileDef::WallThickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x2::IfcRectangleHollowProfileDef::setWallThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcRectangleHollowProfileDef::InnerFilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcRectangleHollowProfileDef::OuterFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcRectangleHollowProfileDef::declaration() const { return *IFC4X2_IfcRectangleHollowProfileDef_type; }
@@ -17910,19 +17910,19 @@ Ifc4x2::IfcRectangularTrimmedSurface::IfcRectangularTrimmedSurface(::Ifc4x2::Ifc
 ::Ifc4x2::IfcRecurrenceTypeEnum::Value Ifc4x2::IfcRecurrencePattern::RecurrenceType() const {  return ::Ifc4x2::IfcRecurrenceTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x2::IfcRecurrencePattern::setRecurrenceType(::Ifc4x2::IfcRecurrenceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcRecurrenceTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x2::IfcRecurrencePattern::DayComponent() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x2::IfcRecurrencePattern::WeekdayComponent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x2::IfcRecurrencePattern::MonthComponent() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x2::IfcRecurrencePattern::Position() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< int > Ifc4x2::IfcRecurrencePattern::Interval() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } int v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x2::IfcRecurrencePattern::Occurrences() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcTimePeriod >::ptr > Ifc4x2::IfcRecurrencePattern::TimePeriods() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x2::IfcTimePeriod >(); }
-void Ifc4x2::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x2::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x2::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x2::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcRecurrencePattern::declaration() const { return *IFC4X2_IfcRecurrencePattern_type; }
@@ -17932,13 +17932,13 @@ Ifc4x2::IfcRecurrencePattern::IfcRecurrencePattern(::Ifc4x2::IfcRecurrenceTypeEn
 
 // Function implementations for IfcReference
 boost::optional< std::string > Ifc4x2::IfcReference::TypeIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcReference::AttributeIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcReference::InstanceName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x2::IfcReference::ListPositions() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x2::IfcReference* Ifc4x2::IfcReference::InnerReference() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x2::IfcReference>(true); }
 void Ifc4x2::IfcReference::setInnerReference(::Ifc4x2::IfcReference* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -17950,9 +17950,9 @@ Ifc4x2::IfcReference::IfcReference(boost::optional< std::string > v1_TypeIdentif
 
 // Function implementations for IfcReferent
 boost::optional< ::Ifc4x2::IfcReferentTypeEnum::Value > Ifc4x2::IfcReferent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x2::IfcReferentTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x2::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x2::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReferentTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x2::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x2::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReferentTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcReferent::RestartDistance() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcReferent::declaration() const { return *IFC4X2_IfcReferent_type; }
@@ -17978,13 +17978,13 @@ void Ifc4x2::IfcReinforcementBarProperties::setTotalCrossSectionArea(double v) {
 std::string Ifc4x2::IfcReinforcementBarProperties::SteelGrade() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcReinforcementBarProperties::setSteelGrade(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x2::IfcReinforcingBarSurfaceEnum::Value > Ifc4x2::IfcReinforcementBarProperties::BarSurface() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x2::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x2::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x2::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcementBarProperties::EffectiveDepth() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcementBarProperties::NominalBarDiameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcementBarProperties::BarCount() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcReinforcementBarProperties::declaration() const { return *IFC4X2_IfcReinforcementBarProperties_type; }
@@ -17994,7 +17994,7 @@ Ifc4x2::IfcReinforcementBarProperties::IfcReinforcementBarProperties(double v1_T
 
 // Function implementations for IfcReinforcementDefinitionProperties
 boost::optional< std::string > Ifc4x2::IfcReinforcementDefinitionProperties::DefinitionType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x2::IfcSectionReinforcementProperties >::ptr Ifc4x2::IfcReinforcementDefinitionProperties::ReinforcementSectionDefinitions() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x2::IfcSectionReinforcementProperties >(); }
 void Ifc4x2::IfcReinforcementDefinitionProperties::setReinforcementSectionDefinitions(aggregate_of< ::Ifc4x2::IfcSectionReinforcementProperties >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -18006,15 +18006,15 @@ Ifc4x2::IfcReinforcementDefinitionProperties::IfcReinforcementDefinitionProperti
 
 // Function implementations for IfcReinforcingBar
 boost::optional< double > Ifc4x2::IfcReinforcingBar::NominalDiameter() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingBar::CrossSectionArea() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingBar::BarLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x2::IfcReinforcingBarTypeEnum::Value > Ifc4x2::IfcReinforcingBar::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x2::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x2::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x2::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReinforcingBarTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x2::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x2::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReinforcingBarTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x2::IfcReinforcingBarSurfaceEnum::Value > Ifc4x2::IfcReinforcingBar::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x2::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x2::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x2::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcReinforcingBar::declaration() const { return *IFC4X2_IfcReinforcingBar_type; }
@@ -18026,17 +18026,17 @@ Ifc4x2::IfcReinforcingBar::IfcReinforcingBar(std::string v1_GlobalId, ::Ifc4x2::
 ::Ifc4x2::IfcReinforcingBarTypeEnum::Value Ifc4x2::IfcReinforcingBarType::PredefinedType() const {  return ::Ifc4x2::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x2::IfcReinforcingBarType::setPredefinedType(::Ifc4x2::IfcReinforcingBarTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcReinforcingBarTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingBarType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingBarType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingBarType::BarLength() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x2::IfcReinforcingBarSurfaceEnum::Value > Ifc4x2::IfcReinforcingBarType::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x2::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x2::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x2::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x2::IfcReinforcingBarType::BendingShapeCode() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x2::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x2::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x2::IfcReinforcingBarType::BendingParameters() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(15); return v; }
-void Ifc4x2::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x2::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcReinforcingBarType::declaration() const { return *IFC4X2_IfcReinforcingBarType_type; }
@@ -18046,7 +18046,7 @@ Ifc4x2::IfcReinforcingBarType::IfcReinforcingBarType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcReinforcingElement
 boost::optional< std::string > Ifc4x2::IfcReinforcingElement::SteelGrade() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcReinforcingElement::declaration() const { return *IFC4X2_IfcReinforcingElement_type; }
@@ -18064,23 +18064,23 @@ Ifc4x2::IfcReinforcingElementType::IfcReinforcingElementType(std::string v1_Glob
 
 // Function implementations for IfcReinforcingMesh
 boost::optional< double > Ifc4x2::IfcReinforcingMesh::MeshLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMesh::MeshWidth() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMesh::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMesh::TransverseBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMesh::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x2::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x2::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMesh::TransverseBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x2::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x2::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMesh::LongitudinalBarSpacing() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x2::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x2::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMesh::TransverseBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x2::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x2::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< ::Ifc4x2::IfcReinforcingMeshTypeEnum::Value > Ifc4x2::IfcReinforcingMesh::PredefinedType() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } return ::Ifc4x2::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(17)); }
-void Ifc4x2::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x2::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReinforcingMeshTypeEnum::ToString(*v)));data_->setArgument(17,attr);} }
+void Ifc4x2::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x2::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcReinforcingMeshTypeEnum::ToString(*v)));}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcReinforcingMesh::declaration() const { return *IFC4X2_IfcReinforcingMesh_type; }
@@ -18092,25 +18092,25 @@ Ifc4x2::IfcReinforcingMesh::IfcReinforcingMesh(std::string v1_GlobalId, ::Ifc4x2
 ::Ifc4x2::IfcReinforcingMeshTypeEnum::Value Ifc4x2::IfcReinforcingMeshType::PredefinedType() const {  return ::Ifc4x2::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x2::IfcReinforcingMeshType::setPredefinedType(::Ifc4x2::IfcReinforcingMeshTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcReinforcingMeshTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMeshType::MeshLength() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMeshType::MeshWidth() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMeshType::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMeshType::TransverseBarNominalDiameter() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x2::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x2::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMeshType::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x2::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x2::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMeshType::TransverseBarCrossSectionArea() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x2::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x2::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMeshType::LongitudinalBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x2::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x2::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x2::IfcReinforcingMeshType::TransverseBarSpacing() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x2::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x2::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x2::IfcReinforcingMeshType::BendingShapeCode() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x2::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x2::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x2::IfcReinforcingMeshType::BendingParameters() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(19); return v; }
-void Ifc4x2::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x2::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcReinforcingMeshType::declaration() const { return *IFC4X2_IfcReinforcingMeshType_type; }
@@ -18134,7 +18134,7 @@ Ifc4x2::IfcRelAggregates::IfcRelAggregates(std::string v1_GlobalId, ::Ifc4x2::If
 aggregate_of< ::Ifc4x2::IfcObjectDefinition >::ptr Ifc4x2::IfcRelAssigns::RelatedObjects() const {  aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x2::IfcObjectDefinition >(); }
 void Ifc4x2::IfcRelAssigns::setRelatedObjects(aggregate_of< ::Ifc4x2::IfcObjectDefinition >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x2::IfcObjectTypeEnum::Value > Ifc4x2::IfcRelAssigns::RelatedObjectsType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x2::IfcObjectTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x2::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x2::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcObjectTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x2::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x2::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcObjectTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcRelAssigns::declaration() const { return *IFC4X2_IfcRelAssigns_type; }
@@ -18248,7 +18248,7 @@ Ifc4x2::IfcRelAssociatesClassification::IfcRelAssociatesClassification(std::stri
 
 // Function implementations for IfcRelAssociatesConstraint
 boost::optional< std::string > Ifc4x2::IfcRelAssociatesConstraint::Intent() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x2::IfcConstraint* Ifc4x2::IfcRelAssociatesConstraint::RelatingConstraint() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcConstraint>(true); }
 void Ifc4x2::IfcRelAssociatesConstraint::setRelatingConstraint(::Ifc4x2::IfcConstraint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -18374,7 +18374,7 @@ void Ifc4x2::IfcRelConnectsStructuralMember::setAppliedCondition(::Ifc4x2::IfcBo
 ::Ifc4x2::IfcStructuralConnectionCondition* Ifc4x2::IfcRelConnectsStructuralMember::AdditionalConditions() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x2::IfcStructuralConnectionCondition>(true); }
 void Ifc4x2::IfcRelConnectsStructuralMember::setAdditionalConditions(::Ifc4x2::IfcStructuralConnectionCondition* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcRelConnectsStructuralMember::SupportedLength() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x2::IfcAxis2Placement3D* Ifc4x2::IfcRelConnectsStructuralMember::ConditionCoordinateSystem() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x2::IfcAxis2Placement3D>(true); }
 void Ifc4x2::IfcRelConnectsStructuralMember::setConditionCoordinateSystem(::Ifc4x2::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -18398,7 +18398,7 @@ Ifc4x2::IfcRelConnectsWithEccentricity::IfcRelConnectsWithEccentricity(std::stri
 aggregate_of< ::Ifc4x2::IfcElement >::ptr Ifc4x2::IfcRelConnectsWithRealizingElements::RealizingElements() const {  aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x2::IfcElement >(); }
 void Ifc4x2::IfcRelConnectsWithRealizingElements::setRealizingElements(aggregate_of< ::Ifc4x2::IfcElement >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcRelConnectsWithRealizingElements::ConnectionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcRelConnectsWithRealizingElements::declaration() const { return *IFC4X2_IfcRelConnectsWithRealizingElements_type; }
@@ -18550,7 +18550,7 @@ void Ifc4x2::IfcRelInterferesElements::setRelatedElement(::Ifc4x2::IfcElement* v
 ::Ifc4x2::IfcConnectionGeometry* Ifc4x2::IfcRelInterferesElements::InterferenceGeometry() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcConnectionGeometry>(true); }
 void Ifc4x2::IfcRelInterferesElements::setInterferenceGeometry(::Ifc4x2::IfcConnectionGeometry* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcRelInterferesElements::InterferenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::logic::tribool Ifc4x2::IfcRelInterferesElements::ImpliedOrder() const {  boost::logic::tribool v = *data_->getArgument(8); return v; }
 void Ifc4x2::IfcRelInterferesElements::setImpliedOrder(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -18616,9 +18616,9 @@ void Ifc4x2::IfcRelSequence::setRelatedProcess(::Ifc4x2::IfcProcess* v) { {IfcWr
 ::Ifc4x2::IfcLagTime* Ifc4x2::IfcRelSequence::TimeLag() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcLagTime>(true); }
 void Ifc4x2::IfcRelSequence::setTimeLag(::Ifc4x2::IfcLagTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x2::IfcSequenceEnum::Value > Ifc4x2::IfcRelSequence::SequenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSequenceEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x2::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x2::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSequenceEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x2::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x2::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSequenceEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcRelSequence::UserDefinedSequenceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcRelSequence::declaration() const { return *IFC4X2_IfcRelSequence_type; }
@@ -18712,9 +18712,9 @@ Ifc4x2::IfcReparametrisedCompositeCurveSegment::IfcReparametrisedCompositeCurveS
 ::Ifc4x2::IfcRepresentationContext* Ifc4x2::IfcRepresentation::ContextOfItems() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x2::IfcRepresentationContext>(true); }
 void Ifc4x2::IfcRepresentation::setContextOfItems(::Ifc4x2::IfcRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcRepresentation::RepresentationIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcRepresentation::RepresentationType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc4x2::IfcRepresentationItem >::ptr Ifc4x2::IfcRepresentation::Items() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x2::IfcRepresentationItem >(); }
 void Ifc4x2::IfcRepresentation::setItems(aggregate_of< ::Ifc4x2::IfcRepresentationItem >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 
@@ -18729,9 +18729,9 @@ Ifc4x2::IfcRepresentation::IfcRepresentation(::Ifc4x2::IfcRepresentationContext*
 
 // Function implementations for IfcRepresentationContext
 boost::optional< std::string > Ifc4x2::IfcRepresentationContext::ContextIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcRepresentationContext::ContextType() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x2::IfcRepresentation::list::ptr Ifc4x2::IfcRepresentationContext::RepresentationsInContext() const { return data_->getInverse(IFC4X2_IfcRepresentation_type, 0)->as<IfcRepresentation>(); }
 
@@ -18766,9 +18766,9 @@ Ifc4x2::IfcRepresentationMap::IfcRepresentationMap(::Ifc4x2::IfcAxis2Placement*
 
 // Function implementations for IfcResource
 boost::optional< std::string > Ifc4x2::IfcResource::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResource::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x2::IfcRelAssignsToResource::list::ptr Ifc4x2::IfcResource::ResourceOf() const { return data_->getInverse(IFC4X2_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -18803,9 +18803,9 @@ Ifc4x2::IfcResourceConstraintRelationship::IfcResourceConstraintRelationship(boo
 
 // Function implementations for IfcResourceLevelRelationship
 boost::optional< std::string > Ifc4x2::IfcResourceLevelRelationship::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResourceLevelRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcResourceLevelRelationship::declaration() const { return *IFC4X2_IfcResourceLevelRelationship_type; }
@@ -18815,35 +18815,35 @@ Ifc4x2::IfcResourceLevelRelationship::IfcResourceLevelRelationship(boost::option
 
 // Function implementations for IfcResourceTime
 boost::optional< std::string > Ifc4x2::IfcResourceTime::ScheduleWork() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcResourceTime::ScheduleUsage() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResourceTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResourceTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResourceTime::ScheduleContour() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResourceTime::LevelingDelay() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< bool > Ifc4x2::IfcResourceTime::IsOverAllocated() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResourceTime::StatusTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResourceTime::ActualWork() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x2::IfcResourceTime::ActualUsage() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResourceTime::ActualStart() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x2::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x2::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResourceTime::ActualFinish() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x2::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x2::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x2::IfcResourceTime::RemainingWork() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x2::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x2::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x2::IfcResourceTime::RemainingUsage() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x2::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x2::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x2::IfcResourceTime::Completion() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x2::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x2::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcResourceTime::declaration() const { return *IFC4X2_IfcResourceTime_type; }
@@ -18899,7 +18899,7 @@ Ifc4x2::IfcRightCircularCylinder::IfcRightCircularCylinder(::Ifc4x2::IfcAxis2Pla
 
 // Function implementations for IfcRoof
 boost::optional< ::Ifc4x2::IfcRoofTypeEnum::Value > Ifc4x2::IfcRoof::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcRoofTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x2::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcRoofTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x2::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcRoofTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcRoof::declaration() const { return *IFC4X2_IfcRoof_type; }
@@ -18923,9 +18923,9 @@ void Ifc4x2::IfcRoot::setGlobalId(std::string v) { {IfcWrite::IfcWriteArgument*
 ::Ifc4x2::IfcOwnerHistory* Ifc4x2::IfcRoot::OwnerHistory() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x2::IfcOwnerHistory>(true); }
 void Ifc4x2::IfcRoot::setOwnerHistory(::Ifc4x2::IfcOwnerHistory* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcRoot::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x2::IfcRoot::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcRoot::declaration() const { return *IFC4X2_IfcRoot_type; }
@@ -18945,7 +18945,7 @@ Ifc4x2::IfcRoundedRectangleProfileDef::IfcRoundedRectangleProfileDef(::Ifc4x2::I
 
 // Function implementations for IfcSIUnit
 boost::optional< ::Ifc4x2::IfcSIPrefix::Value > Ifc4x2::IfcSIUnit::Prefix() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSIPrefix::FromString(*data_->getArgument(2)); }
-void Ifc4x2::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x2::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSIPrefix::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x2::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x2::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSIPrefix::ToString(*v)));}data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcSIUnitName::Value Ifc4x2::IfcSIUnit::Name() const {  return ::Ifc4x2::IfcSIUnitName::FromString(*data_->getArgument(3)); }
 void Ifc4x2::IfcSIUnit::setName(::Ifc4x2::IfcSIUnitName::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcSIUnitName::ToString(v)));data_->setArgument(3,attr);} }
 
@@ -18957,7 +18957,7 @@ Ifc4x2::IfcSIUnit::IfcSIUnit(::Ifc4x2::IfcUnitEnum::Value v2_UnitType, boost::op
 
 // Function implementations for IfcSanitaryTerminal
 boost::optional< ::Ifc4x2::IfcSanitaryTerminalTypeEnum::Value > Ifc4x2::IfcSanitaryTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSanitaryTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x2::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSanitaryTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x2::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSanitaryTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSanitaryTerminal::declaration() const { return *IFC4X2_IfcSanitaryTerminal_type; }
@@ -18977,11 +18977,11 @@ Ifc4x2::IfcSanitaryTerminalType::IfcSanitaryTerminalType(std::string v1_GlobalId
 
 // Function implementations for IfcSchedulingTime
 boost::optional< std::string > Ifc4x2::IfcSchedulingTime::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< ::Ifc4x2::IfcDataOriginEnum::Value > Ifc4x2::IfcSchedulingTime::DataOrigin() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } return ::Ifc4x2::IfcDataOriginEnum::FromString(*data_->getArgument(1)); }
-void Ifc4x2::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x2::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDataOriginEnum::ToString(*v)));data_->setArgument(1,attr);} }
+void Ifc4x2::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x2::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcDataOriginEnum::ToString(*v)));}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcSchedulingTime::UserDefinedDataOrigin() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSchedulingTime::declaration() const { return *IFC4X2_IfcSchedulingTime_type; }
@@ -19017,7 +19017,7 @@ void Ifc4x2::IfcSectionReinforcementProperties::setLongitudinalStartPosition(dou
 double Ifc4x2::IfcSectionReinforcementProperties::LongitudinalEndPosition() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcSectionReinforcementProperties::setLongitudinalEndPosition(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcSectionReinforcementProperties::TransversePosition() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcReinforcingBarRoleEnum::Value Ifc4x2::IfcSectionReinforcementProperties::ReinforcementRole() const {  return ::Ifc4x2::IfcReinforcingBarRoleEnum::FromString(*data_->getArgument(3)); }
 void Ifc4x2::IfcSectionReinforcementProperties::setReinforcementRole(::Ifc4x2::IfcReinforcingBarRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcReinforcingBarRoleEnum::ToString(v)));data_->setArgument(3,attr);} }
 ::Ifc4x2::IfcSectionProperties* Ifc4x2::IfcSectionReinforcementProperties::SectionDefinition() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x2::IfcSectionProperties>(true); }
@@ -19071,7 +19071,7 @@ Ifc4x2::IfcSectionedSpine::IfcSectionedSpine(::Ifc4x2::IfcCompositeCurve* v1_Spi
 
 // Function implementations for IfcSensor
 boost::optional< ::Ifc4x2::IfcSensorTypeEnum::Value > Ifc4x2::IfcSensor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSensorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x2::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSensorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x2::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSensorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSensor::declaration() const { return *IFC4X2_IfcSensor_type; }
@@ -19091,7 +19091,7 @@ Ifc4x2::IfcSensorType::IfcSensorType(std::string v1_GlobalId, ::Ifc4x2::IfcOwner
 
 // Function implementations for IfcShadingDevice
 boost::optional< ::Ifc4x2::IfcShadingDeviceTypeEnum::Value > Ifc4x2::IfcShadingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcShadingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcShadingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcShadingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcShadingDevice::declaration() const { return *IFC4X2_IfcShadingDevice_type; }
@@ -19113,9 +19113,9 @@ Ifc4x2::IfcShadingDeviceType::IfcShadingDeviceType(std::string v1_GlobalId, ::If
 aggregate_of< ::Ifc4x2::IfcShapeModel >::ptr Ifc4x2::IfcShapeAspect::ShapeRepresentations() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x2::IfcShapeModel >(); }
 void Ifc4x2::IfcShapeAspect::setShapeRepresentations(aggregate_of< ::Ifc4x2::IfcShapeModel >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcShapeAspect::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcShapeAspect::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::logic::tribool Ifc4x2::IfcShapeAspect::ProductDefinitional() const {  boost::logic::tribool v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcShapeAspect::setProductDefinitional(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x2::IfcProductRepresentationSelect* Ifc4x2::IfcShapeAspect::PartOfProductDefinitionShape() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x2::IfcProductRepresentationSelect>(true); }
@@ -19165,11 +19165,11 @@ Ifc4x2::IfcSimpleProperty::IfcSimpleProperty(std::string v1_Name, boost::optiona
 
 // Function implementations for IfcSimplePropertyTemplate
 boost::optional< ::Ifc4x2::IfcSimplePropertyTemplateTypeEnum::Value > Ifc4x2::IfcSimplePropertyTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSimplePropertyTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x2::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x2::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x2::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x2::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcSimplePropertyTemplate::PrimaryMeasureType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcSimplePropertyTemplate::SecondaryMeasureType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x2::IfcPropertyEnumeration* Ifc4x2::IfcSimplePropertyTemplate::Enumerators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x2::IfcPropertyEnumeration>(true); }
 void Ifc4x2::IfcSimplePropertyTemplate::setEnumerators(::Ifc4x2::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x2::IfcUnit* Ifc4x2::IfcSimplePropertyTemplate::PrimaryUnit() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x2::IfcUnit>(true); }
@@ -19177,9 +19177,9 @@ void Ifc4x2::IfcSimplePropertyTemplate::setPrimaryUnit(::Ifc4x2::IfcUnit* v) { {
 ::Ifc4x2::IfcUnit* Ifc4x2::IfcSimplePropertyTemplate::SecondaryUnit() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x2::IfcUnit>(true); }
 void Ifc4x2::IfcSimplePropertyTemplate::setSecondaryUnit(::Ifc4x2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x2::IfcSimplePropertyTemplate::Expression() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x2::IfcStateEnum::Value > Ifc4x2::IfcSimplePropertyTemplate::AccessState() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x2::IfcStateEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x2::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x2::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcStateEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x2::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x2::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcStateEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSimplePropertyTemplate::declaration() const { return *IFC4X2_IfcSimplePropertyTemplate_type; }
@@ -19189,13 +19189,13 @@ Ifc4x2::IfcSimplePropertyTemplate::IfcSimplePropertyTemplate(std::string v1_Glob
 
 // Function implementations for IfcSite
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x2::IfcSite::RefLatitude() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x2::IfcSite::RefLongitude() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcSite::RefElevation() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x2::IfcSite::LandTitleNumber() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x2::IfcPostalAddress* Ifc4x2::IfcSite::SiteAddress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x2::IfcPostalAddress>(true); }
 void Ifc4x2::IfcSite::setSiteAddress(::Ifc4x2::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -19207,7 +19207,7 @@ Ifc4x2::IfcSite::IfcSite(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory* v2_
 
 // Function implementations for IfcSlab
 boost::optional< ::Ifc4x2::IfcSlabTypeEnum::Value > Ifc4x2::IfcSlab::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSlabTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x2::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSlabTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x2::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSlabTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSlab::declaration() const { return *IFC4X2_IfcSlab_type; }
@@ -19243,11 +19243,11 @@ Ifc4x2::IfcSlabType::IfcSlabType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHist
 
 // Function implementations for IfcSlippageConnectionCondition
 boost::optional< double > Ifc4x2::IfcSlippageConnectionCondition::SlippageX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcSlippageConnectionCondition::SlippageY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcSlippageConnectionCondition::SlippageZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSlippageConnectionCondition::declaration() const { return *IFC4X2_IfcSlippageConnectionCondition_type; }
@@ -19257,7 +19257,7 @@ Ifc4x2::IfcSlippageConnectionCondition::IfcSlippageConnectionCondition(boost::op
 
 // Function implementations for IfcSolarDevice
 boost::optional< ::Ifc4x2::IfcSolarDeviceTypeEnum::Value > Ifc4x2::IfcSolarDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSolarDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSolarDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSolarDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSolarDevice::declaration() const { return *IFC4X2_IfcSolarDevice_type; }
@@ -19285,9 +19285,9 @@ Ifc4x2::IfcSolidModel::IfcSolidModel() : IfcGeometricRepresentationItem((IfcEnti
 
 // Function implementations for IfcSpace
 boost::optional< ::Ifc4x2::IfcSpaceTypeEnum::Value > Ifc4x2::IfcSpace::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x2::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x2::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSpaceTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x2::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x2::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSpaceTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcSpace::ElevationWithFlooring() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 ::Ifc4x2::IfcRelCoversSpaces::list::ptr Ifc4x2::IfcSpace::HasCoverings() const { return data_->getInverse(IFC4X2_IfcRelCoversSpaces_type, 4)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x2::IfcRelSpaceBoundary::list::ptr Ifc4x2::IfcSpace::BoundedBy() const { return data_->getInverse(IFC4X2_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
@@ -19299,7 +19299,7 @@ Ifc4x2::IfcSpace::IfcSpace(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory* v
 
 // Function implementations for IfcSpaceHeater
 boost::optional< ::Ifc4x2::IfcSpaceHeaterTypeEnum::Value > Ifc4x2::IfcSpaceHeater::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSpaceHeaterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x2::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSpaceHeaterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x2::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSpaceHeaterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSpaceHeater::declaration() const { return *IFC4X2_IfcSpaceHeater_type; }
@@ -19321,7 +19321,7 @@ Ifc4x2::IfcSpaceHeaterType::IfcSpaceHeaterType(std::string v1_GlobalId, ::Ifc4x2
 ::Ifc4x2::IfcSpaceTypeEnum::Value Ifc4x2::IfcSpaceType::PredefinedType() const {  return ::Ifc4x2::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x2::IfcSpaceType::setPredefinedType(::Ifc4x2::IfcSpaceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcSpaceTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x2::IfcSpaceType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSpaceType::declaration() const { return *IFC4X2_IfcSpaceType_type; }
@@ -19331,7 +19331,7 @@ Ifc4x2::IfcSpaceType::IfcSpaceType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHi
 
 // Function implementations for IfcSpatialElement
 boost::optional< std::string > Ifc4x2::IfcSpatialElement::LongName() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x2::IfcRelContainedInSpatialStructure::list::ptr Ifc4x2::IfcSpatialElement::ContainsElements() const { return data_->getInverse(IFC4X2_IfcRelContainedInSpatialStructure_type, 5)->as<IfcRelContainedInSpatialStructure>(); }
 ::Ifc4x2::IfcRelServicesBuildings::list::ptr Ifc4x2::IfcSpatialElement::ServicedBySystems() const { return data_->getInverse(IFC4X2_IfcRelServicesBuildings_type, 5)->as<IfcRelServicesBuildings>(); }
@@ -19344,7 +19344,7 @@ Ifc4x2::IfcSpatialElement::IfcSpatialElement(std::string v1_GlobalId, ::Ifc4x2::
 
 // Function implementations for IfcSpatialElementType
 boost::optional< std::string > Ifc4x2::IfcSpatialElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSpatialElementType::declaration() const { return *IFC4X2_IfcSpatialElementType_type; }
@@ -19354,7 +19354,7 @@ Ifc4x2::IfcSpatialElementType::IfcSpatialElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcSpatialStructureElement
 boost::optional< ::Ifc4x2::IfcElementCompositionEnum::Value > Ifc4x2::IfcSpatialStructureElement::CompositionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcElementCompositionEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x2::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElementCompositionEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x2::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcElementCompositionEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSpatialStructureElement::declaration() const { return *IFC4X2_IfcSpatialStructureElement_type; }
@@ -19372,7 +19372,7 @@ Ifc4x2::IfcSpatialStructureElementType::IfcSpatialStructureElementType(std::stri
 
 // Function implementations for IfcSpatialZone
 boost::optional< ::Ifc4x2::IfcSpatialZoneTypeEnum::Value > Ifc4x2::IfcSpatialZone::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x2::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSpatialZoneTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x2::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSpatialZoneTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSpatialZone::declaration() const { return *IFC4X2_IfcSpatialZone_type; }
@@ -19384,7 +19384,7 @@ Ifc4x2::IfcSpatialZone::IfcSpatialZone(std::string v1_GlobalId, ::Ifc4x2::IfcOwn
 ::Ifc4x2::IfcSpatialZoneTypeEnum::Value Ifc4x2::IfcSpatialZoneType::PredefinedType() const {  return ::Ifc4x2::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x2::IfcSpatialZoneType::setPredefinedType(::Ifc4x2::IfcSpatialZoneTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcSpatialZoneTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x2::IfcSpatialZoneType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSpatialZoneType::declaration() const { return *IFC4X2_IfcSpatialZoneType_type; }
@@ -19414,7 +19414,7 @@ Ifc4x2::IfcSphericalSurface::IfcSphericalSurface(::Ifc4x2::IfcAxis2Placement3D*
 
 // Function implementations for IfcStackTerminal
 boost::optional< ::Ifc4x2::IfcStackTerminalTypeEnum::Value > Ifc4x2::IfcStackTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcStackTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x2::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcStackTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x2::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcStackTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStackTerminal::declaration() const { return *IFC4X2_IfcStackTerminal_type; }
@@ -19434,7 +19434,7 @@ Ifc4x2::IfcStackTerminalType::IfcStackTerminalType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcStair
 boost::optional< ::Ifc4x2::IfcStairTypeEnum::Value > Ifc4x2::IfcStair::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcStairTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcStair::setPredefinedType(boost::optional< ::Ifc4x2::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcStairTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcStair::setPredefinedType(boost::optional< ::Ifc4x2::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcStairTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStair::declaration() const { return *IFC4X2_IfcStair_type; }
@@ -19444,15 +19444,15 @@ Ifc4x2::IfcStair::IfcStair(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory* v
 
 // Function implementations for IfcStairFlight
 boost::optional< int > Ifc4x2::IfcStairFlight::NumberOfRisers() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } int v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< int > Ifc4x2::IfcStairFlight::NumberOfTreads() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } int v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcStairFlight::RiserHeight() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcStairFlight::TreadLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x2::IfcStairFlightTypeEnum::Value > Ifc4x2::IfcStairFlight::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x2::IfcStairFlightTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x2::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x2::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcStairFlightTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x2::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x2::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcStairFlightTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStairFlight::declaration() const { return *IFC4X2_IfcStairFlight_type; }
@@ -19482,7 +19482,7 @@ Ifc4x2::IfcStairType::IfcStairType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHi
 
 // Function implementations for IfcStructuralAction
 boost::optional< bool > Ifc4x2::IfcStructuralAction::DestabilizingLoad() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralAction::declaration() const { return *IFC4X2_IfcStructuralAction_type; }
@@ -19509,9 +19509,9 @@ void Ifc4x2::IfcStructuralAnalysisModel::setPredefinedType(::Ifc4x2::IfcAnalysis
 ::Ifc4x2::IfcAxis2Placement3D* Ifc4x2::IfcStructuralAnalysisModel::OrientationOf2DPlane() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcAxis2Placement3D>(true); }
 void Ifc4x2::IfcStructuralAnalysisModel::setOrientationOf2DPlane(::Ifc4x2::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcStructuralLoadGroup >::ptr > Ifc4x2::IfcStructuralAnalysisModel::LoadedBy() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x2::IfcStructuralLoadGroup >(); }
-void Ifc4x2::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x2::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x2::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x2::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcStructuralResultGroup >::ptr > Ifc4x2::IfcStructuralAnalysisModel::HasResults() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x2::IfcStructuralResultGroup >(); }
-void Ifc4x2::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x2::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x2::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x2::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x2::IfcObjectPlacement* Ifc4x2::IfcStructuralAnalysisModel::SharedPlacement() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x2::IfcObjectPlacement>(true); }
 void Ifc4x2::IfcStructuralAnalysisModel::setSharedPlacement(::Ifc4x2::IfcObjectPlacement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -19534,7 +19534,7 @@ Ifc4x2::IfcStructuralConnection::IfcStructuralConnection(std::string v1_GlobalId
 
 // Function implementations for IfcStructuralConnectionCondition
 boost::optional< std::string > Ifc4x2::IfcStructuralConnectionCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralConnectionCondition::declaration() const { return *IFC4X2_IfcStructuralConnectionCondition_type; }
@@ -19544,7 +19544,7 @@ Ifc4x2::IfcStructuralConnectionCondition::IfcStructuralConnectionCondition(boost
 
 // Function implementations for IfcStructuralCurveAction
 boost::optional< ::Ifc4x2::IfcProjectedOrTrueLengthEnum::Value > Ifc4x2::IfcStructuralCurveAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x2::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x2::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x2::IfcStructuralCurveActivityTypeEnum::Value Ifc4x2::IfcStructuralCurveAction::PredefinedType() const {  return ::Ifc4x2::IfcStructuralCurveActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x2::IfcStructuralCurveAction::setPredefinedType(::Ifc4x2::IfcStructuralCurveActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcStructuralCurveActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -19613,7 +19613,7 @@ Ifc4x2::IfcStructuralLinearAction::IfcStructuralLinearAction(std::string v1_Glob
 
 // Function implementations for IfcStructuralLoad
 boost::optional< std::string > Ifc4x2::IfcStructuralLoad::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralLoad::declaration() const { return *IFC4X2_IfcStructuralLoad_type; }
@@ -19623,7 +19623,7 @@ Ifc4x2::IfcStructuralLoad::IfcStructuralLoad(boost::optional< std::string > v1_N
 
 // Function implementations for IfcStructuralLoadCase
 boost::optional< std::vector< double > /*[3:3]*/ > Ifc4x2::IfcStructuralLoadCase::SelfWeightCoefficients() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< double > /*[3:3]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralLoadCase::declaration() const { return *IFC4X2_IfcStructuralLoadCase_type; }
@@ -19635,7 +19635,7 @@ Ifc4x2::IfcStructuralLoadCase::IfcStructuralLoadCase(std::string v1_GlobalId, ::
 aggregate_of< ::Ifc4x2::IfcStructuralLoadOrResult >::ptr Ifc4x2::IfcStructuralLoadConfiguration::Values() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x2::IfcStructuralLoadOrResult >(); }
 void Ifc4x2::IfcStructuralLoadConfiguration::setValues(aggregate_of< ::Ifc4x2::IfcStructuralLoadOrResult >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::vector< std::vector< double > > > Ifc4x2::IfcStructuralLoadConfiguration::Locations() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralLoadConfiguration::declaration() const { return *IFC4X2_IfcStructuralLoadConfiguration_type; }
@@ -19651,9 +19651,9 @@ void Ifc4x2::IfcStructuralLoadGroup::setActionType(::Ifc4x2::IfcActionTypeEnum::
 ::Ifc4x2::IfcActionSourceTypeEnum::Value Ifc4x2::IfcStructuralLoadGroup::ActionSource() const {  return ::Ifc4x2::IfcActionSourceTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x2::IfcStructuralLoadGroup::setActionSource(::Ifc4x2::IfcActionSourceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcActionSourceTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadGroup::Coefficient() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x2::IfcStructuralLoadGroup::Purpose() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 ::Ifc4x2::IfcStructuralResultGroup::list::ptr Ifc4x2::IfcStructuralLoadGroup::SourceOfResultGroup() const { return data_->getInverse(IFC4X2_IfcStructuralResultGroup_type, 6)->as<IfcStructuralResultGroup>(); }
 ::Ifc4x2::IfcStructuralAnalysisModel::list::ptr Ifc4x2::IfcStructuralLoadGroup::LoadGroupFor() const { return data_->getInverse(IFC4X2_IfcStructuralAnalysisModel_type, 7)->as<IfcStructuralAnalysisModel>(); }
@@ -19665,17 +19665,17 @@ Ifc4x2::IfcStructuralLoadGroup::IfcStructuralLoadGroup(std::string v1_GlobalId,
 
 // Function implementations for IfcStructuralLoadLinearForce
 boost::optional< double > Ifc4x2::IfcStructuralLoadLinearForce::LinearForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadLinearForce::LinearForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadLinearForce::LinearForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadLinearForce::LinearMomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadLinearForce::LinearMomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadLinearForce::LinearMomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralLoadLinearForce::declaration() const { return *IFC4X2_IfcStructuralLoadLinearForce_type; }
@@ -19693,11 +19693,11 @@ Ifc4x2::IfcStructuralLoadOrResult::IfcStructuralLoadOrResult(boost::optional< st
 
 // Function implementations for IfcStructuralLoadPlanarForce
 boost::optional< double > Ifc4x2::IfcStructuralLoadPlanarForce::PlanarForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadPlanarForce::PlanarForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadPlanarForce::PlanarForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralLoadPlanarForce::declaration() const { return *IFC4X2_IfcStructuralLoadPlanarForce_type; }
@@ -19707,17 +19707,17 @@ Ifc4x2::IfcStructuralLoadPlanarForce::IfcStructuralLoadPlanarForce(boost::option
 
 // Function implementations for IfcStructuralLoadSingleDisplacement
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleDisplacement::DisplacementX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleDisplacement::DisplacementY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleDisplacement::DisplacementZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralLoadSingleDisplacement::declaration() const { return *IFC4X2_IfcStructuralLoadSingleDisplacement_type; }
@@ -19727,7 +19727,7 @@ Ifc4x2::IfcStructuralLoadSingleDisplacement::IfcStructuralLoadSingleDisplacement
 
 // Function implementations for IfcStructuralLoadSingleDisplacementDistortion
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleDisplacementDistortion::Distortion() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralLoadSingleDisplacementDistortion::declaration() const { return *IFC4X2_IfcStructuralLoadSingleDisplacementDistortion_type; }
@@ -19737,17 +19737,17 @@ Ifc4x2::IfcStructuralLoadSingleDisplacementDistortion::IfcStructuralLoadSingleDi
 
 // Function implementations for IfcStructuralLoadSingleForce
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleForce::ForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleForce::ForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleForce::ForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleForce::MomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleForce::MomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleForce::MomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralLoadSingleForce::declaration() const { return *IFC4X2_IfcStructuralLoadSingleForce_type; }
@@ -19757,7 +19757,7 @@ Ifc4x2::IfcStructuralLoadSingleForce::IfcStructuralLoadSingleForce(boost::option
 
 // Function implementations for IfcStructuralLoadSingleForceWarping
 boost::optional< double > Ifc4x2::IfcStructuralLoadSingleForceWarping::WarpingMoment() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralLoadSingleForceWarping::declaration() const { return *IFC4X2_IfcStructuralLoadSingleForceWarping_type; }
@@ -19775,11 +19775,11 @@ Ifc4x2::IfcStructuralLoadStatic::IfcStructuralLoadStatic(boost::optional< std::s
 
 // Function implementations for IfcStructuralLoadTemperature
 boost::optional< double > Ifc4x2::IfcStructuralLoadTemperature::DeltaTConstant() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadTemperature::DeltaTY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralLoadTemperature::DeltaTZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralLoadTemperature::declaration() const { return *IFC4X2_IfcStructuralLoadTemperature_type; }
@@ -19855,7 +19855,7 @@ Ifc4x2::IfcStructuralResultGroup::IfcStructuralResultGroup(std::string v1_Global
 
 // Function implementations for IfcStructuralSurfaceAction
 boost::optional< ::Ifc4x2::IfcProjectedOrTrueLengthEnum::Value > Ifc4x2::IfcStructuralSurfaceAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x2::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x2::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x2::IfcStructuralSurfaceActivityTypeEnum::Value Ifc4x2::IfcStructuralSurfaceAction::PredefinedType() const {  return ::Ifc4x2::IfcStructuralSurfaceActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x2::IfcStructuralSurfaceAction::setPredefinedType(::Ifc4x2::IfcStructuralSurfaceActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcStructuralSurfaceActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -19877,7 +19877,7 @@ Ifc4x2::IfcStructuralSurfaceConnection::IfcStructuralSurfaceConnection(std::stri
 ::Ifc4x2::IfcStructuralSurfaceMemberTypeEnum::Value Ifc4x2::IfcStructuralSurfaceMember::PredefinedType() const {  return ::Ifc4x2::IfcStructuralSurfaceMemberTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x2::IfcStructuralSurfaceMember::setPredefinedType(::Ifc4x2::IfcStructuralSurfaceMemberTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcStructuralSurfaceMemberTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcStructuralSurfaceMember::Thickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStructuralSurfaceMember::declaration() const { return *IFC4X2_IfcStructuralSurfaceMember_type; }
@@ -19917,7 +19917,7 @@ void Ifc4x2::IfcStyledItem::setItem(::Ifc4x2::IfcRepresentationItem* v) { {IfcWr
 aggregate_of_instance::ptr Ifc4x2::IfcStyledItem::Styles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcStyledItem::setStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcStyledItem::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcStyledItem::declaration() const { return *IFC4X2_IfcStyledItem_type; }
@@ -19935,7 +19935,7 @@ Ifc4x2::IfcStyledRepresentation::IfcStyledRepresentation(::Ifc4x2::IfcRepresenta
 
 // Function implementations for IfcSubContractResource
 boost::optional< ::Ifc4x2::IfcSubContractResourceTypeEnum::Value > Ifc4x2::IfcSubContractResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSubContractResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSubContractResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x2::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSubContractResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSubContractResource::declaration() const { return *IFC4X2_IfcSubContractResource_type; }
@@ -19989,9 +19989,9 @@ Ifc4x2::IfcSurfaceCurve::IfcSurfaceCurve(::Ifc4x2::IfcCurve* v1_Curve3D, aggrega
 ::Ifc4x2::IfcCurve* Ifc4x2::IfcSurfaceCurveSweptAreaSolid::Directrix() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x2::IfcCurve>(true); }
 void Ifc4x2::IfcSurfaceCurveSweptAreaSolid::setDirectrix(::Ifc4x2::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcSurfaceCurveSweptAreaSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcSurfaceCurveSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcSurfaceCurveSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcSurfaceCurveSweptAreaSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcSurfaceCurveSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcSurfaceCurveSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x2::IfcSurface* Ifc4x2::IfcSurfaceCurveSweptAreaSolid::ReferenceSurface() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x2::IfcSurface>(true); }
 void Ifc4x2::IfcSurfaceCurveSweptAreaSolid::setReferenceSurface(::Ifc4x2::IfcSurface* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -20003,7 +20003,7 @@ Ifc4x2::IfcSurfaceCurveSweptAreaSolid::IfcSurfaceCurveSweptAreaSolid(::Ifc4x2::I
 
 // Function implementations for IfcSurfaceFeature
 boost::optional< ::Ifc4x2::IfcSurfaceFeatureTypeEnum::Value > Ifc4x2::IfcSurfaceFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSurfaceFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x2::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSurfaceFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x2::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSurfaceFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSurfaceFeature::declaration() const { return *IFC4X2_IfcSurfaceFeature_type; }
@@ -20035,11 +20035,11 @@ Ifc4x2::IfcSurfaceOfRevolution::IfcSurfaceOfRevolution(::Ifc4x2::IfcProfileDef*
 
 // Function implementations for IfcSurfaceReinforcementArea
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x2::IfcSurfaceReinforcementArea::SurfaceReinforcement1() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x2::IfcSurfaceReinforcementArea::SurfaceReinforcement2() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcSurfaceReinforcementArea::ShearReinforcement() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSurfaceReinforcementArea::declaration() const { return *IFC4X2_IfcSurfaceReinforcementArea_type; }
@@ -20077,9 +20077,9 @@ Ifc4x2::IfcSurfaceStyleLighting::IfcSurfaceStyleLighting(::Ifc4x2::IfcColourRgb*
 
 // Function implementations for IfcSurfaceStyleRefraction
 boost::optional< double > Ifc4x2::IfcSurfaceStyleRefraction::RefractionIndex() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x2::IfcSurfaceStyleRefraction::DispersionFactor() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSurfaceStyleRefraction::declaration() const { return *IFC4X2_IfcSurfaceStyleRefraction_type; }
@@ -20113,7 +20113,7 @@ Ifc4x2::IfcSurfaceStyleRendering::IfcSurfaceStyleRendering(::Ifc4x2::IfcColourRg
 ::Ifc4x2::IfcColourRgb* Ifc4x2::IfcSurfaceStyleShading::SurfaceColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x2::IfcColourRgb>(true); }
 void Ifc4x2::IfcSurfaceStyleShading::setSurfaceColour(::Ifc4x2::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x2::IfcSurfaceStyleShading::Transparency() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSurfaceStyleShading::declaration() const { return *IFC4X2_IfcSurfaceStyleShading_type; }
@@ -20137,11 +20137,11 @@ void Ifc4x2::IfcSurfaceTexture::setRepeatS(bool v) { {IfcWrite::IfcWriteArgument
 bool Ifc4x2::IfcSurfaceTexture::RepeatT() const {  bool v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcSurfaceTexture::setRepeatT(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcSurfaceTexture::Mode() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcCartesianTransformationOperator2D* Ifc4x2::IfcSurfaceTexture::TextureTransform() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x2::IfcSurfaceTexture::setTextureTransform(::Ifc4x2::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcSurfaceTexture::Parameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x2::IfcTextureCoordinate::list::ptr Ifc4x2::IfcSurfaceTexture::IsMappedBy() const { return data_->getInverse(IFC4X2_IfcTextureCoordinate_type, 0)->as<IfcTextureCoordinate>(); }
 ::Ifc4x2::IfcSurfaceStyleWithTextures::list::ptr Ifc4x2::IfcSurfaceTexture::UsedInStyles() const { return data_->getInverse(IFC4X2_IfcSurfaceStyleWithTextures_type, 0)->as<IfcSurfaceStyleWithTextures>(); }
@@ -20169,11 +20169,11 @@ void Ifc4x2::IfcSweptDiskSolid::setDirectrix(::Ifc4x2::IfcCurve* v) { {IfcWrite:
 double Ifc4x2::IfcSweptDiskSolid::Radius() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcSweptDiskSolid::setRadius(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x2::IfcSweptDiskSolid::InnerRadius() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x2::IfcSweptDiskSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcSweptDiskSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSweptDiskSolid::declaration() const { return *IFC4X2_IfcSweptDiskSolid_type; }
@@ -20183,7 +20183,7 @@ Ifc4x2::IfcSweptDiskSolid::IfcSweptDiskSolid(::Ifc4x2::IfcCurve* v1_Directrix, d
 
 // Function implementations for IfcSweptDiskSolidPolygonal
 boost::optional< double > Ifc4x2::IfcSweptDiskSolidPolygonal::FilletRadius() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSweptDiskSolidPolygonal::declaration() const { return *IFC4X2_IfcSweptDiskSolidPolygonal_type; }
@@ -20205,7 +20205,7 @@ Ifc4x2::IfcSweptSurface::IfcSweptSurface(::Ifc4x2::IfcProfileDef* v1_SweptCurve,
 
 // Function implementations for IfcSwitchingDevice
 boost::optional< ::Ifc4x2::IfcSwitchingDeviceTypeEnum::Value > Ifc4x2::IfcSwitchingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSwitchingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSwitchingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x2::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSwitchingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSwitchingDevice::declaration() const { return *IFC4X2_IfcSwitchingDevice_type; }
@@ -20234,7 +20234,7 @@ Ifc4x2::IfcSystem::IfcSystem(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory*
 
 // Function implementations for IfcSystemFurnitureElement
 boost::optional< ::Ifc4x2::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x2::IfcSystemFurnitureElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSystemFurnitureElement::declaration() const { return *IFC4X2_IfcSystemFurnitureElement_type; }
@@ -20244,7 +20244,7 @@ Ifc4x2::IfcSystemFurnitureElement::IfcSystemFurnitureElement(std::string v1_Glob
 
 // Function implementations for IfcSystemFurnitureElementType
 boost::optional< ::Ifc4x2::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x2::IfcSystemFurnitureElementType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x2::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x2::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x2::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x2::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x2::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcSystemFurnitureElementType::declaration() const { return *IFC4X2_IfcSystemFurnitureElementType_type; }
@@ -20262,15 +20262,15 @@ void Ifc4x2::IfcTShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc4x2::IfcTShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x2::IfcTShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcTShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcTShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x2::IfcTShapeProfileDef::WebEdgeRadius() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcTShapeProfileDef::WebSlope() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcTShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTShapeProfileDef::declaration() const { return *IFC4X2_IfcTShapeProfileDef_type; }
@@ -20280,11 +20280,11 @@ Ifc4x2::IfcTShapeProfileDef::IfcTShapeProfileDef(::Ifc4x2::IfcProfileTypeEnum::V
 
 // Function implementations for IfcTable
 boost::optional< std::string > Ifc4x2::IfcTable::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcTableRow >::ptr > Ifc4x2::IfcTable::Rows() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x2::IfcTableRow >(); }
-void Ifc4x2::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x2::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x2::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x2::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcTableColumn >::ptr > Ifc4x2::IfcTable::Columns() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x2::IfcTableColumn >(); }
-void Ifc4x2::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x2::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x2::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x2::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTable::declaration() const { return *IFC4X2_IfcTable_type; }
@@ -20294,11 +20294,11 @@ Ifc4x2::IfcTable::IfcTable(boost::optional< std::string > v1_Name, boost::option
 
 // Function implementations for IfcTableColumn
 boost::optional< std::string > Ifc4x2::IfcTableColumn::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTableColumn::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTableColumn::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcUnit* Ifc4x2::IfcTableColumn::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcUnit>(true); }
 void Ifc4x2::IfcTableColumn::setUnit(::Ifc4x2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x2::IfcReference* Ifc4x2::IfcTableColumn::ReferencePath() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x2::IfcReference>(true); }
@@ -20312,9 +20312,9 @@ Ifc4x2::IfcTableColumn::IfcTableColumn(boost::optional< std::string > v1_Identif
 
 // Function implementations for IfcTableRow
 boost::optional< aggregate_of_instance::ptr > Ifc4x2::IfcTableRow::RowCells() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(0); return v; }
-void Ifc4x2::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x2::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< bool > Ifc4x2::IfcTableRow::IsHeading() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTableRow::declaration() const { return *IFC4X2_IfcTableRow_type; }
@@ -20324,7 +20324,7 @@ Ifc4x2::IfcTableRow::IfcTableRow(boost::optional< aggregate_of_instance::ptr > v
 
 // Function implementations for IfcTank
 boost::optional< ::Ifc4x2::IfcTankTypeEnum::Value > Ifc4x2::IfcTank::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcTankTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcTank::setPredefinedType(boost::optional< ::Ifc4x2::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTankTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcTank::setPredefinedType(boost::optional< ::Ifc4x2::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTankTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTank::declaration() const { return *IFC4X2_IfcTank_type; }
@@ -20344,17 +20344,17 @@ Ifc4x2::IfcTankType::IfcTankType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHist
 
 // Function implementations for IfcTask
 boost::optional< std::string > Ifc4x2::IfcTask::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTask::WorkMethod() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 bool Ifc4x2::IfcTask::IsMilestone() const {  bool v = *data_->getArgument(9); return v; }
 void Ifc4x2::IfcTask::setIsMilestone(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< int > Ifc4x2::IfcTask::Priority() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } int v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x2::IfcTaskTime* Ifc4x2::IfcTask::TaskTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x2::IfcTaskTime>(true); }
 void Ifc4x2::IfcTask::setTaskTime(::Ifc4x2::IfcTaskTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x2::IfcTaskTypeEnum::Value > Ifc4x2::IfcTask::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x2::IfcTaskTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x2::IfcTask::setPredefinedType(boost::optional< ::Ifc4x2::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTaskTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x2::IfcTask::setPredefinedType(boost::optional< ::Ifc4x2::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTaskTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTask::declaration() const { return *IFC4X2_IfcTask_type; }
@@ -20364,39 +20364,39 @@ Ifc4x2::IfcTask::IfcTask(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory* v2_
 
 // Function implementations for IfcTaskTime
 boost::optional< ::Ifc4x2::IfcTaskDurationEnum::Value > Ifc4x2::IfcTaskTime::DurationType() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x2::IfcTaskDurationEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x2::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x2::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTaskDurationEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x2::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x2::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTaskDurationEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::ScheduleDuration() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::EarlyStart() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::EarlyFinish() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::LateStart() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::LateFinish() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::FreeFloat() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::TotalFloat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< bool > Ifc4x2::IfcTaskTime::IsCritical() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } bool v = *data_->getArgument(13); return v; }
-void Ifc4x2::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x2::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::StatusTime() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x2::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x2::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::ActualDuration() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x2::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x2::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::ActualStart() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } std::string v = *data_->getArgument(16); return v; }
-void Ifc4x2::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x2::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::ActualFinish() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } std::string v = *data_->getArgument(17); return v; }
-void Ifc4x2::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x2::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskTime::RemainingTime() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x2::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x2::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< double > Ifc4x2::IfcTaskTime::Completion() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } double v = *data_->getArgument(19); return v; }
-void Ifc4x2::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x2::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTaskTime::declaration() const { return *IFC4X2_IfcTaskTime_type; }
@@ -20418,7 +20418,7 @@ Ifc4x2::IfcTaskTimeRecurring::IfcTaskTimeRecurring(boost::optional< std::string
 ::Ifc4x2::IfcTaskTypeEnum::Value Ifc4x2::IfcTaskType::PredefinedType() const {  return ::Ifc4x2::IfcTaskTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x2::IfcTaskType::setPredefinedType(::Ifc4x2::IfcTaskTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcTaskTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTaskType::WorkMethod() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTaskType::declaration() const { return *IFC4X2_IfcTaskType_type; }
@@ -20428,17 +20428,17 @@ Ifc4x2::IfcTaskType::IfcTaskType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHist
 
 // Function implementations for IfcTelecomAddress
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcTelecomAddress::TelephoneNumbers() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcTelecomAddress::FacsimileNumbers() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTelecomAddress::PagerNumber() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcTelecomAddress::ElectronicMailAddresses() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTelecomAddress::WWWHomePageURL() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x2::IfcTelecomAddress::MessagingIDs() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTelecomAddress::declaration() const { return *IFC4X2_IfcTelecomAddress_type; }
@@ -20448,21 +20448,21 @@ Ifc4x2::IfcTelecomAddress::IfcTelecomAddress(boost::optional< ::Ifc4x2::IfcAddre
 
 // Function implementations for IfcTendon
 boost::optional< ::Ifc4x2::IfcTendonTypeEnum::Value > Ifc4x2::IfcTendon::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x2::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x2::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x2::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTendonTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x2::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x2::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTendonTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcTendon::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcTendon::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x2::IfcTendon::TensionForce() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x2::IfcTendon::PreStress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x2::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x2::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x2::IfcTendon::FrictionCoefficient() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x2::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x2::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x2::IfcTendon::AnchorageSlip() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x2::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x2::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x2::IfcTendon::MinCurvatureRadius() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x2::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x2::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTendon::declaration() const { return *IFC4X2_IfcTendon_type; }
@@ -20472,7 +20472,7 @@ Ifc4x2::IfcTendon::IfcTendon(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory*
 
 // Function implementations for IfcTendonAnchor
 boost::optional< ::Ifc4x2::IfcTendonAnchorTypeEnum::Value > Ifc4x2::IfcTendonAnchor::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x2::IfcTendonAnchorTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x2::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x2::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTendonAnchorTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x2::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x2::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTendonAnchorTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTendonAnchor::declaration() const { return *IFC4X2_IfcTendonAnchor_type; }
@@ -20514,11 +20514,11 @@ Ifc4x2::IfcTendonConduitType::IfcTendonConduitType(std::string v1_GlobalId, ::If
 ::Ifc4x2::IfcTendonTypeEnum::Value Ifc4x2::IfcTendonType::PredefinedType() const {  return ::Ifc4x2::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x2::IfcTendonType::setPredefinedType(::Ifc4x2::IfcTendonTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcTendonTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcTendonType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcTendonType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x2::IfcTendonType::SheathDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTendonType::declaration() const { return *IFC4X2_IfcTendonType_type; }
@@ -20580,7 +20580,7 @@ void Ifc4x2::IfcTextStyle::setTextStyle(::Ifc4x2::IfcTextStyleTextModel* v) { {I
 ::Ifc4x2::IfcTextFontSelect* Ifc4x2::IfcTextStyle::TextFontStyle() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcTextFontSelect>(true); }
 void Ifc4x2::IfcTextStyle::setTextFontStyle(::Ifc4x2::IfcTextFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x2::IfcTextStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTextStyle::declaration() const { return *IFC4X2_IfcTextStyle_type; }
@@ -20592,11 +20592,11 @@ Ifc4x2::IfcTextStyle::IfcTextStyle(boost::optional< std::string > v1_Name, ::Ifc
 std::vector< std::string > /*[1:?]*/ Ifc4x2::IfcTextStyleFontModel::FontFamily() const {  std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcTextStyleFontModel::setFontFamily(std::vector< std::string > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTextStyleFontModel::FontStyle() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTextStyleFontModel::FontVariant() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTextStyleFontModel::FontWeight() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x2::IfcSizeSelect* Ifc4x2::IfcTextStyleFontModel::FontSize() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x2::IfcSizeSelect>(true); }
 void Ifc4x2::IfcTextStyleFontModel::setFontSize(::Ifc4x2::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -20622,15 +20622,15 @@ Ifc4x2::IfcTextStyleForDefinedFont::IfcTextStyleForDefinedFont(::Ifc4x2::IfcColo
 ::Ifc4x2::IfcSizeSelect* Ifc4x2::IfcTextStyleTextModel::TextIndent() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x2::IfcSizeSelect>(true); }
 void Ifc4x2::IfcTextStyleTextModel::setTextIndent(::Ifc4x2::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTextStyleTextModel::TextAlign() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTextStyleTextModel::TextDecoration() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x2::IfcSizeSelect* Ifc4x2::IfcTextStyleTextModel::LetterSpacing() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcSizeSelect>(true); }
 void Ifc4x2::IfcTextStyleTextModel::setLetterSpacing(::Ifc4x2::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x2::IfcSizeSelect* Ifc4x2::IfcTextStyleTextModel::WordSpacing() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x2::IfcSizeSelect>(true); }
 void Ifc4x2::IfcTextStyleTextModel::setWordSpacing(::Ifc4x2::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTextStyleTextModel::TextTransform() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x2::IfcSizeSelect* Ifc4x2::IfcTextStyleTextModel::LineHeight() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x2::IfcSizeSelect>(true); }
 void Ifc4x2::IfcTextStyleTextModel::setLineHeight(::Ifc4x2::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -20654,7 +20654,7 @@ Ifc4x2::IfcTextureCoordinate::IfcTextureCoordinate(aggregate_of< ::Ifc4x2::IfcSu
 std::string Ifc4x2::IfcTextureCoordinateGenerator::Mode() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x2::IfcTextureCoordinateGenerator::setMode(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[1:?]*/ > Ifc4x2::IfcTextureCoordinateGenerator::Parameter() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTextureCoordinateGenerator::declaration() const { return *IFC4X2_IfcTextureCoordinateGenerator_type; }
@@ -20710,7 +20710,7 @@ Ifc4x2::IfcTimePeriod::IfcTimePeriod(std::string v1_StartTime, std::string v2_En
 std::string Ifc4x2::IfcTimeSeries::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x2::IfcTimeSeries::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTimeSeries::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 std::string Ifc4x2::IfcTimeSeries::StartTime() const {  std::string v = *data_->getArgument(2); return v; }
 void Ifc4x2::IfcTimeSeries::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::string Ifc4x2::IfcTimeSeries::EndTime() const {  std::string v = *data_->getArgument(3); return v; }
@@ -20720,7 +20720,7 @@ void Ifc4x2::IfcTimeSeries::setTimeSeriesDataType(::Ifc4x2::IfcTimeSeriesDataTyp
 ::Ifc4x2::IfcDataOriginEnum::Value Ifc4x2::IfcTimeSeries::DataOrigin() const {  return ::Ifc4x2::IfcDataOriginEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x2::IfcTimeSeries::setDataOrigin(::Ifc4x2::IfcDataOriginEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcDataOriginEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTimeSeries::UserDefinedDataOrigin() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x2::IfcUnit* Ifc4x2::IfcTimeSeries::Unit() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x2::IfcUnit>(true); }
 void Ifc4x2::IfcTimeSeries::setUnit(::Ifc4x2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 
@@ -20771,7 +20771,7 @@ Ifc4x2::IfcToroidalSurface::IfcToroidalSurface(::Ifc4x2::IfcAxis2Placement3D* v1
 
 // Function implementations for IfcTransformer
 boost::optional< ::Ifc4x2::IfcTransformerTypeEnum::Value > Ifc4x2::IfcTransformer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcTransformerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x2::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTransformerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x2::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTransformerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTransformer::declaration() const { return *IFC4X2_IfcTransformer_type; }
@@ -20791,9 +20791,9 @@ Ifc4x2::IfcTransformerType::IfcTransformerType(std::string v1_GlobalId, ::Ifc4x2
 
 // Function implementations for IfcTransitionCurveSegment2D
 boost::optional< double > Ifc4x2::IfcTransitionCurveSegment2D::StartRadius() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x2::IfcTransitionCurveSegment2D::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x2::IfcTransitionCurveSegment2D::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x2::IfcTransitionCurveSegment2D::EndRadius() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcTransitionCurveSegment2D::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcTransitionCurveSegment2D::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 bool Ifc4x2::IfcTransitionCurveSegment2D::IsStartRadiusCCW() const {  bool v = *data_->getArgument(5); return v; }
 void Ifc4x2::IfcTransitionCurveSegment2D::setIsStartRadiusCCW(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 bool Ifc4x2::IfcTransitionCurveSegment2D::IsEndRadiusCCW() const {  bool v = *data_->getArgument(6); return v; }
@@ -20809,7 +20809,7 @@ Ifc4x2::IfcTransitionCurveSegment2D::IfcTransitionCurveSegment2D(::Ifc4x2::IfcCa
 
 // Function implementations for IfcTransportElement
 boost::optional< ::Ifc4x2::IfcTransportElementTypeEnum::Value > Ifc4x2::IfcTransportElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcTransportElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcTransportElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcTransportElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTransportElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcTransportElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcTransportElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTransportElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTransportElement::declaration() const { return *IFC4X2_IfcTransportElement_type; }
@@ -20845,13 +20845,13 @@ Ifc4x2::IfcTrapeziumProfileDef::IfcTrapeziumProfileDef(::Ifc4x2::IfcProfileTypeE
 
 // Function implementations for IfcTriangulatedFaceSet
 boost::optional< std::vector< std::vector< double > > > Ifc4x2::IfcTriangulatedFaceSet::Normals() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(1); return v; }
-void Ifc4x2::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x2::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x2::IfcTriangulatedFaceSet::Closed() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x2::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x2::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::vector< std::vector< int > > Ifc4x2::IfcTriangulatedFaceSet::CoordIndex() const {  std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
 void Ifc4x2::IfcTriangulatedFaceSet::setCoordIndex(std::vector< std::vector< int > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x2::IfcTriangulatedFaceSet::PnIndex() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTriangulatedFaceSet::declaration() const { return *IFC4X2_IfcTriangulatedFaceSet_type; }
@@ -20889,7 +20889,7 @@ Ifc4x2::IfcTrimmedCurve::IfcTrimmedCurve(::Ifc4x2::IfcCurve* v1_BasisCurve, aggr
 
 // Function implementations for IfcTubeBundle
 boost::optional< ::Ifc4x2::IfcTubeBundleTypeEnum::Value > Ifc4x2::IfcTubeBundle::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcTubeBundleTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x2::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTubeBundleTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x2::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcTubeBundleTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcTubeBundle::declaration() const { return *IFC4X2_IfcTubeBundle_type; }
@@ -20909,9 +20909,9 @@ Ifc4x2::IfcTubeBundleType::IfcTubeBundleType(std::string v1_GlobalId, ::Ifc4x2::
 
 // Function implementations for IfcTypeObject
 boost::optional< std::string > Ifc4x2::IfcTypeObject::ApplicableOccurrence() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcPropertySetDefinition >::ptr > Ifc4x2::IfcTypeObject::HasPropertySets() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x2::IfcPropertySetDefinition >(); }
-void Ifc4x2::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x2::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(5,attr);} }
+void Ifc4x2::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x2::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(5,attr);} }
 
 ::Ifc4x2::IfcRelDefinesByType::list::ptr Ifc4x2::IfcTypeObject::Types() const { return data_->getInverse(IFC4X2_IfcRelDefinesByType_type, 5)->as<IfcRelDefinesByType>(); }
 
@@ -20922,11 +20922,11 @@ Ifc4x2::IfcTypeObject::IfcTypeObject(std::string v1_GlobalId, ::Ifc4x2::IfcOwner
 
 // Function implementations for IfcTypeProcess
 boost::optional< std::string > Ifc4x2::IfcTypeProcess::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTypeProcess::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTypeProcess::ProcessType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x2::IfcRelAssignsToProcess::list::ptr Ifc4x2::IfcTypeProcess::OperatesOn() const { return data_->getInverse(IFC4X2_IfcRelAssignsToProcess_type, 6)->as<IfcRelAssignsToProcess>(); }
 
@@ -20937,9 +20937,9 @@ Ifc4x2::IfcTypeProcess::IfcTypeProcess(std::string v1_GlobalId, ::Ifc4x2::IfcOwn
 
 // Function implementations for IfcTypeProduct
 boost::optional< aggregate_of< ::Ifc4x2::IfcRepresentationMap >::ptr > Ifc4x2::IfcTypeProduct::RepresentationMaps() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x2::IfcRepresentationMap >(); }
-void Ifc4x2::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x2::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x2::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x2::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTypeProduct::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x2::IfcRelAssignsToProduct::list::ptr Ifc4x2::IfcTypeProduct::ReferencedBy() const { return data_->getInverse(IFC4X2_IfcRelAssignsToProduct_type, 6)->as<IfcRelAssignsToProduct>(); }
 
@@ -20950,11 +20950,11 @@ Ifc4x2::IfcTypeProduct::IfcTypeProduct(std::string v1_GlobalId, ::Ifc4x2::IfcOwn
 
 // Function implementations for IfcTypeResource
 boost::optional< std::string > Ifc4x2::IfcTypeResource::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTypeResource::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcTypeResource::ResourceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x2::IfcRelAssignsToResource::list::ptr Ifc4x2::IfcTypeResource::ResourceOf() const { return data_->getInverse(IFC4X2_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -20973,11 +20973,11 @@ void Ifc4x2::IfcUShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc4x2::IfcUShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x2::IfcUShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcUShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcUShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x2::IfcUShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcUShapeProfileDef::declaration() const { return *IFC4X2_IfcUShapeProfileDef_type; }
@@ -20997,7 +20997,7 @@ Ifc4x2::IfcUnitAssignment::IfcUnitAssignment(aggregate_of_instance::ptr v1_Units
 
 // Function implementations for IfcUnitaryControlElement
 boost::optional< ::Ifc4x2::IfcUnitaryControlElementTypeEnum::Value > Ifc4x2::IfcUnitaryControlElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcUnitaryControlElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcUnitaryControlElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x2::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcUnitaryControlElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcUnitaryControlElement::declaration() const { return *IFC4X2_IfcUnitaryControlElement_type; }
@@ -21017,7 +21017,7 @@ Ifc4x2::IfcUnitaryControlElementType::IfcUnitaryControlElementType(std::string v
 
 // Function implementations for IfcUnitaryEquipment
 boost::optional< ::Ifc4x2::IfcUnitaryEquipmentTypeEnum::Value > Ifc4x2::IfcUnitaryEquipment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcUnitaryEquipmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x2::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcUnitaryEquipmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x2::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcUnitaryEquipmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcUnitaryEquipment::declaration() const { return *IFC4X2_IfcUnitaryEquipment_type; }
@@ -21037,7 +21037,7 @@ Ifc4x2::IfcUnitaryEquipmentType::IfcUnitaryEquipmentType(std::string v1_GlobalId
 
 // Function implementations for IfcValve
 boost::optional< ::Ifc4x2::IfcValveTypeEnum::Value > Ifc4x2::IfcValve::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcValveTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcValve::setPredefinedType(boost::optional< ::Ifc4x2::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcValveTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcValve::setPredefinedType(boost::optional< ::Ifc4x2::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcValveTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcValve::declaration() const { return *IFC4X2_IfcValve_type; }
@@ -21097,7 +21097,7 @@ Ifc4x2::IfcVertexPoint::IfcVertexPoint(::Ifc4x2::IfcPoint* v1_VertexGeometry) :
 
 // Function implementations for IfcVibrationDamper
 boost::optional< ::Ifc4x2::IfcVibrationDamperTypeEnum::Value > Ifc4x2::IfcVibrationDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcVibrationDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcVibrationDamper::setPredefinedType(boost::optional< ::Ifc4x2::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcVibrationDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcVibrationDamper::setPredefinedType(boost::optional< ::Ifc4x2::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcVibrationDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcVibrationDamper::declaration() const { return *IFC4X2_IfcVibrationDamper_type; }
@@ -21107,7 +21107,7 @@ Ifc4x2::IfcVibrationDamper::IfcVibrationDamper(std::string v1_GlobalId, ::Ifc4x2
 
 // Function implementations for IfcVibrationDamperType
 boost::optional< ::Ifc4x2::IfcVibrationDamperTypeEnum::Value > Ifc4x2::IfcVibrationDamperType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x2::IfcVibrationDamperTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x2::IfcVibrationDamperType::setPredefinedType(boost::optional< ::Ifc4x2::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcVibrationDamperTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x2::IfcVibrationDamperType::setPredefinedType(boost::optional< ::Ifc4x2::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcVibrationDamperTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcVibrationDamperType::declaration() const { return *IFC4X2_IfcVibrationDamperType_type; }
@@ -21117,7 +21117,7 @@ Ifc4x2::IfcVibrationDamperType::IfcVibrationDamperType(std::string v1_GlobalId,
 
 // Function implementations for IfcVibrationIsolator
 boost::optional< ::Ifc4x2::IfcVibrationIsolatorTypeEnum::Value > Ifc4x2::IfcVibrationIsolator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcVibrationIsolatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x2::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcVibrationIsolatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x2::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcVibrationIsolatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcVibrationIsolator::declaration() const { return *IFC4X2_IfcVibrationIsolator_type; }
@@ -21157,7 +21157,7 @@ Ifc4x2::IfcVirtualGridIntersection::IfcVirtualGridIntersection(aggregate_of< ::I
 
 // Function implementations for IfcVoidingFeature
 boost::optional< ::Ifc4x2::IfcVoidingFeatureTypeEnum::Value > Ifc4x2::IfcVoidingFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcVoidingFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x2::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcVoidingFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x2::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcVoidingFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcVoidingFeature::declaration() const { return *IFC4X2_IfcVoidingFeature_type; }
@@ -21167,7 +21167,7 @@ Ifc4x2::IfcVoidingFeature::IfcVoidingFeature(std::string v1_GlobalId, ::Ifc4x2::
 
 // Function implementations for IfcWall
 boost::optional< ::Ifc4x2::IfcWallTypeEnum::Value > Ifc4x2::IfcWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcWall::setPredefinedType(boost::optional< ::Ifc4x2::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcWall::setPredefinedType(boost::optional< ::Ifc4x2::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcWall::declaration() const { return *IFC4X2_IfcWall_type; }
@@ -21203,7 +21203,7 @@ Ifc4x2::IfcWallType::IfcWallType(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHist
 
 // Function implementations for IfcWasteTerminal
 boost::optional< ::Ifc4x2::IfcWasteTerminalTypeEnum::Value > Ifc4x2::IfcWasteTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcWasteTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x2::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWasteTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x2::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWasteTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcWasteTerminal::declaration() const { return *IFC4X2_IfcWasteTerminal_type; }
@@ -21223,15 +21223,15 @@ Ifc4x2::IfcWasteTerminalType::IfcWasteTerminalType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcWindow
 boost::optional< double > Ifc4x2::IfcWindow::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x2::IfcWindow::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x2::IfcWindowTypeEnum::Value > Ifc4x2::IfcWindow::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x2::IfcWindowTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x2::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x2::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWindowTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x2::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x2::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWindowTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x2::IfcWindowTypePartitioningEnum::Value > Ifc4x2::IfcWindow::PartitioningType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x2::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x2::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x2::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWindowTypePartitioningEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x2::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x2::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWindowTypePartitioningEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x2::IfcWindow::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcWindow::declaration() const { return *IFC4X2_IfcWindow_type; }
@@ -21241,29 +21241,29 @@ Ifc4x2::IfcWindow::IfcWindow(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHistory*
 
 // Function implementations for IfcWindowLiningProperties
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::TransomThickness() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::MullionThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::FirstTransomOffset() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::SecondTransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::FirstMullionOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::SecondMullionOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 ::Ifc4x2::IfcShapeAspect* Ifc4x2::IfcWindowLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(12)))->as<::Ifc4x2::IfcShapeAspect>(true); }
 void Ifc4x2::IfcWindowLiningProperties::setShapeAspectStyle(::Ifc4x2::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::LiningOffset() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x2::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x2::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcWindowLiningProperties::declaration() const { return *IFC4X2_IfcWindowLiningProperties_type; }
@@ -21277,9 +21277,9 @@ void Ifc4x2::IfcWindowPanelProperties::setOperationType(::Ifc4x2::IfcWindowPanel
 ::Ifc4x2::IfcWindowPanelPositionEnum::Value Ifc4x2::IfcWindowPanelProperties::PanelPosition() const {  return ::Ifc4x2::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x2::IfcWindowPanelProperties::setPanelPosition(::Ifc4x2::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowPanelProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x2::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x2::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcWindowPanelProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x2::IfcShapeAspect* Ifc4x2::IfcWindowPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x2::IfcShapeAspect>(true); }
 void Ifc4x2::IfcWindowPanelProperties::setShapeAspectStyle(::Ifc4x2::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -21319,9 +21319,9 @@ void Ifc4x2::IfcWindowType::setPredefinedType(::Ifc4x2::IfcWindowTypeEnum::Value
 ::Ifc4x2::IfcWindowTypePartitioningEnum::Value Ifc4x2::IfcWindowType::PartitioningType() const {  return ::Ifc4x2::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x2::IfcWindowType::setPartitioningType(::Ifc4x2::IfcWindowTypePartitioningEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x2::IfcWindowTypePartitioningEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x2::IfcWindowType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x2::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x2::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x2::IfcWindowType::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcWindowType::declaration() const { return *IFC4X2_IfcWindowType_type; }
@@ -21331,11 +21331,11 @@ Ifc4x2::IfcWindowType::IfcWindowType(std::string v1_GlobalId, ::Ifc4x2::IfcOwner
 
 // Function implementations for IfcWorkCalendar
 boost::optional< aggregate_of< ::Ifc4x2::IfcWorkTime >::ptr > Ifc4x2::IfcWorkCalendar::WorkingTimes() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x2::IfcWorkTime >(); }
-void Ifc4x2::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x2::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x2::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x2::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcWorkTime >::ptr > Ifc4x2::IfcWorkCalendar::ExceptionTimes() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x2::IfcWorkTime >(); }
-void Ifc4x2::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x2::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x2::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x2::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x2::IfcWorkCalendarTypeEnum::Value > Ifc4x2::IfcWorkCalendar::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x2::IfcWorkCalendarTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x2::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x2::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWorkCalendarTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x2::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x2::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWorkCalendarTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcWorkCalendar::declaration() const { return *IFC4X2_IfcWorkCalendar_type; }
@@ -21347,17 +21347,17 @@ Ifc4x2::IfcWorkCalendar::IfcWorkCalendar(std::string v1_GlobalId, ::Ifc4x2::IfcO
 std::string Ifc4x2::IfcWorkControl::CreationDate() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x2::IfcWorkControl::setCreationDate(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x2::IfcPerson >::ptr > Ifc4x2::IfcWorkControl::Creators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x2::IfcPerson >(); }
-void Ifc4x2::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x2::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x2::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x2::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x2::IfcWorkControl::Purpose() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x2::IfcWorkControl::Duration() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x2::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x2::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x2::IfcWorkControl::TotalFloat() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x2::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x2::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 std::string Ifc4x2::IfcWorkControl::StartTime() const {  std::string v = *data_->getArgument(11); return v; }
 void Ifc4x2::IfcWorkControl::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x2::IfcWorkControl::FinishTime() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x2::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x2::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcWorkControl::declaration() const { return *IFC4X2_IfcWorkControl_type; }
@@ -21367,7 +21367,7 @@ Ifc4x2::IfcWorkControl::IfcWorkControl(std::string v1_GlobalId, ::Ifc4x2::IfcOwn
 
 // Function implementations for IfcWorkPlan
 boost::optional< ::Ifc4x2::IfcWorkPlanTypeEnum::Value > Ifc4x2::IfcWorkPlan::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x2::IfcWorkPlanTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x2::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x2::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWorkPlanTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x2::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x2::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWorkPlanTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcWorkPlan::declaration() const { return *IFC4X2_IfcWorkPlan_type; }
@@ -21377,7 +21377,7 @@ Ifc4x2::IfcWorkPlan::IfcWorkPlan(std::string v1_GlobalId, ::Ifc4x2::IfcOwnerHist
 
 // Function implementations for IfcWorkSchedule
 boost::optional< ::Ifc4x2::IfcWorkScheduleTypeEnum::Value > Ifc4x2::IfcWorkSchedule::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x2::IfcWorkScheduleTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x2::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x2::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWorkScheduleTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x2::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x2::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x2::IfcWorkScheduleTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcWorkSchedule::declaration() const { return *IFC4X2_IfcWorkSchedule_type; }
@@ -21389,9 +21389,9 @@ Ifc4x2::IfcWorkSchedule::IfcWorkSchedule(std::string v1_GlobalId, ::Ifc4x2::IfcO
 ::Ifc4x2::IfcRecurrencePattern* Ifc4x2::IfcWorkTime::RecurrencePattern() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x2::IfcRecurrencePattern>(true); }
 void Ifc4x2::IfcWorkTime::setRecurrencePattern(::Ifc4x2::IfcRecurrencePattern* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x2::IfcWorkTime::Start() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x2::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x2::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x2::IfcWorkTime::Finish() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcWorkTime::declaration() const { return *IFC4X2_IfcWorkTime_type; }
@@ -21409,9 +21409,9 @@ void Ifc4x2::IfcZShapeProfileDef::setWebThickness(double v) { {IfcWrite::IfcWrit
 double Ifc4x2::IfcZShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x2::IfcZShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x2::IfcZShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x2::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x2::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x2::IfcZShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x2::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x2::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcZShapeProfileDef::declaration() const { return *IFC4X2_IfcZShapeProfileDef_type; }
@@ -21421,7 +21421,7 @@ Ifc4x2::IfcZShapeProfileDef::IfcZShapeProfileDef(::Ifc4x2::IfcProfileTypeEnum::V
 
 // Function implementations for IfcZone
 boost::optional< std::string > Ifc4x2::IfcZone::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x2::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x2::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x2::IfcZone::declaration() const { return *IFC4X2_IfcZone_type; }
diff --git a/src/ifcparse/Ifc4x3_rc1.cpp b/src/ifcparse/Ifc4x3_rc1.cpp
index 67bc0c0e19..03437fc88e 100644
--- a/src/ifcparse/Ifc4x3_rc1.cpp
+++ b/src/ifcparse/Ifc4x3_rc1.cpp
@@ -12962,11 +12962,11 @@ Ifc4x3_rc1::IfcWarpingMomentMeasure::operator double() const { return *data_->ge
 
 // Function implementations for IfcActionRequest
 boost::optional< ::Ifc4x3_rc1::IfcActionRequestTypeEnum::Value > Ifc4x3_rc1::IfcActionRequest::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcActionRequestTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc1::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcActionRequestTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcActionRequestTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcActionRequest::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcActionRequest::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcActionRequest::declaration() const { return *IFC4X3_RC1_IfcActionRequest_type; }
@@ -12989,9 +12989,9 @@ Ifc4x3_rc1::IfcActor::IfcActor(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHi
 ::Ifc4x3_rc1::IfcRoleEnum::Value Ifc4x3_rc1::IfcActorRole::Role() const {  return ::Ifc4x3_rc1::IfcRoleEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc1::IfcActorRole::setRole(::Ifc4x3_rc1::IfcRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcRoleEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcActorRole::UserDefinedRole() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcActorRole::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc1::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc1::IfcActorRole::HasExternalReference() const { return data_->getInverse(IFC4X3_RC1_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -13002,7 +13002,7 @@ Ifc4x3_rc1::IfcActorRole::IfcActorRole(::Ifc4x3_rc1::IfcRoleEnum::Value v1_Role,
 
 // Function implementations for IfcActuator
 boost::optional< ::Ifc4x3_rc1::IfcActuatorTypeEnum::Value > Ifc4x3_rc1::IfcActuator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcActuatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcActuatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcActuatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcActuator::declaration() const { return *IFC4X3_RC1_IfcActuator_type; }
@@ -13022,11 +13022,11 @@ Ifc4x3_rc1::IfcActuatorType::IfcActuatorType(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcAddress
 boost::optional< ::Ifc4x3_rc1::IfcAddressTypeEnum::Value > Ifc4x3_rc1::IfcAddress::Purpose() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcAddressTypeEnum::FromString(*data_->getArgument(0)); }
-void Ifc4x3_rc1::IfcAddress::setPurpose(boost::optional< ::Ifc4x3_rc1::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAddressTypeEnum::ToString(*v)));data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcAddress::setPurpose(boost::optional< ::Ifc4x3_rc1::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAddressTypeEnum::ToString(*v)));}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAddress::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAddress::UserDefinedPurpose() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc1::IfcPerson::list::ptr Ifc4x3_rc1::IfcAddress::OfPerson() const { return data_->getInverse(IFC4X3_RC1_IfcPerson_type, 7)->as<IfcPerson>(); }
 ::Ifc4x3_rc1::IfcOrganization::list::ptr Ifc4x3_rc1::IfcAddress::OfOrganization() const { return data_->getInverse(IFC4X3_RC1_IfcOrganization_type, 4)->as<IfcOrganization>(); }
@@ -13064,7 +13064,7 @@ Ifc4x3_rc1::IfcAdvancedFace::IfcAdvancedFace(aggregate_of< ::Ifc4x3_rc1::IfcFace
 
 // Function implementations for IfcAirTerminal
 boost::optional< ::Ifc4x3_rc1::IfcAirTerminalTypeEnum::Value > Ifc4x3_rc1::IfcAirTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcAirTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAirTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAirTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcAirTerminal::declaration() const { return *IFC4X3_RC1_IfcAirTerminal_type; }
@@ -13074,7 +13074,7 @@ Ifc4x3_rc1::IfcAirTerminal::IfcAirTerminal(std::string v1_GlobalId, ::Ifc4x3_rc1
 
 // Function implementations for IfcAirTerminalBox
 boost::optional< ::Ifc4x3_rc1::IfcAirTerminalBoxTypeEnum::Value > Ifc4x3_rc1::IfcAirTerminalBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcAirTerminalBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAirTerminalBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAirTerminalBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcAirTerminalBox::declaration() const { return *IFC4X3_RC1_IfcAirTerminalBox_type; }
@@ -13104,7 +13104,7 @@ Ifc4x3_rc1::IfcAirTerminalType::IfcAirTerminalType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcAirToAirHeatRecovery
 boost::optional< ::Ifc4x3_rc1::IfcAirToAirHeatRecoveryTypeEnum::Value > Ifc4x3_rc1::IfcAirToAirHeatRecovery::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcAirToAirHeatRecoveryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcAirToAirHeatRecovery::declaration() const { return *IFC4X3_RC1_IfcAirToAirHeatRecovery_type; }
@@ -13124,7 +13124,7 @@ Ifc4x3_rc1::IfcAirToAirHeatRecoveryType::IfcAirToAirHeatRecoveryType(std::string
 
 // Function implementations for IfcAlarm
 boost::optional< ::Ifc4x3_rc1::IfcAlarmTypeEnum::Value > Ifc4x3_rc1::IfcAlarm::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcAlarmTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAlarmTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAlarmTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcAlarm::declaration() const { return *IFC4X3_RC1_IfcAlarm_type; }
@@ -13144,7 +13144,7 @@ Ifc4x3_rc1::IfcAlarmType::IfcAlarmType(std::string v1_GlobalId, ::Ifc4x3_rc1::If
 
 // Function implementations for IfcAlignment
 boost::optional< ::Ifc4x3_rc1::IfcAlignmentTypeEnum::Value > Ifc4x3_rc1::IfcAlignment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcAlignmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAlignmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAlignmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcAlignment::declaration() const { return *IFC4X3_RC1_IfcAlignment_type; }
@@ -13174,9 +13174,9 @@ Ifc4x3_rc1::IfcAlignment2DCantSegLine::IfcAlignment2DCantSegLine(boost::optional
 
 // Function implementations for IfcAlignment2DCantSegTransition
 boost::optional< double > Ifc4x3_rc1::IfcAlignment2DCantSegTransition::StartRadius() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcAlignment2DCantSegTransition::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcAlignment2DCantSegTransition::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAlignment2DCantSegTransition::EndRadius() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcAlignment2DCantSegTransition::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcAlignment2DCantSegTransition::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 bool Ifc4x3_rc1::IfcAlignment2DCantSegTransition::IsStartRadiusCCW() const {  bool v = *data_->getArgument(11); return v; }
 void Ifc4x3_rc1::IfcAlignment2DCantSegTransition::setIsStartRadiusCCW(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 bool Ifc4x3_rc1::IfcAlignment2DCantSegTransition::IsEndRadiusCCW() const {  bool v = *data_->getArgument(12); return v; }
@@ -13198,11 +13198,11 @@ void Ifc4x3_rc1::IfcAlignment2DCantSegment::setHorizontalLength(double v) { {Ifc
 double Ifc4x3_rc1::IfcAlignment2DCantSegment::StartCantLeft() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc1::IfcAlignment2DCantSegment::setStartCantLeft(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAlignment2DCantSegment::EndCantLeft() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcAlignment2DCantSegment::setEndCantLeft(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcAlignment2DCantSegment::setEndCantLeft(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 double Ifc4x3_rc1::IfcAlignment2DCantSegment::StartCantRight() const {  double v = *data_->getArgument(7); return v; }
 void Ifc4x3_rc1::IfcAlignment2DCantSegment::setStartCantRight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAlignment2DCantSegment::EndCantRight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcAlignment2DCantSegment::setEndCantRight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcAlignment2DCantSegment::setEndCantRight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc1::IfcAlignment2DCant::list::ptr Ifc4x3_rc1::IfcAlignment2DCantSegment::ToCant() const { return data_->getInverse(IFC4X3_RC1_IfcAlignment2DCant_type, 0)->as<IfcAlignment2DCant>(); }
 
@@ -13213,7 +13213,7 @@ Ifc4x3_rc1::IfcAlignment2DCantSegment::IfcAlignment2DCantSegment(boost::optional
 
 // Function implementations for IfcAlignment2DHorizontal
 boost::optional< double > Ifc4x3_rc1::IfcAlignment2DHorizontal::StartDistAlong() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcAlignment2DHorizontal::setStartDistAlong(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcAlignment2DHorizontal::setStartDistAlong(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc4x3_rc1::IfcAlignment2DHorizontalSegment >::ptr Ifc4x3_rc1::IfcAlignment2DHorizontal::Segments() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc1::IfcAlignment2DHorizontalSegment >(); }
 void Ifc4x3_rc1::IfcAlignment2DHorizontal::setSegments(aggregate_of< ::Ifc4x3_rc1::IfcAlignment2DHorizontalSegment >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -13237,11 +13237,11 @@ Ifc4x3_rc1::IfcAlignment2DHorizontalSegment::IfcAlignment2DHorizontalSegment(boo
 
 // Function implementations for IfcAlignment2DSegment
 boost::optional< bool > Ifc4x3_rc1::IfcAlignment2DSegment::TangentialContinuity() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } bool v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcAlignment2DSegment::setTangentialContinuity(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcAlignment2DSegment::setTangentialContinuity(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAlignment2DSegment::StartTag() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcAlignment2DSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcAlignment2DSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAlignment2DSegment::EndTag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcAlignment2DSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcAlignment2DSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcAlignment2DSegment::declaration() const { return *IFC4X3_RC1_IfcAlignment2DSegment_type; }
@@ -13283,9 +13283,9 @@ Ifc4x3_rc1::IfcAlignment2DVerSegParabolicArc::IfcAlignment2DVerSegParabolicArc(b
 
 // Function implementations for IfcAlignment2DVerSegTransition
 boost::optional< double > Ifc4x3_rc1::IfcAlignment2DVerSegTransition::StartRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcAlignment2DVerSegTransition::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcAlignment2DVerSegTransition::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAlignment2DVerSegTransition::EndRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcAlignment2DVerSegTransition::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcAlignment2DVerSegTransition::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 bool Ifc4x3_rc1::IfcAlignment2DVerSegTransition::IsStartRadiusCCW() const {  bool v = *data_->getArgument(9); return v; }
 void Ifc4x3_rc1::IfcAlignment2DVerSegTransition::setIsStartRadiusCCW(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 bool Ifc4x3_rc1::IfcAlignment2DVerSegTransition::IsEndRadiusCCW() const {  bool v = *data_->getArgument(10); return v; }
@@ -13333,7 +13333,7 @@ void Ifc4x3_rc1::IfcAlignmentCurve::setHorizontal(::Ifc4x3_rc1::IfcAlignment2DHo
 ::Ifc4x3_rc1::IfcAlignment2DVertical* Ifc4x3_rc1::IfcAlignmentCurve::Vertical() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc1::IfcAlignment2DVertical>(true); }
 void Ifc4x3_rc1::IfcAlignmentCurve::setVertical(::Ifc4x3_rc1::IfcAlignment2DVertical* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAlignmentCurve::Tag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcAlignmentCurve::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcAlignmentCurve::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcAlignmentCurve::declaration() const { return *IFC4X3_RC1_IfcAlignmentCurve_type; }
@@ -13343,7 +13343,7 @@ Ifc4x3_rc1::IfcAlignmentCurve::IfcAlignmentCurve(::Ifc4x3_rc1::IfcAlignment2DHor
 
 // Function implementations for IfcAnnotation
 boost::optional< ::Ifc4x3_rc1::IfcAnnotationTypeEnum::Value > Ifc4x3_rc1::IfcAnnotation::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcAnnotationTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc1::IfcAnnotation::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAnnotationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAnnotationTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcAnnotation::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAnnotationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAnnotationTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc1::IfcRelContainedInSpatialStructure::list::ptr Ifc4x3_rc1::IfcAnnotation::ContainedInStructure() const { return data_->getInverse(IFC4X3_RC1_IfcRelContainedInSpatialStructure_type, 4)->as<IfcRelContainedInSpatialStructure>(); }
 
@@ -13356,7 +13356,7 @@ Ifc4x3_rc1::IfcAnnotation::IfcAnnotation(std::string v1_GlobalId, ::Ifc4x3_rc1::
 ::Ifc4x3_rc1::IfcCurve* Ifc4x3_rc1::IfcAnnotationFillArea::OuterBoundary() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc1::IfcCurve>(true); }
 void Ifc4x3_rc1::IfcAnnotationFillArea::setOuterBoundary(::Ifc4x3_rc1::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcCurve >::ptr > Ifc4x3_rc1::IfcAnnotationFillArea::InnerBoundaries() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc1::IfcCurve >(); }
-void Ifc4x3_rc1::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcAnnotationFillArea::declaration() const { return *IFC4X3_RC1_IfcAnnotationFillArea_type; }
@@ -13382,25 +13382,25 @@ Ifc4x3_rc1::IfcApplication::IfcApplication(::Ifc4x3_rc1::IfcOrganization* v1_App
 
 // Function implementations for IfcAppliedValue
 boost::optional< std::string > Ifc4x3_rc1::IfcAppliedValue::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAppliedValue::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc1::IfcAppliedValueSelect* Ifc4x3_rc1::IfcAppliedValue::AppliedValue() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc1::IfcAppliedValueSelect>(true); }
 void Ifc4x3_rc1::IfcAppliedValue::setAppliedValue(::Ifc4x3_rc1::IfcAppliedValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcMeasureWithUnit* Ifc4x3_rc1::IfcAppliedValue::UnitBasis() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcMeasureWithUnit>(true); }
 void Ifc4x3_rc1::IfcAppliedValue::setUnitBasis(::Ifc4x3_rc1::IfcMeasureWithUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAppliedValue::ApplicableDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAppliedValue::FixedUntilDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAppliedValue::Category() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAppliedValue::Condition() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcArithmeticOperatorEnum::Value > Ifc4x3_rc1::IfcAppliedValue::ArithmeticOperator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcArithmeticOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x3_rc1::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcArithmeticOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x3_rc1::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcArithmeticOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAppliedValue >::ptr > Ifc4x3_rc1::IfcAppliedValue::Components() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc1::IfcAppliedValue >(); }
-void Ifc4x3_rc1::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 
 ::Ifc4x3_rc1::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc1::IfcAppliedValue::HasExternalReference() const { return data_->getInverse(IFC4X3_RC1_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -13411,19 +13411,19 @@ Ifc4x3_rc1::IfcAppliedValue::IfcAppliedValue(boost::optional< std::string > v1_N
 
 // Function implementations for IfcApproval
 boost::optional< std::string > Ifc4x3_rc1::IfcApproval::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcApproval::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcApproval::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcApproval::TimeOfApproval() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcApproval::Status() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcApproval::Level() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcApproval::Qualifier() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc1::IfcActorSelect* Ifc4x3_rc1::IfcApproval::RequestingApproval() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc1::IfcActorSelect>(true); }
 void Ifc4x3_rc1::IfcApproval::setRequestingApproval(::Ifc4x3_rc1::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x3_rc1::IfcActorSelect* Ifc4x3_rc1::IfcApproval::GivingApproval() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc1::IfcActorSelect>(true); }
@@ -13484,7 +13484,7 @@ Ifc4x3_rc1::IfcArbitraryProfileDefWithVoids::IfcArbitraryProfileDefWithVoids(::I
 
 // Function implementations for IfcAsset
 boost::optional< std::string > Ifc4x3_rc1::IfcAsset::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc1::IfcCostValue* Ifc4x3_rc1::IfcAsset::OriginalValue() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcCostValue>(true); }
 void Ifc4x3_rc1::IfcAsset::setOriginalValue(::Ifc4x3_rc1::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 ::Ifc4x3_rc1::IfcCostValue* Ifc4x3_rc1::IfcAsset::CurrentValue() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc1::IfcCostValue>(true); }
@@ -13498,7 +13498,7 @@ void Ifc4x3_rc1::IfcAsset::setUser(::Ifc4x3_rc1::IfcActorSelect* v) { {IfcWrite:
 ::Ifc4x3_rc1::IfcPerson* Ifc4x3_rc1::IfcAsset::ResponsiblePerson() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc1::IfcPerson>(true); }
 void Ifc4x3_rc1::IfcAsset::setResponsiblePerson(::Ifc4x3_rc1::IfcPerson* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcAsset::IncorporationDate() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x3_rc1::IfcCostValue* Ifc4x3_rc1::IfcAsset::DepreciatedValue() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x3_rc1::IfcCostValue>(true); }
 void Ifc4x3_rc1::IfcAsset::setDepreciatedValue(::Ifc4x3_rc1::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -13518,21 +13518,21 @@ void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setWebThickness(double v) { {Ifc
 double Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::BottomFlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setBottomFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::BottomFlangeFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 double Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::TopFlangeWidth() const {  double v = *data_->getArgument(8); return v; }
 void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setTopFlangeWidth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::TopFlangeThickness() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::TopFlangeFilletRadius() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::BottomFlangeEdgeRadius() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::BottomFlangeSlope() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::TopFlangeEdgeRadius() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::TopFlangeSlope() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::declaration() const { return *IFC4X3_RC1_IfcAsymmetricIShapeProfileDef_type; }
@@ -13542,7 +13542,7 @@ Ifc4x3_rc1::IfcAsymmetricIShapeProfileDef::IfcAsymmetricIShapeProfileDef(::Ifc4x
 
 // Function implementations for IfcAudioVisualAppliance
 boost::optional< ::Ifc4x3_rc1::IfcAudioVisualApplianceTypeEnum::Value > Ifc4x3_rc1::IfcAudioVisualAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcAudioVisualApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAudioVisualApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAudioVisualApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcAudioVisualAppliance::declaration() const { return *IFC4X3_RC1_IfcAudioVisualAppliance_type; }
@@ -13675,7 +13675,7 @@ Ifc4x3_rc1::IfcBSplineSurfaceWithKnots::IfcBSplineSurfaceWithKnots(int v1_UDegre
 
 // Function implementations for IfcBeam
 boost::optional< ::Ifc4x3_rc1::IfcBeamTypeEnum::Value > Ifc4x3_rc1::IfcBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBeam::declaration() const { return *IFC4X3_RC1_IfcBeam_type; }
@@ -13703,7 +13703,7 @@ Ifc4x3_rc1::IfcBeamType::IfcBeamType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcBearing
 boost::optional< ::Ifc4x3_rc1::IfcBearingTypeEnum::Value > Ifc4x3_rc1::IfcBearing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcBearingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcBearing::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBearingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBearingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcBearing::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBearingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBearingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBearing::declaration() const { return *IFC4X3_RC1_IfcBearing_type; }
@@ -13749,7 +13749,7 @@ Ifc4x3_rc1::IfcBlock::IfcBlock(::Ifc4x3_rc1::IfcAxis2Placement3D* v1_Position, d
 
 // Function implementations for IfcBoiler
 boost::optional< ::Ifc4x3_rc1::IfcBoilerTypeEnum::Value > Ifc4x3_rc1::IfcBoiler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcBoilerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBoilerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBoilerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBoiler::declaration() const { return *IFC4X3_RC1_IfcBoiler_type; }
@@ -13799,7 +13799,7 @@ Ifc4x3_rc1::IfcBorehole::IfcBorehole(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcBoundaryCondition
 boost::optional< std::string > Ifc4x3_rc1::IfcBoundaryCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBoundaryCondition::declaration() const { return *IFC4X3_RC1_IfcBoundaryCondition_type; }
@@ -13924,7 +13924,7 @@ Ifc4x3_rc1::IfcBoxedHalfSpace::IfcBoxedHalfSpace(::Ifc4x3_rc1::IfcSurface* v1_Ba
 
 // Function implementations for IfcBridge
 boost::optional< ::Ifc4x3_rc1::IfcBridgeTypeEnum::Value > Ifc4x3_rc1::IfcBridge::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcBridgeTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc1::IfcBridge::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBridgeTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBridgeTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcBridge::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBridgeTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBridgeTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBridge::declaration() const { return *IFC4X3_RC1_IfcBridge_type; }
@@ -13942,9 +13942,9 @@ Ifc4x3_rc1::IfcBridgePart::IfcBridgePart(std::string v1_GlobalId, ::Ifc4x3_rc1::
 
 // Function implementations for IfcBuilding
 boost::optional< double > Ifc4x3_rc1::IfcBuilding::ElevationOfRefHeight() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcBuilding::ElevationOfTerrain() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc1::IfcPostalAddress* Ifc4x3_rc1::IfcBuilding::BuildingAddress() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc1::IfcPostalAddress>(true); }
 void Ifc4x3_rc1::IfcBuilding::setBuildingAddress(::Ifc4x3_rc1::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 
@@ -13956,7 +13956,7 @@ Ifc4x3_rc1::IfcBuilding::IfcBuilding(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcBuildingElementPart
 boost::optional< ::Ifc4x3_rc1::IfcBuildingElementPartTypeEnum::Value > Ifc4x3_rc1::IfcBuildingElementPart::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcBuildingElementPartTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBuildingElementPartTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBuildingElementPartTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBuildingElementPart::declaration() const { return *IFC4X3_RC1_IfcBuildingElementPart_type; }
@@ -13976,7 +13976,7 @@ Ifc4x3_rc1::IfcBuildingElementPartType::IfcBuildingElementPartType(std::string v
 
 // Function implementations for IfcBuildingElementProxy
 boost::optional< ::Ifc4x3_rc1::IfcBuildingElementProxyTypeEnum::Value > Ifc4x3_rc1::IfcBuildingElementProxy::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcBuildingElementProxyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBuildingElementProxyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBuildingElementProxyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBuildingElementProxy::declaration() const { return *IFC4X3_RC1_IfcBuildingElementProxy_type; }
@@ -13996,7 +13996,7 @@ Ifc4x3_rc1::IfcBuildingElementProxyType::IfcBuildingElementProxyType(std::string
 
 // Function implementations for IfcBuildingStorey
 boost::optional< double > Ifc4x3_rc1::IfcBuildingStorey::Elevation() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBuildingStorey::declaration() const { return *IFC4X3_RC1_IfcBuildingStorey_type; }
@@ -14006,9 +14006,9 @@ Ifc4x3_rc1::IfcBuildingStorey::IfcBuildingStorey(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcBuildingSystem
 boost::optional< ::Ifc4x3_rc1::IfcBuildingSystemTypeEnum::Value > Ifc4x3_rc1::IfcBuildingSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcBuildingSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc1::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBuildingSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBuildingSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcBuildingSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBuildingSystem::declaration() const { return *IFC4X3_RC1_IfcBuildingSystem_type; }
@@ -14034,9 +14034,9 @@ Ifc4x3_rc1::IfcBuiltElementType::IfcBuiltElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcBuiltSystem
 boost::optional< ::Ifc4x3_rc1::IfcBuiltSystemTypeEnum::Value > Ifc4x3_rc1::IfcBuiltSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcBuiltSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc1::IfcBuiltSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBuiltSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBuiltSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcBuiltSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBuiltSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBuiltSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcBuiltSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcBuiltSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcBuiltSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBuiltSystem::declaration() const { return *IFC4X3_RC1_IfcBuiltSystem_type; }
@@ -14046,7 +14046,7 @@ Ifc4x3_rc1::IfcBuiltSystem::IfcBuiltSystem(std::string v1_GlobalId, ::Ifc4x3_rc1
 
 // Function implementations for IfcBurner
 boost::optional< ::Ifc4x3_rc1::IfcBurnerTypeEnum::Value > Ifc4x3_rc1::IfcBurner::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcBurnerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBurnerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcBurnerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcBurner::declaration() const { return *IFC4X3_RC1_IfcBurner_type; }
@@ -14074,7 +14074,7 @@ void Ifc4x3_rc1::IfcCShapeProfileDef::setWallThickness(double v) { {IfcWrite::If
 double Ifc4x3_rc1::IfcCShapeProfileDef::Girth() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc1::IfcCShapeProfileDef::setGirth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcCShapeProfileDef::InternalFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCShapeProfileDef::declaration() const { return *IFC4X3_RC1_IfcCShapeProfileDef_type; }
@@ -14084,7 +14084,7 @@ Ifc4x3_rc1::IfcCShapeProfileDef::IfcCShapeProfileDef(::Ifc4x3_rc1::IfcProfileTyp
 
 // Function implementations for IfcCableCarrierFitting
 boost::optional< ::Ifc4x3_rc1::IfcCableCarrierFittingTypeEnum::Value > Ifc4x3_rc1::IfcCableCarrierFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCableCarrierFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCableCarrierFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCableCarrierFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCableCarrierFitting::declaration() const { return *IFC4X3_RC1_IfcCableCarrierFitting_type; }
@@ -14104,7 +14104,7 @@ Ifc4x3_rc1::IfcCableCarrierFittingType::IfcCableCarrierFittingType(std::string v
 
 // Function implementations for IfcCableCarrierSegment
 boost::optional< ::Ifc4x3_rc1::IfcCableCarrierSegmentTypeEnum::Value > Ifc4x3_rc1::IfcCableCarrierSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCableCarrierSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCableCarrierSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCableCarrierSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCableCarrierSegment::declaration() const { return *IFC4X3_RC1_IfcCableCarrierSegment_type; }
@@ -14124,7 +14124,7 @@ Ifc4x3_rc1::IfcCableCarrierSegmentType::IfcCableCarrierSegmentType(std::string v
 
 // Function implementations for IfcCableFitting
 boost::optional< ::Ifc4x3_rc1::IfcCableFittingTypeEnum::Value > Ifc4x3_rc1::IfcCableFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCableFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCableFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCableFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCableFitting::declaration() const { return *IFC4X3_RC1_IfcCableFitting_type; }
@@ -14144,7 +14144,7 @@ Ifc4x3_rc1::IfcCableFittingType::IfcCableFittingType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcCableSegment
 boost::optional< ::Ifc4x3_rc1::IfcCableSegmentTypeEnum::Value > Ifc4x3_rc1::IfcCableSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCableSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCableSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCableSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCableSegment::declaration() const { return *IFC4X3_RC1_IfcCableSegment_type; }
@@ -14164,7 +14164,7 @@ Ifc4x3_rc1::IfcCableSegmentType::IfcCableSegmentType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcCaissonFoundation
 boost::optional< ::Ifc4x3_rc1::IfcCaissonFoundationTypeEnum::Value > Ifc4x3_rc1::IfcCaissonFoundation::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCaissonFoundationTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCaissonFoundation::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCaissonFoundationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCaissonFoundationTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCaissonFoundation::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCaissonFoundationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCaissonFoundationTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCaissonFoundation::declaration() const { return *IFC4X3_RC1_IfcCaissonFoundation_type; }
@@ -14204,7 +14204,7 @@ Ifc4x3_rc1::IfcCartesianPointList::IfcCartesianPointList() : IfcGeometricReprese
 std::vector< std::vector< double > > Ifc4x3_rc1::IfcCartesianPointList2D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcCartesianPointList2D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcCartesianPointList2D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCartesianPointList2D::declaration() const { return *IFC4X3_RC1_IfcCartesianPointList2D_type; }
@@ -14216,7 +14216,7 @@ Ifc4x3_rc1::IfcCartesianPointList2D::IfcCartesianPointList2D(std::vector< std::v
 std::vector< std::vector< double > > Ifc4x3_rc1::IfcCartesianPointList3D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcCartesianPointList3D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcCartesianPointList3D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCartesianPointList3D::declaration() const { return *IFC4X3_RC1_IfcCartesianPointList3D_type; }
@@ -14232,7 +14232,7 @@ void Ifc4x3_rc1::IfcCartesianTransformationOperator::setAxis2(::Ifc4x3_rc1::IfcD
 ::Ifc4x3_rc1::IfcCartesianPoint* Ifc4x3_rc1::IfcCartesianTransformationOperator::LocalOrigin() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc1::IfcCartesianPoint>(true); }
 void Ifc4x3_rc1::IfcCartesianTransformationOperator::setLocalOrigin(::Ifc4x3_rc1::IfcCartesianPoint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcCartesianTransformationOperator::Scale() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCartesianTransformationOperator::declaration() const { return *IFC4X3_RC1_IfcCartesianTransformationOperator_type; }
@@ -14250,7 +14250,7 @@ Ifc4x3_rc1::IfcCartesianTransformationOperator2D::IfcCartesianTransformationOper
 
 // Function implementations for IfcCartesianTransformationOperator2DnonUniform
 boost::optional< double > Ifc4x3_rc1::IfcCartesianTransformationOperator2DnonUniform::Scale2() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCartesianTransformationOperator2DnonUniform::declaration() const { return *IFC4X3_RC1_IfcCartesianTransformationOperator2DnonUniform_type; }
@@ -14270,9 +14270,9 @@ Ifc4x3_rc1::IfcCartesianTransformationOperator3D::IfcCartesianTransformationOper
 
 // Function implementations for IfcCartesianTransformationOperator3DnonUniform
 boost::optional< double > Ifc4x3_rc1::IfcCartesianTransformationOperator3DnonUniform::Scale2() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcCartesianTransformationOperator3DnonUniform::Scale3() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCartesianTransformationOperator3DnonUniform::declaration() const { return *IFC4X3_RC1_IfcCartesianTransformationOperator3DnonUniform_type; }
@@ -14292,7 +14292,7 @@ Ifc4x3_rc1::IfcCenterLineProfileDef::IfcCenterLineProfileDef(::Ifc4x3_rc1::IfcPr
 
 // Function implementations for IfcChiller
 boost::optional< ::Ifc4x3_rc1::IfcChillerTypeEnum::Value > Ifc4x3_rc1::IfcChiller::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcChillerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcChillerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcChillerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcChiller::declaration() const { return *IFC4X3_RC1_IfcChiller_type; }
@@ -14312,7 +14312,7 @@ Ifc4x3_rc1::IfcChillerType::IfcChillerType(std::string v1_GlobalId, ::Ifc4x3_rc1
 
 // Function implementations for IfcChimney
 boost::optional< ::Ifc4x3_rc1::IfcChimneyTypeEnum::Value > Ifc4x3_rc1::IfcChimney::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcChimneyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcChimneyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcChimneyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcChimney::declaration() const { return *IFC4X3_RC1_IfcChimney_type; }
@@ -14390,19 +14390,19 @@ Ifc4x3_rc1::IfcCivilElementType::IfcCivilElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcClassification
 boost::optional< std::string > Ifc4x3_rc1::IfcClassification::Source() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcClassification::Edition() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcClassification::EditionDate() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::string Ifc4x3_rc1::IfcClassification::Name() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcClassification::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcClassification::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcClassification::Location() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcClassification::ReferenceTokens() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc1::IfcRelAssociatesClassification::list::ptr Ifc4x3_rc1::IfcClassification::ClassificationForObjects() const { return data_->getInverse(IFC4X3_RC1_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x3_rc1::IfcClassificationReference::list::ptr Ifc4x3_rc1::IfcClassification::HasReferences() const { return data_->getInverse(IFC4X3_RC1_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -14416,9 +14416,9 @@ Ifc4x3_rc1::IfcClassification::IfcClassification(boost::optional< std::string >
 ::Ifc4x3_rc1::IfcClassificationReferenceSelect* Ifc4x3_rc1::IfcClassificationReference::ReferencedSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcClassificationReferenceSelect>(true); }
 void Ifc4x3_rc1::IfcClassificationReference::setReferencedSource(::Ifc4x3_rc1::IfcClassificationReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcClassificationReference::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcClassificationReference::Sort() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc1::IfcRelAssociatesClassification::list::ptr Ifc4x3_rc1::IfcClassificationReference::ClassificationRefForObjects() const { return data_->getInverse(IFC4X3_RC1_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x3_rc1::IfcClassificationReference::list::ptr Ifc4x3_rc1::IfcClassificationReference::HasReferences() const { return data_->getInverse(IFC4X3_RC1_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -14438,7 +14438,7 @@ Ifc4x3_rc1::IfcClosedShell::IfcClosedShell(aggregate_of< ::Ifc4x3_rc1::IfcFace >
 
 // Function implementations for IfcCoil
 boost::optional< ::Ifc4x3_rc1::IfcCoilTypeEnum::Value > Ifc4x3_rc1::IfcCoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCoil::declaration() const { return *IFC4X3_RC1_IfcCoil_type; }
@@ -14482,7 +14482,7 @@ Ifc4x3_rc1::IfcColourRgbList::IfcColourRgbList(std::vector< std::vector< double
 
 // Function implementations for IfcColourSpecification
 boost::optional< std::string > Ifc4x3_rc1::IfcColourSpecification::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcColourSpecification::declaration() const { return *IFC4X3_RC1_IfcColourSpecification_type; }
@@ -14492,7 +14492,7 @@ Ifc4x3_rc1::IfcColourSpecification::IfcColourSpecification(boost::optional< std:
 
 // Function implementations for IfcColumn
 boost::optional< ::Ifc4x3_rc1::IfcColumnTypeEnum::Value > Ifc4x3_rc1::IfcColumn::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcColumnTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcColumnTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcColumnTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcColumn::declaration() const { return *IFC4X3_RC1_IfcColumn_type; }
@@ -14520,7 +14520,7 @@ Ifc4x3_rc1::IfcColumnType::IfcColumnType(std::string v1_GlobalId, ::Ifc4x3_rc1::
 
 // Function implementations for IfcCommunicationsAppliance
 boost::optional< ::Ifc4x3_rc1::IfcCommunicationsApplianceTypeEnum::Value > Ifc4x3_rc1::IfcCommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCommunicationsAppliance::declaration() const { return *IFC4X3_RC1_IfcCommunicationsAppliance_type; }
@@ -14552,11 +14552,11 @@ Ifc4x3_rc1::IfcComplexProperty::IfcComplexProperty(std::string v1_Name, boost::o
 
 // Function implementations for IfcComplexPropertyTemplate
 boost::optional< std::string > Ifc4x3_rc1::IfcComplexPropertyTemplate::UsageName() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcComplexPropertyTemplateTypeEnum::Value > Ifc4x3_rc1::IfcComplexPropertyTemplate::TemplateType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcComplexPropertyTemplateTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc1::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc1::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc1::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPropertyTemplate >::ptr > Ifc4x3_rc1::IfcComplexPropertyTemplate::HasPropertyTemplates() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc1::IfcPropertyTemplate >(); }
-void Ifc4x3_rc1::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcComplexPropertyTemplate::declaration() const { return *IFC4X3_RC1_IfcComplexPropertyTemplate_type; }
@@ -14603,7 +14603,7 @@ Ifc4x3_rc1::IfcCompositeCurveSegment::IfcCompositeCurveSegment(::Ifc4x3_rc1::Ifc
 aggregate_of< ::Ifc4x3_rc1::IfcProfileDef >::ptr Ifc4x3_rc1::IfcCompositeProfileDef::Profiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc1::IfcProfileDef >(); }
 void Ifc4x3_rc1::IfcCompositeProfileDef::setProfiles(aggregate_of< ::Ifc4x3_rc1::IfcProfileDef >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcCompositeProfileDef::Label() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCompositeProfileDef::declaration() const { return *IFC4X3_RC1_IfcCompositeProfileDef_type; }
@@ -14613,7 +14613,7 @@ Ifc4x3_rc1::IfcCompositeProfileDef::IfcCompositeProfileDef(::Ifc4x3_rc1::IfcProf
 
 // Function implementations for IfcCompressor
 boost::optional< ::Ifc4x3_rc1::IfcCompressorTypeEnum::Value > Ifc4x3_rc1::IfcCompressor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCompressorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCompressorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCompressorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCompressor::declaration() const { return *IFC4X3_RC1_IfcCompressor_type; }
@@ -14633,7 +14633,7 @@ Ifc4x3_rc1::IfcCompressorType::IfcCompressorType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCondenser
 boost::optional< ::Ifc4x3_rc1::IfcCondenserTypeEnum::Value > Ifc4x3_rc1::IfcCondenser::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCondenserTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCondenserTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCondenserTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCondenser::declaration() const { return *IFC4X3_RC1_IfcCondenser_type; }
@@ -14693,11 +14693,11 @@ Ifc4x3_rc1::IfcConnectionGeometry::IfcConnectionGeometry() : IfcUtil::IfcBaseEnt
 
 // Function implementations for IfcConnectionPointEccentricity
 boost::optional< double > Ifc4x3_rc1::IfcConnectionPointEccentricity::EccentricityInX() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcConnectionPointEccentricity::EccentricityInY() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcConnectionPointEccentricity::EccentricityInZ() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcConnectionPointEccentricity::declaration() const { return *IFC4X3_RC1_IfcConnectionPointEccentricity_type; }
@@ -14745,17 +14745,17 @@ Ifc4x3_rc1::IfcConnectionVolumeGeometry::IfcConnectionVolumeGeometry(::Ifc4x3_rc
 std::string Ifc4x3_rc1::IfcConstraint::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcConstraint::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcConstraint::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc1::IfcConstraintEnum::Value Ifc4x3_rc1::IfcConstraint::ConstraintGrade() const {  return ::Ifc4x3_rc1::IfcConstraintEnum::FromString(*data_->getArgument(2)); }
 void Ifc4x3_rc1::IfcConstraint::setConstraintGrade(::Ifc4x3_rc1::IfcConstraintEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcConstraintEnum::ToString(v)));data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcConstraint::ConstraintSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc1::IfcActorSelect* Ifc4x3_rc1::IfcConstraint::CreatingActor() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc1::IfcActorSelect>(true); }
 void Ifc4x3_rc1::IfcConstraint::setCreatingActor(::Ifc4x3_rc1::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcConstraint::CreationTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcConstraint::UserDefinedGrade() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc1::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc1::IfcConstraint::HasExternalReferences() const { return data_->getInverse(IFC4X3_RC1_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc1::IfcResourceConstraintRelationship::list::ptr Ifc4x3_rc1::IfcConstraint::PropertiesForConstraint() const { return data_->getInverse(IFC4X3_RC1_IfcResourceConstraintRelationship_type, 2)->as<IfcResourceConstraintRelationship>(); }
@@ -14767,7 +14767,7 @@ Ifc4x3_rc1::IfcConstraint::IfcConstraint(std::string v1_Name, boost::optional< s
 
 // Function implementations for IfcConstructionEquipmentResource
 boost::optional< ::Ifc4x3_rc1::IfcConstructionEquipmentResourceTypeEnum::Value > Ifc4x3_rc1::IfcConstructionEquipmentResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcConstructionEquipmentResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcConstructionEquipmentResource::declaration() const { return *IFC4X3_RC1_IfcConstructionEquipmentResource_type; }
@@ -14787,7 +14787,7 @@ Ifc4x3_rc1::IfcConstructionEquipmentResourceType::IfcConstructionEquipmentResour
 
 // Function implementations for IfcConstructionMaterialResource
 boost::optional< ::Ifc4x3_rc1::IfcConstructionMaterialResourceTypeEnum::Value > Ifc4x3_rc1::IfcConstructionMaterialResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcConstructionMaterialResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcConstructionMaterialResource::declaration() const { return *IFC4X3_RC1_IfcConstructionMaterialResource_type; }
@@ -14807,7 +14807,7 @@ Ifc4x3_rc1::IfcConstructionMaterialResourceType::IfcConstructionMaterialResource
 
 // Function implementations for IfcConstructionProductResource
 boost::optional< ::Ifc4x3_rc1::IfcConstructionProductResourceTypeEnum::Value > Ifc4x3_rc1::IfcConstructionProductResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcConstructionProductResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcConstructionProductResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcConstructionProductResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcConstructionProductResource::declaration() const { return *IFC4X3_RC1_IfcConstructionProductResource_type; }
@@ -14829,7 +14829,7 @@ Ifc4x3_rc1::IfcConstructionProductResourceType::IfcConstructionProductResourceTy
 ::Ifc4x3_rc1::IfcResourceTime* Ifc4x3_rc1::IfcConstructionResource::Usage() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc1::IfcResourceTime>(true); }
 void Ifc4x3_rc1::IfcConstructionResource::setUsage(::Ifc4x3_rc1::IfcResourceTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAppliedValue >::ptr > Ifc4x3_rc1::IfcConstructionResource::BaseCosts() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc1::IfcAppliedValue >(); }
-void Ifc4x3_rc1::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc1::IfcPhysicalQuantity* Ifc4x3_rc1::IfcConstructionResource::BaseQuantity() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc1::IfcPhysicalQuantity>(true); }
 void Ifc4x3_rc1::IfcConstructionResource::setBaseQuantity(::Ifc4x3_rc1::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -14841,7 +14841,7 @@ Ifc4x3_rc1::IfcConstructionResource::IfcConstructionResource(std::string v1_Glob
 
 // Function implementations for IfcConstructionResourceType
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAppliedValue >::ptr > Ifc4x3_rc1::IfcConstructionResourceType::BaseCosts() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc1::IfcAppliedValue >(); }
-void Ifc4x3_rc1::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 ::Ifc4x3_rc1::IfcPhysicalQuantity* Ifc4x3_rc1::IfcConstructionResourceType::BaseQuantity() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc1::IfcPhysicalQuantity>(true); }
 void Ifc4x3_rc1::IfcConstructionResourceType::setBaseQuantity(::Ifc4x3_rc1::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -14853,13 +14853,13 @@ Ifc4x3_rc1::IfcConstructionResourceType::IfcConstructionResourceType(std::string
 
 // Function implementations for IfcContext
 boost::optional< std::string > Ifc4x3_rc1::IfcContext::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcContext::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcContext::Phase() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcRepresentationContext >::ptr > Ifc4x3_rc1::IfcContext::RepresentationContexts() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc1::IfcRepresentationContext >(); }
-void Ifc4x3_rc1::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc1::IfcUnitAssignment* Ifc4x3_rc1::IfcContext::UnitsInContext() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc1::IfcUnitAssignment>(true); }
 void Ifc4x3_rc1::IfcContext::setUnitsInContext(::Ifc4x3_rc1::IfcUnitAssignment* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -14884,7 +14884,7 @@ Ifc4x3_rc1::IfcContextDependentUnit::IfcContextDependentUnit(::Ifc4x3_rc1::IfcDi
 
 // Function implementations for IfcControl
 boost::optional< std::string > Ifc4x3_rc1::IfcControl::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc1::IfcRelAssignsToControl::list::ptr Ifc4x3_rc1::IfcControl::Controls() const { return data_->getInverse(IFC4X3_RC1_IfcRelAssignsToControl_type, 6)->as<IfcRelAssignsToControl>(); }
 
@@ -14895,7 +14895,7 @@ Ifc4x3_rc1::IfcControl::IfcControl(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwn
 
 // Function implementations for IfcController
 boost::optional< ::Ifc4x3_rc1::IfcControllerTypeEnum::Value > Ifc4x3_rc1::IfcController::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcControllerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcController::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcControllerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcController::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcControllerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcController::declaration() const { return *IFC4X3_RC1_IfcController_type; }
@@ -14938,7 +14938,7 @@ Ifc4x3_rc1::IfcConversionBasedUnitWithOffset::IfcConversionBasedUnitWithOffset(:
 
 // Function implementations for IfcConveyorSegment
 boost::optional< ::Ifc4x3_rc1::IfcConveyorSegmentTypeEnum::Value > Ifc4x3_rc1::IfcConveyorSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcConveyorSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcConveyorSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcConveyorSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcConveyorSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcConveyorSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcConveyorSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcConveyorSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcConveyorSegment::declaration() const { return *IFC4X3_RC1_IfcConveyorSegment_type; }
@@ -14958,7 +14958,7 @@ Ifc4x3_rc1::IfcConveyorSegmentType::IfcConveyorSegmentType(std::string v1_Global
 
 // Function implementations for IfcCooledBeam
 boost::optional< ::Ifc4x3_rc1::IfcCooledBeamTypeEnum::Value > Ifc4x3_rc1::IfcCooledBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCooledBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCooledBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCooledBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCooledBeam::declaration() const { return *IFC4X3_RC1_IfcCooledBeam_type; }
@@ -14978,7 +14978,7 @@ Ifc4x3_rc1::IfcCooledBeamType::IfcCooledBeamType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCoolingTower
 boost::optional< ::Ifc4x3_rc1::IfcCoolingTowerTypeEnum::Value > Ifc4x3_rc1::IfcCoolingTower::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCoolingTowerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCoolingTowerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCoolingTowerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCoolingTower::declaration() const { return *IFC4X3_RC1_IfcCoolingTower_type; }
@@ -15012,11 +15012,11 @@ Ifc4x3_rc1::IfcCoordinateOperation::IfcCoordinateOperation(::Ifc4x3_rc1::IfcCoor
 std::string Ifc4x3_rc1::IfcCoordinateReferenceSystem::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcCoordinateReferenceSystem::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcCoordinateReferenceSystem::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcCoordinateReferenceSystem::GeodeticDatum() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcCoordinateReferenceSystem::VerticalDatum() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 ::Ifc4x3_rc1::IfcCoordinateOperation::list::ptr Ifc4x3_rc1::IfcCoordinateReferenceSystem::HasCoordinateOperation() const { return data_->getInverse(IFC4X3_RC1_IfcCoordinateOperation_type, 0)->as<IfcCoordinateOperation>(); }
 
@@ -15027,11 +15027,11 @@ Ifc4x3_rc1::IfcCoordinateReferenceSystem::IfcCoordinateReferenceSystem(std::stri
 
 // Function implementations for IfcCostItem
 boost::optional< ::Ifc4x3_rc1::IfcCostItemTypeEnum::Value > Ifc4x3_rc1::IfcCostItem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCostItemTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc1::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCostItemTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCostItemTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcCostValue >::ptr > Ifc4x3_rc1::IfcCostItem::CostValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc1::IfcCostValue >(); }
-void Ifc4x3_rc1::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPhysicalQuantity >::ptr > Ifc4x3_rc1::IfcCostItem::CostQuantities() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc1::IfcPhysicalQuantity >(); }
-void Ifc4x3_rc1::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCostItem::declaration() const { return *IFC4X3_RC1_IfcCostItem_type; }
@@ -15041,13 +15041,13 @@ Ifc4x3_rc1::IfcCostItem::IfcCostItem(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcCostSchedule
 boost::optional< ::Ifc4x3_rc1::IfcCostScheduleTypeEnum::Value > Ifc4x3_rc1::IfcCostSchedule::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCostScheduleTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc1::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCostScheduleTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCostScheduleTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcCostSchedule::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcCostSchedule::SubmittedOn() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcCostSchedule::UpdateDate() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCostSchedule::declaration() const { return *IFC4X3_RC1_IfcCostSchedule_type; }
@@ -15065,7 +15065,7 @@ Ifc4x3_rc1::IfcCostValue::IfcCostValue(boost::optional< std::string > v1_Name, b
 
 // Function implementations for IfcCourse
 boost::optional< ::Ifc4x3_rc1::IfcCourseTypeEnum::Value > Ifc4x3_rc1::IfcCourse::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCourseTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCourse::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCourseTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCourseTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCourse::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCourseTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCourseTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCourse::declaration() const { return *IFC4X3_RC1_IfcCourse_type; }
@@ -15085,7 +15085,7 @@ Ifc4x3_rc1::IfcCourseType::IfcCourseType(std::string v1_GlobalId, ::Ifc4x3_rc1::
 
 // Function implementations for IfcCovering
 boost::optional< ::Ifc4x3_rc1::IfcCoveringTypeEnum::Value > Ifc4x3_rc1::IfcCovering::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCoveringTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCoveringTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCoveringTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc1::IfcRelCoversSpaces::list::ptr Ifc4x3_rc1::IfcCovering::CoversSpaces() const { return data_->getInverse(IFC4X3_RC1_IfcRelCoversSpaces_type, 5)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x3_rc1::IfcRelCoversBldgElements::list::ptr Ifc4x3_rc1::IfcCovering::CoversElements() const { return data_->getInverse(IFC4X3_RC1_IfcRelCoversBldgElements_type, 5)->as<IfcRelCoversBldgElements>(); }
@@ -15107,7 +15107,7 @@ Ifc4x3_rc1::IfcCoveringType::IfcCoveringType(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcCrewResource
 boost::optional< ::Ifc4x3_rc1::IfcCrewResourceTypeEnum::Value > Ifc4x3_rc1::IfcCrewResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCrewResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCrewResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCrewResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCrewResource::declaration() const { return *IFC4X3_RC1_IfcCrewResource_type; }
@@ -15153,7 +15153,7 @@ void Ifc4x3_rc1::IfcCurrencyRelationship::setRelatedMonetaryUnit(::Ifc4x3_rc1::I
 double Ifc4x3_rc1::IfcCurrencyRelationship::ExchangeRate() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc1::IfcCurrencyRelationship::setExchangeRate(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcCurrencyRelationship::RateDateTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc1::IfcLibraryInformation* Ifc4x3_rc1::IfcCurrencyRelationship::RateSource() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcLibraryInformation>(true); }
 void Ifc4x3_rc1::IfcCurrencyRelationship::setRateSource(::Ifc4x3_rc1::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -15165,7 +15165,7 @@ Ifc4x3_rc1::IfcCurrencyRelationship::IfcCurrencyRelationship(boost::optional< st
 
 // Function implementations for IfcCurtainWall
 boost::optional< ::Ifc4x3_rc1::IfcCurtainWallTypeEnum::Value > Ifc4x3_rc1::IfcCurtainWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCurtainWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCurtainWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCurtainWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCurtainWall::declaration() const { return *IFC4X3_RC1_IfcCurtainWall_type; }
@@ -15241,7 +15241,7 @@ void Ifc4x3_rc1::IfcCurveStyle::setCurveWidth(::Ifc4x3_rc1::IfcSizeSelect* v) {
 ::Ifc4x3_rc1::IfcColour* Ifc4x3_rc1::IfcCurveStyle::CurveColour() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcColour>(true); }
 void Ifc4x3_rc1::IfcCurveStyle::setCurveColour(::Ifc4x3_rc1::IfcColour* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcCurveStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcCurveStyle::declaration() const { return *IFC4X3_RC1_IfcCurveStyle_type; }
@@ -15251,7 +15251,7 @@ Ifc4x3_rc1::IfcCurveStyle::IfcCurveStyle(boost::optional< std::string > v1_Name,
 
 // Function implementations for IfcCurveStyleFont
 boost::optional< std::string > Ifc4x3_rc1::IfcCurveStyleFont::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc4x3_rc1::IfcCurveStyleFontPattern >::ptr Ifc4x3_rc1::IfcCurveStyleFont::PatternList() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc1::IfcCurveStyleFontPattern >(); }
 void Ifc4x3_rc1::IfcCurveStyleFont::setPatternList(aggregate_of< ::Ifc4x3_rc1::IfcCurveStyleFontPattern >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -15263,7 +15263,7 @@ Ifc4x3_rc1::IfcCurveStyleFont::IfcCurveStyleFont(boost::optional< std::string >
 
 // Function implementations for IfcCurveStyleFontAndScaling
 boost::optional< std::string > Ifc4x3_rc1::IfcCurveStyleFontAndScaling::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc1::IfcCurveStyleFontSelect* Ifc4x3_rc1::IfcCurveStyleFontAndScaling::CurveFont() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc1::IfcCurveStyleFontSelect>(true); }
 void Ifc4x3_rc1::IfcCurveStyleFontAndScaling::setCurveFont(::Ifc4x3_rc1::IfcCurveStyleFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 double Ifc4x3_rc1::IfcCurveStyleFontAndScaling::CurveFontScaling() const {  double v = *data_->getArgument(2); return v; }
@@ -15299,7 +15299,7 @@ Ifc4x3_rc1::IfcCylindricalSurface::IfcCylindricalSurface(::Ifc4x3_rc1::IfcAxis2P
 
 // Function implementations for IfcDamper
 boost::optional< ::Ifc4x3_rc1::IfcDamperTypeEnum::Value > Ifc4x3_rc1::IfcDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDamper::declaration() const { return *IFC4X3_RC1_IfcDamper_type; }
@@ -15339,7 +15339,7 @@ void Ifc4x3_rc1::IfcDerivedProfileDef::setParentProfile(::Ifc4x3_rc1::IfcProfile
 ::Ifc4x3_rc1::IfcCartesianTransformationOperator2D* Ifc4x3_rc1::IfcDerivedProfileDef::Operator() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x3_rc1::IfcDerivedProfileDef::setOperator(::Ifc4x3_rc1::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDerivedProfileDef::Label() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDerivedProfileDef::declaration() const { return *IFC4X3_RC1_IfcDerivedProfileDef_type; }
@@ -15353,7 +15353,7 @@ void Ifc4x3_rc1::IfcDerivedUnit::setElements(aggregate_of< ::Ifc4x3_rc1::IfcDeri
 ::Ifc4x3_rc1::IfcDerivedUnitEnum::Value Ifc4x3_rc1::IfcDerivedUnit::UnitType() const {  return ::Ifc4x3_rc1::IfcDerivedUnitEnum::FromString(*data_->getArgument(1)); }
 void Ifc4x3_rc1::IfcDerivedUnit::setUnitType(::Ifc4x3_rc1::IfcDerivedUnitEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcDerivedUnitEnum::ToString(v)));data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDerivedUnit::UserDefinedType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDerivedUnit::declaration() const { return *IFC4X3_RC1_IfcDerivedUnit_type; }
@@ -15409,9 +15409,9 @@ Ifc4x3_rc1::IfcDirection::IfcDirection(std::vector< double > /*[2:3]*/ v1_Direct
 ::Ifc4x3_rc1::IfcCurve* Ifc4x3_rc1::IfcDirectrixCurveSweptAreaSolid::Directrix() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc1::IfcCurve>(true); }
 void Ifc4x3_rc1::IfcDirectrixCurveSweptAreaSolid::setDirectrix(::Ifc4x3_rc1::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDirectrixCurveSweptAreaSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcDirectrixCurveSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcDirectrixCurveSweptAreaSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDirectrixCurveSweptAreaSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcDirectrixCurveSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcDirectrixCurveSweptAreaSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDirectrixCurveSweptAreaSolid::declaration() const { return *IFC4X3_RC1_IfcDirectrixCurveSweptAreaSolid_type; }
@@ -15435,7 +15435,7 @@ Ifc4x3_rc1::IfcDirectrixDistanceSweptAreaSolid::IfcDirectrixDistanceSweptAreaSol
 
 // Function implementations for IfcDiscreteAccessory
 boost::optional< ::Ifc4x3_rc1::IfcDiscreteAccessoryTypeEnum::Value > Ifc4x3_rc1::IfcDiscreteAccessory::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDiscreteAccessoryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDiscreteAccessoryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDiscreteAccessoryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDiscreteAccessory::declaration() const { return *IFC4X3_RC1_IfcDiscreteAccessory_type; }
@@ -15457,13 +15457,13 @@ Ifc4x3_rc1::IfcDiscreteAccessoryType::IfcDiscreteAccessoryType(std::string v1_Gl
 double Ifc4x3_rc1::IfcDistanceExpression::DistanceAlong() const {  double v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcDistanceExpression::setDistanceAlong(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDistanceExpression::OffsetLateral() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDistanceExpression::OffsetVertical() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDistanceExpression::OffsetLongitudinal() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcDistanceExpression::AlongHorizontal() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcDistanceExpression::setAlongHorizontal(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcDistanceExpression::setAlongHorizontal(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDistanceExpression::declaration() const { return *IFC4X3_RC1_IfcDistanceExpression_type; }
@@ -15473,7 +15473,7 @@ Ifc4x3_rc1::IfcDistanceExpression::IfcDistanceExpression(double v1_DistanceAlong
 
 // Function implementations for IfcDistributionBoard
 boost::optional< ::Ifc4x3_rc1::IfcDistributionBoardTypeEnum::Value > Ifc4x3_rc1::IfcDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDistributionBoard::declaration() const { return *IFC4X3_RC1_IfcDistributionBoard_type; }
@@ -15493,7 +15493,7 @@ Ifc4x3_rc1::IfcDistributionBoardType::IfcDistributionBoardType(std::string v1_Gl
 
 // Function implementations for IfcDistributionChamberElement
 boost::optional< ::Ifc4x3_rc1::IfcDistributionChamberElementTypeEnum::Value > Ifc4x3_rc1::IfcDistributionChamberElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDistributionChamberElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDistributionChamberElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDistributionChamberElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDistributionChamberElement::declaration() const { return *IFC4X3_RC1_IfcDistributionChamberElement_type; }
@@ -15572,11 +15572,11 @@ Ifc4x3_rc1::IfcDistributionFlowElementType::IfcDistributionFlowElementType(std::
 
 // Function implementations for IfcDistributionPort
 boost::optional< ::Ifc4x3_rc1::IfcFlowDirectionEnum::Value > Ifc4x3_rc1::IfcDistributionPort::FlowDirection() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcFlowDirectionEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc1::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x3_rc1::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFlowDirectionEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x3_rc1::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFlowDirectionEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcDistributionPortTypeEnum::Value > Ifc4x3_rc1::IfcDistributionPort::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDistributionPortTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDistributionPortTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDistributionPortTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcDistributionSystemEnum::Value > Ifc4x3_rc1::IfcDistributionPort::SystemType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDistributionSystemEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc1::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x3_rc1::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x3_rc1::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDistributionPort::declaration() const { return *IFC4X3_RC1_IfcDistributionPort_type; }
@@ -15586,9 +15586,9 @@ Ifc4x3_rc1::IfcDistributionPort::IfcDistributionPort(std::string v1_GlobalId, ::
 
 // Function implementations for IfcDistributionSystem
 boost::optional< std::string > Ifc4x3_rc1::IfcDistributionSystem::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcDistributionSystemEnum::Value > Ifc4x3_rc1::IfcDistributionSystem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDistributionSystemEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc1::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDistributionSystem::declaration() const { return *IFC4X3_RC1_IfcDistributionSystem_type; }
@@ -15602,35 +15602,35 @@ void Ifc4x3_rc1::IfcDocumentInformation::setIdentification(std::string v) { {Ifc
 std::string Ifc4x3_rc1::IfcDocumentInformation::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcDocumentInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::Location() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::Purpose() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::IntendedUse() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::Scope() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::Revision() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc1::IfcActorSelect* Ifc4x3_rc1::IfcDocumentInformation::DocumentOwner() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc1::IfcActorSelect>(true); }
 void Ifc4x3_rc1::IfcDocumentInformation::setDocumentOwner(::Ifc4x3_rc1::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc1::IfcDocumentInformation::Editors() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::CreationTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::LastRevisionTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::ElectronicFormat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::ValidFrom() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformation::ValidUntil() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc1::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcDocumentConfidentialityEnum::Value > Ifc4x3_rc1::IfcDocumentInformation::Confidentiality() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDocumentConfidentialityEnum::FromString(*data_->getArgument(15)); }
-void Ifc4x3_rc1::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x3_rc1::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDocumentConfidentialityEnum::ToString(*v)));data_->setArgument(15,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x3_rc1::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDocumentConfidentialityEnum::ToString(*v)));}data_->setArgument(15,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcDocumentStatusEnum::Value > Ifc4x3_rc1::IfcDocumentInformation::Status() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDocumentStatusEnum::FromString(*data_->getArgument(16)); }
-void Ifc4x3_rc1::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x3_rc1::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDocumentStatusEnum::ToString(*v)));data_->setArgument(16,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x3_rc1::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDocumentStatusEnum::ToString(*v)));}data_->setArgument(16,attr);} }
 
 ::Ifc4x3_rc1::IfcRelAssociatesDocument::list::ptr Ifc4x3_rc1::IfcDocumentInformation::DocumentInfoForObjects() const { return data_->getInverse(IFC4X3_RC1_IfcRelAssociatesDocument_type, 5)->as<IfcRelAssociatesDocument>(); }
 ::Ifc4x3_rc1::IfcDocumentReference::list::ptr Ifc4x3_rc1::IfcDocumentInformation::HasDocumentReferences() const { return data_->getInverse(IFC4X3_RC1_IfcDocumentReference_type, 4)->as<IfcDocumentReference>(); }
@@ -15648,7 +15648,7 @@ void Ifc4x3_rc1::IfcDocumentInformationRelationship::setRelatingDocument(::Ifc4x
 aggregate_of< ::Ifc4x3_rc1::IfcDocumentInformation >::ptr Ifc4x3_rc1::IfcDocumentInformationRelationship::RelatedDocuments() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc1::IfcDocumentInformation >(); }
 void Ifc4x3_rc1::IfcDocumentInformationRelationship::setRelatedDocuments(aggregate_of< ::Ifc4x3_rc1::IfcDocumentInformation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentInformationRelationship::RelationshipType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDocumentInformationRelationship::declaration() const { return *IFC4X3_RC1_IfcDocumentInformationRelationship_type; }
@@ -15658,7 +15658,7 @@ Ifc4x3_rc1::IfcDocumentInformationRelationship::IfcDocumentInformationRelationsh
 
 // Function implementations for IfcDocumentReference
 boost::optional< std::string > Ifc4x3_rc1::IfcDocumentReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc1::IfcDocumentInformation* Ifc4x3_rc1::IfcDocumentReference::ReferencedDocument() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc1::IfcDocumentInformation>(true); }
 void Ifc4x3_rc1::IfcDocumentReference::setReferencedDocument(::Ifc4x3_rc1::IfcDocumentInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -15671,15 +15671,15 @@ Ifc4x3_rc1::IfcDocumentReference::IfcDocumentReference(boost::optional< std::str
 
 // Function implementations for IfcDoor
 boost::optional< double > Ifc4x3_rc1::IfcDoor::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoor::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcDoorTypeEnum::Value > Ifc4x3_rc1::IfcDoor::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDoorTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDoorTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDoorTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcDoorTypeOperationEnum::Value > Ifc4x3_rc1::IfcDoor::OperationType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc1::IfcDoor::setOperationType(boost::optional< ::Ifc4x3_rc1::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDoorTypeOperationEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcDoor::setOperationType(boost::optional< ::Ifc4x3_rc1::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDoorTypeOperationEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDoor::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDoor::declaration() const { return *IFC4X3_RC1_IfcDoor_type; }
@@ -15689,31 +15689,31 @@ Ifc4x3_rc1::IfcDoor::IfcDoor(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHist
 
 // Function implementations for IfcDoorLiningProperties
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::ThresholdDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::ThresholdThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::TransomThickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::TransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::LiningOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::ThresholdOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::CasingThickness() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::CasingDepth() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 ::Ifc4x3_rc1::IfcShapeAspect* Ifc4x3_rc1::IfcDoorLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(14)))->as<::Ifc4x3_rc1::IfcShapeAspect>(true); }
 void Ifc4x3_rc1::IfcDoorLiningProperties::setShapeAspectStyle(::Ifc4x3_rc1::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc1::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc1::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDoorLiningProperties::declaration() const { return *IFC4X3_RC1_IfcDoorLiningProperties_type; }
@@ -15723,11 +15723,11 @@ Ifc4x3_rc1::IfcDoorLiningProperties::IfcDoorLiningProperties(std::string v1_Glob
 
 // Function implementations for IfcDoorPanelProperties
 boost::optional< double > Ifc4x3_rc1::IfcDoorPanelProperties::PanelDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc1::IfcDoorPanelOperationEnum::Value Ifc4x3_rc1::IfcDoorPanelProperties::PanelOperation() const {  return ::Ifc4x3_rc1::IfcDoorPanelOperationEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc1::IfcDoorPanelProperties::setPanelOperation(::Ifc4x3_rc1::IfcDoorPanelOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcDoorPanelOperationEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcDoorPanelProperties::PanelWidth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc1::IfcDoorPanelPositionEnum::Value Ifc4x3_rc1::IfcDoorPanelProperties::PanelPosition() const {  return ::Ifc4x3_rc1::IfcDoorPanelPositionEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc1::IfcDoorPanelProperties::setPanelPosition(::Ifc4x3_rc1::IfcDoorPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcDoorPanelPositionEnum::ToString(v)));data_->setArgument(7,attr);} }
 ::Ifc4x3_rc1::IfcShapeAspect* Ifc4x3_rc1::IfcDoorPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc1::IfcShapeAspect>(true); }
@@ -15769,9 +15769,9 @@ void Ifc4x3_rc1::IfcDoorType::setPredefinedType(::Ifc4x3_rc1::IfcDoorTypeEnum::V
 ::Ifc4x3_rc1::IfcDoorTypeOperationEnum::Value Ifc4x3_rc1::IfcDoorType::OperationType() const {  return ::Ifc4x3_rc1::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc1::IfcDoorType::setOperationType(::Ifc4x3_rc1::IfcDoorTypeOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcDoorTypeOperationEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcDoorType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcDoorType::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDoorType::declaration() const { return *IFC4X3_RC1_IfcDoorType_type; }
@@ -15797,7 +15797,7 @@ Ifc4x3_rc1::IfcDraughtingPreDefinedCurveFont::IfcDraughtingPreDefinedCurveFont(s
 
 // Function implementations for IfcDuctFitting
 boost::optional< ::Ifc4x3_rc1::IfcDuctFittingTypeEnum::Value > Ifc4x3_rc1::IfcDuctFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDuctFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDuctFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDuctFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDuctFitting::declaration() const { return *IFC4X3_RC1_IfcDuctFitting_type; }
@@ -15817,7 +15817,7 @@ Ifc4x3_rc1::IfcDuctFittingType::IfcDuctFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcDuctSegment
 boost::optional< ::Ifc4x3_rc1::IfcDuctSegmentTypeEnum::Value > Ifc4x3_rc1::IfcDuctSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDuctSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDuctSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDuctSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDuctSegment::declaration() const { return *IFC4X3_RC1_IfcDuctSegment_type; }
@@ -15837,7 +15837,7 @@ Ifc4x3_rc1::IfcDuctSegmentType::IfcDuctSegmentType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcDuctSilencer
 boost::optional< ::Ifc4x3_rc1::IfcDuctSilencerTypeEnum::Value > Ifc4x3_rc1::IfcDuctSilencer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDuctSilencerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDuctSilencerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDuctSilencerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcDuctSilencer::declaration() const { return *IFC4X3_RC1_IfcDuctSilencer_type; }
@@ -15857,7 +15857,7 @@ Ifc4x3_rc1::IfcDuctSilencerType::IfcDuctSilencerType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcEarthworksCut
 boost::optional< ::Ifc4x3_rc1::IfcEarthworksCutTypeEnum::Value > Ifc4x3_rc1::IfcEarthworksCut::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcEarthworksCutTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcEarthworksCut::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEarthworksCutTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEarthworksCutTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcEarthworksCut::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEarthworksCutTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEarthworksCutTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcEarthworksCut::declaration() const { return *IFC4X3_RC1_IfcEarthworksCut_type; }
@@ -15875,7 +15875,7 @@ Ifc4x3_rc1::IfcEarthworksElement::IfcEarthworksElement(std::string v1_GlobalId,
 
 // Function implementations for IfcEarthworksFill
 boost::optional< ::Ifc4x3_rc1::IfcEarthworksFillTypeEnum::Value > Ifc4x3_rc1::IfcEarthworksFill::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcEarthworksFillTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcEarthworksFill::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEarthworksFillTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEarthworksFillTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcEarthworksFill::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEarthworksFillTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEarthworksFillTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcEarthworksFill::declaration() const { return *IFC4X3_RC1_IfcEarthworksFill_type; }
@@ -15919,7 +15919,7 @@ Ifc4x3_rc1::IfcEdgeLoop::IfcEdgeLoop(aggregate_of< ::Ifc4x3_rc1::IfcOrientedEdge
 
 // Function implementations for IfcElectricAppliance
 boost::optional< ::Ifc4x3_rc1::IfcElectricApplianceTypeEnum::Value > Ifc4x3_rc1::IfcElectricAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcElectricApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcElectricAppliance::declaration() const { return *IFC4X3_RC1_IfcElectricAppliance_type; }
@@ -15939,7 +15939,7 @@ Ifc4x3_rc1::IfcElectricApplianceType::IfcElectricApplianceType(std::string v1_Gl
 
 // Function implementations for IfcElectricDistributionBoard
 boost::optional< ::Ifc4x3_rc1::IfcElectricDistributionBoardTypeEnum::Value > Ifc4x3_rc1::IfcElectricDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcElectricDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcElectricDistributionBoard::declaration() const { return *IFC4X3_RC1_IfcElectricDistributionBoard_type; }
@@ -15959,7 +15959,7 @@ Ifc4x3_rc1::IfcElectricDistributionBoardType::IfcElectricDistributionBoardType(s
 
 // Function implementations for IfcElectricFlowStorageDevice
 boost::optional< ::Ifc4x3_rc1::IfcElectricFlowStorageDeviceTypeEnum::Value > Ifc4x3_rc1::IfcElectricFlowStorageDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcElectricFlowStorageDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcElectricFlowStorageDevice::declaration() const { return *IFC4X3_RC1_IfcElectricFlowStorageDevice_type; }
@@ -15979,7 +15979,7 @@ Ifc4x3_rc1::IfcElectricFlowStorageDeviceType::IfcElectricFlowStorageDeviceType(s
 
 // Function implementations for IfcElectricFlowTreatmentDevice
 boost::optional< ::Ifc4x3_rc1::IfcElectricFlowTreatmentDeviceTypeEnum::Value > Ifc4x3_rc1::IfcElectricFlowTreatmentDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcElectricFlowTreatmentDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcElectricFlowTreatmentDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricFlowTreatmentDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricFlowTreatmentDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcElectricFlowTreatmentDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricFlowTreatmentDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricFlowTreatmentDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcElectricFlowTreatmentDevice::declaration() const { return *IFC4X3_RC1_IfcElectricFlowTreatmentDevice_type; }
@@ -15999,7 +15999,7 @@ Ifc4x3_rc1::IfcElectricFlowTreatmentDeviceType::IfcElectricFlowTreatmentDeviceTy
 
 // Function implementations for IfcElectricGenerator
 boost::optional< ::Ifc4x3_rc1::IfcElectricGeneratorTypeEnum::Value > Ifc4x3_rc1::IfcElectricGenerator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcElectricGeneratorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricGeneratorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricGeneratorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcElectricGenerator::declaration() const { return *IFC4X3_RC1_IfcElectricGenerator_type; }
@@ -16019,7 +16019,7 @@ Ifc4x3_rc1::IfcElectricGeneratorType::IfcElectricGeneratorType(std::string v1_Gl
 
 // Function implementations for IfcElectricMotor
 boost::optional< ::Ifc4x3_rc1::IfcElectricMotorTypeEnum::Value > Ifc4x3_rc1::IfcElectricMotor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcElectricMotorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricMotorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricMotorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcElectricMotor::declaration() const { return *IFC4X3_RC1_IfcElectricMotor_type; }
@@ -16039,7 +16039,7 @@ Ifc4x3_rc1::IfcElectricMotorType::IfcElectricMotorType(std::string v1_GlobalId,
 
 // Function implementations for IfcElectricTimeControl
 boost::optional< ::Ifc4x3_rc1::IfcElectricTimeControlTypeEnum::Value > Ifc4x3_rc1::IfcElectricTimeControl::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcElectricTimeControlTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricTimeControlTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElectricTimeControlTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcElectricTimeControl::declaration() const { return *IFC4X3_RC1_IfcElectricTimeControl_type; }
@@ -16059,7 +16059,7 @@ Ifc4x3_rc1::IfcElectricTimeControlType::IfcElectricTimeControlType(std::string v
 
 // Function implementations for IfcElement
 boost::optional< std::string > Ifc4x3_rc1::IfcElement::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc1::IfcRelFillsElement::list::ptr Ifc4x3_rc1::IfcElement::FillsVoids() const { return data_->getInverse(IFC4X3_RC1_IfcRelFillsElement_type, 5)->as<IfcRelFillsElement>(); }
 ::Ifc4x3_rc1::IfcRelConnectsElements::list::ptr Ifc4x3_rc1::IfcElement::ConnectedTo() const { return data_->getInverse(IFC4X3_RC1_IfcRelConnectsElements_type, 5)->as<IfcRelConnectsElements>(); }
@@ -16080,9 +16080,9 @@ Ifc4x3_rc1::IfcElement::IfcElement(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwn
 
 // Function implementations for IfcElementAssembly
 boost::optional< ::Ifc4x3_rc1::IfcAssemblyPlaceEnum::Value > Ifc4x3_rc1::IfcElementAssembly::AssemblyPlace() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x3_rc1::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAssemblyPlaceEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x3_rc1::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcAssemblyPlaceEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcElementAssemblyTypeEnum::Value > Ifc4x3_rc1::IfcElementAssembly::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcElementAssemblyTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc1::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElementAssemblyTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElementAssemblyTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcElementAssembly::declaration() const { return *IFC4X3_RC1_IfcElementAssembly_type; }
@@ -16118,7 +16118,7 @@ Ifc4x3_rc1::IfcElementComponentType::IfcElementComponentType(std::string v1_Glob
 
 // Function implementations for IfcElementQuantity
 boost::optional< std::string > Ifc4x3_rc1::IfcElementQuantity::MethodOfMeasurement() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x3_rc1::IfcPhysicalQuantity >::ptr Ifc4x3_rc1::IfcElementQuantity::Quantities() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc1::IfcPhysicalQuantity >(); }
 void Ifc4x3_rc1::IfcElementQuantity::setQuantities(aggregate_of< ::Ifc4x3_rc1::IfcPhysicalQuantity >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -16130,7 +16130,7 @@ Ifc4x3_rc1::IfcElementQuantity::IfcElementQuantity(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcElementType
 boost::optional< std::string > Ifc4x3_rc1::IfcElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcElementType::declaration() const { return *IFC4X3_RC1_IfcElementType_type; }
@@ -16190,7 +16190,7 @@ Ifc4x3_rc1::IfcEnergyConversionDeviceType::IfcEnergyConversionDeviceType(std::st
 
 // Function implementations for IfcEngine
 boost::optional< ::Ifc4x3_rc1::IfcEngineTypeEnum::Value > Ifc4x3_rc1::IfcEngine::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcEngineTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEngineTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEngineTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcEngine::declaration() const { return *IFC4X3_RC1_IfcEngine_type; }
@@ -16210,7 +16210,7 @@ Ifc4x3_rc1::IfcEngineType::IfcEngineType(std::string v1_GlobalId, ::Ifc4x3_rc1::
 
 // Function implementations for IfcEvaporativeCooler
 boost::optional< ::Ifc4x3_rc1::IfcEvaporativeCoolerTypeEnum::Value > Ifc4x3_rc1::IfcEvaporativeCooler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcEvaporativeCoolerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEvaporativeCoolerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEvaporativeCoolerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcEvaporativeCooler::declaration() const { return *IFC4X3_RC1_IfcEvaporativeCooler_type; }
@@ -16230,7 +16230,7 @@ Ifc4x3_rc1::IfcEvaporativeCoolerType::IfcEvaporativeCoolerType(std::string v1_Gl
 
 // Function implementations for IfcEvaporator
 boost::optional< ::Ifc4x3_rc1::IfcEvaporatorTypeEnum::Value > Ifc4x3_rc1::IfcEvaporator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcEvaporatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEvaporatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEvaporatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcEvaporator::declaration() const { return *IFC4X3_RC1_IfcEvaporator_type; }
@@ -16250,11 +16250,11 @@ Ifc4x3_rc1::IfcEvaporatorType::IfcEvaporatorType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcEvent
 boost::optional< ::Ifc4x3_rc1::IfcEventTypeEnum::Value > Ifc4x3_rc1::IfcEvent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcEventTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc1::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEventTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEventTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcEventTriggerTypeEnum::Value > Ifc4x3_rc1::IfcEvent::EventTriggerType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x3_rc1::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEventTriggerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x3_rc1::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcEventTriggerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcEvent::UserDefinedEventTriggerType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 ::Ifc4x3_rc1::IfcEventTime* Ifc4x3_rc1::IfcEvent::EventOccurenceTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc1::IfcEventTime>(true); }
 void Ifc4x3_rc1::IfcEvent::setEventOccurenceTime(::Ifc4x3_rc1::IfcEventTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -16266,13 +16266,13 @@ Ifc4x3_rc1::IfcEvent::IfcEvent(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHi
 
 // Function implementations for IfcEventTime
 boost::optional< std::string > Ifc4x3_rc1::IfcEventTime::ActualDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcEventTime::EarlyDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcEventTime::LateDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcEventTime::ScheduleDate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcEventTime::declaration() const { return *IFC4X3_RC1_IfcEventTime_type; }
@@ -16286,7 +16286,7 @@ void Ifc4x3_rc1::IfcEventType::setPredefinedType(::Ifc4x3_rc1::IfcEventTypeEnum:
 ::Ifc4x3_rc1::IfcEventTriggerTypeEnum::Value Ifc4x3_rc1::IfcEventType::EventTriggerType() const {  return ::Ifc4x3_rc1::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc1::IfcEventType::setEventTriggerType(::Ifc4x3_rc1::IfcEventTriggerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcEventTriggerTypeEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcEventType::UserDefinedEventTriggerType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcEventType::declaration() const { return *IFC4X3_RC1_IfcEventType_type; }
@@ -16296,9 +16296,9 @@ Ifc4x3_rc1::IfcEventType::IfcEventType(std::string v1_GlobalId, ::Ifc4x3_rc1::If
 
 // Function implementations for IfcExtendedProperties
 boost::optional< std::string > Ifc4x3_rc1::IfcExtendedProperties::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcExtendedProperties::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc1::IfcProperty >::ptr Ifc4x3_rc1::IfcExtendedProperties::Properties() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc1::IfcProperty >(); }
 void Ifc4x3_rc1::IfcExtendedProperties::setProperties(aggregate_of< ::Ifc4x3_rc1::IfcProperty >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -16318,11 +16318,11 @@ Ifc4x3_rc1::IfcExternalInformation::IfcExternalInformation() : IfcUtil::IfcBaseE
 
 // Function implementations for IfcExternalReference
 boost::optional< std::string > Ifc4x3_rc1::IfcExternalReference::Location() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcExternalReference::Identification() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcExternalReference::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc1::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc1::IfcExternalReference::ExternalReferenceForResources() const { return data_->getInverse(IFC4X3_RC1_IfcExternalReferenceRelationship_type, 2)->as<IfcExternalReferenceRelationship>(); }
 
@@ -16345,7 +16345,7 @@ Ifc4x3_rc1::IfcExternalReferenceRelationship::IfcExternalReferenceRelationship(b
 
 // Function implementations for IfcExternalSpatialElement
 boost::optional< ::Ifc4x3_rc1::IfcExternalSpatialElementTypeEnum::Value > Ifc4x3_rc1::IfcExternalSpatialElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcExternalSpatialElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcExternalSpatialElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcExternalSpatialElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc1::IfcRelSpaceBoundary::list::ptr Ifc4x3_rc1::IfcExternalSpatialElement::BoundedBy() const { return data_->getInverse(IFC4X3_RC1_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
 
@@ -16501,17 +16501,17 @@ Ifc4x3_rc1::IfcFacilityPart::IfcFacilityPart(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcFailureConnectionCondition
 boost::optional< double > Ifc4x3_rc1::IfcFailureConnectionCondition::TensionFailureX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcFailureConnectionCondition::TensionFailureY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcFailureConnectionCondition::TensionFailureZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcFailureConnectionCondition::CompressionFailureX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcFailureConnectionCondition::CompressionFailureY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcFailureConnectionCondition::CompressionFailureZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFailureConnectionCondition::declaration() const { return *IFC4X3_RC1_IfcFailureConnectionCondition_type; }
@@ -16521,7 +16521,7 @@ Ifc4x3_rc1::IfcFailureConnectionCondition::IfcFailureConnectionCondition(boost::
 
 // Function implementations for IfcFan
 boost::optional< ::Ifc4x3_rc1::IfcFanTypeEnum::Value > Ifc4x3_rc1::IfcFan::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcFanTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcFan::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFanTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcFan::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFanTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFan::declaration() const { return *IFC4X3_RC1_IfcFan_type; }
@@ -16541,7 +16541,7 @@ Ifc4x3_rc1::IfcFanType::IfcFanType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwn
 
 // Function implementations for IfcFastener
 boost::optional< ::Ifc4x3_rc1::IfcFastenerTypeEnum::Value > Ifc4x3_rc1::IfcFastener::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcFastenerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFastenerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFastenerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFastener::declaration() const { return *IFC4X3_RC1_IfcFastener_type; }
@@ -16589,7 +16589,7 @@ Ifc4x3_rc1::IfcFeatureElementSubtraction::IfcFeatureElementSubtraction(std::stri
 aggregate_of_instance::ptr Ifc4x3_rc1::IfcFillAreaStyle::FillStyles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcFillAreaStyle::setFillStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcFillAreaStyle::ModelorDraughting() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcFillAreaStyle::setModelorDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcFillAreaStyle::setModelorDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFillAreaStyle::declaration() const { return *IFC4X3_RC1_IfcFillAreaStyle_type; }
@@ -16631,7 +16631,7 @@ Ifc4x3_rc1::IfcFillAreaStyleTiles::IfcFillAreaStyleTiles(aggregate_of< ::Ifc4x3_
 
 // Function implementations for IfcFilter
 boost::optional< ::Ifc4x3_rc1::IfcFilterTypeEnum::Value > Ifc4x3_rc1::IfcFilter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcFilterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFilterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFilterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFilter::declaration() const { return *IFC4X3_RC1_IfcFilter_type; }
@@ -16651,7 +16651,7 @@ Ifc4x3_rc1::IfcFilterType::IfcFilterType(std::string v1_GlobalId, ::Ifc4x3_rc1::
 
 // Function implementations for IfcFireSuppressionTerminal
 boost::optional< ::Ifc4x3_rc1::IfcFireSuppressionTerminalTypeEnum::Value > Ifc4x3_rc1::IfcFireSuppressionTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcFireSuppressionTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFireSuppressionTerminal::declaration() const { return *IFC4X3_RC1_IfcFireSuppressionTerminal_type; }
@@ -16713,7 +16713,7 @@ Ifc4x3_rc1::IfcFlowFittingType::IfcFlowFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcFlowInstrument
 boost::optional< ::Ifc4x3_rc1::IfcFlowInstrumentTypeEnum::Value > Ifc4x3_rc1::IfcFlowInstrument::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcFlowInstrumentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFlowInstrumentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFlowInstrumentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFlowInstrument::declaration() const { return *IFC4X3_RC1_IfcFlowInstrument_type; }
@@ -16733,7 +16733,7 @@ Ifc4x3_rc1::IfcFlowInstrumentType::IfcFlowInstrumentType(std::string v1_GlobalId
 
 // Function implementations for IfcFlowMeter
 boost::optional< ::Ifc4x3_rc1::IfcFlowMeterTypeEnum::Value > Ifc4x3_rc1::IfcFlowMeter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcFlowMeterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFlowMeterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFlowMeterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFlowMeter::declaration() const { return *IFC4X3_RC1_IfcFlowMeter_type; }
@@ -16833,7 +16833,7 @@ Ifc4x3_rc1::IfcFlowTreatmentDeviceType::IfcFlowTreatmentDeviceType(std::string v
 
 // Function implementations for IfcFooting
 boost::optional< ::Ifc4x3_rc1::IfcFootingTypeEnum::Value > Ifc4x3_rc1::IfcFooting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcFootingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFootingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFootingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFooting::declaration() const { return *IFC4X3_RC1_IfcFooting_type; }
@@ -16869,7 +16869,7 @@ Ifc4x3_rc1::IfcFurnishingElementType::IfcFurnishingElementType(std::string v1_Gl
 
 // Function implementations for IfcFurniture
 boost::optional< ::Ifc4x3_rc1::IfcFurnitureTypeEnum::Value > Ifc4x3_rc1::IfcFurniture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcFurnitureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFurniture::declaration() const { return *IFC4X3_RC1_IfcFurniture_type; }
@@ -16881,7 +16881,7 @@ Ifc4x3_rc1::IfcFurniture::IfcFurniture(std::string v1_GlobalId, ::Ifc4x3_rc1::If
 ::Ifc4x3_rc1::IfcAssemblyPlaceEnum::Value Ifc4x3_rc1::IfcFurnitureType::AssemblyPlace() const {  return ::Ifc4x3_rc1::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc1::IfcFurnitureType::setAssemblyPlace(::Ifc4x3_rc1::IfcAssemblyPlaceEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcAssemblyPlaceEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcFurnitureTypeEnum::Value > Ifc4x3_rc1::IfcFurnitureType::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcFurnitureTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcFurnitureType::declaration() const { return *IFC4X3_RC1_IfcFurnitureType_type; }
@@ -16891,7 +16891,7 @@ Ifc4x3_rc1::IfcFurnitureType::IfcFurnitureType(std::string v1_GlobalId, ::Ifc4x3
 
 // Function implementations for IfcGeographicElement
 boost::optional< ::Ifc4x3_rc1::IfcGeographicElementTypeEnum::Value > Ifc4x3_rc1::IfcGeographicElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcGeographicElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcGeographicElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcGeographicElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcGeographicElement::declaration() const { return *IFC4X3_RC1_IfcGeographicElement_type; }
@@ -16921,7 +16921,7 @@ Ifc4x3_rc1::IfcGeometricCurveSet::IfcGeometricCurveSet(aggregate_of_instance::pt
 int Ifc4x3_rc1::IfcGeometricRepresentationContext::CoordinateSpaceDimension() const {  int v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc1::IfcGeometricRepresentationContext::setCoordinateSpaceDimension(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcGeometricRepresentationContext::Precision() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc1::IfcAxis2Placement* Ifc4x3_rc1::IfcGeometricRepresentationContext::WorldCoordinateSystem() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc1::IfcAxis2Placement>(true); }
 void Ifc4x3_rc1::IfcGeometricRepresentationContext::setWorldCoordinateSystem(::Ifc4x3_rc1::IfcAxis2Placement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 ::Ifc4x3_rc1::IfcDirection* Ifc4x3_rc1::IfcGeometricRepresentationContext::TrueNorth() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc1::IfcDirection>(true); }
@@ -16947,11 +16947,11 @@ Ifc4x3_rc1::IfcGeometricRepresentationItem::IfcGeometricRepresentationItem() : I
 ::Ifc4x3_rc1::IfcGeometricRepresentationContext* Ifc4x3_rc1::IfcGeometricRepresentationSubContext::ParentContext() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcGeometricRepresentationContext>(true); }
 void Ifc4x3_rc1::IfcGeometricRepresentationSubContext::setParentContext(::Ifc4x3_rc1::IfcGeometricRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcGeometricRepresentationSubContext::TargetScale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc1::IfcGeometricProjectionEnum::Value Ifc4x3_rc1::IfcGeometricRepresentationSubContext::TargetView() const {  return ::Ifc4x3_rc1::IfcGeometricProjectionEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc1::IfcGeometricRepresentationSubContext::setTargetView(::Ifc4x3_rc1::IfcGeometricProjectionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcGeometricProjectionEnum::ToString(v)));data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcGeometricRepresentationSubContext::UserDefinedTargetView() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcGeometricRepresentationSubContext::declaration() const { return *IFC4X3_RC1_IfcGeometricRepresentationSubContext_type; }
@@ -17015,9 +17015,9 @@ void Ifc4x3_rc1::IfcGrid::setUAxes(aggregate_of< ::Ifc4x3_rc1::IfcGridAxis >::pt
 aggregate_of< ::Ifc4x3_rc1::IfcGridAxis >::ptr Ifc4x3_rc1::IfcGrid::VAxes() const {  aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc1::IfcGridAxis >(); }
 void Ifc4x3_rc1::IfcGrid::setVAxes(aggregate_of< ::Ifc4x3_rc1::IfcGridAxis >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcGridAxis >::ptr > Ifc4x3_rc1::IfcGrid::WAxes() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc1::IfcGridAxis >(); }
-void Ifc4x3_rc1::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcGridTypeEnum::Value > Ifc4x3_rc1::IfcGrid::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcGridTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcGridTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcGridTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcGrid::declaration() const { return *IFC4X3_RC1_IfcGrid_type; }
@@ -17027,7 +17027,7 @@ Ifc4x3_rc1::IfcGrid::IfcGrid(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHist
 
 // Function implementations for IfcGridAxis
 boost::optional< std::string > Ifc4x3_rc1::IfcGridAxis::AxisTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc1::IfcCurve* Ifc4x3_rc1::IfcGridAxis::AxisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc1::IfcCurve>(true); }
 void Ifc4x3_rc1::IfcGridAxis::setAxisCurve(::Ifc4x3_rc1::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 bool Ifc4x3_rc1::IfcGridAxis::SameSense() const {  bool v = *data_->getArgument(2); return v; }
@@ -17078,7 +17078,7 @@ Ifc4x3_rc1::IfcHalfSpaceSolid::IfcHalfSpaceSolid(::Ifc4x3_rc1::IfcSurface* v1_Ba
 
 // Function implementations for IfcHeatExchanger
 boost::optional< ::Ifc4x3_rc1::IfcHeatExchangerTypeEnum::Value > Ifc4x3_rc1::IfcHeatExchanger::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcHeatExchangerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcHeatExchangerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcHeatExchangerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcHeatExchanger::declaration() const { return *IFC4X3_RC1_IfcHeatExchanger_type; }
@@ -17098,7 +17098,7 @@ Ifc4x3_rc1::IfcHeatExchangerType::IfcHeatExchangerType(std::string v1_GlobalId,
 
 // Function implementations for IfcHumidifier
 boost::optional< ::Ifc4x3_rc1::IfcHumidifierTypeEnum::Value > Ifc4x3_rc1::IfcHumidifier::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcHumidifierTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcHumidifierTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcHumidifierTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcHumidifier::declaration() const { return *IFC4X3_RC1_IfcHumidifier_type; }
@@ -17126,11 +17126,11 @@ void Ifc4x3_rc1::IfcIShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc1::IfcIShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc1::IfcIShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcIShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcIShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcIShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcIShapeProfileDef::declaration() const { return *IFC4X3_RC1_IfcIShapeProfileDef_type; }
@@ -17170,7 +17170,7 @@ Ifc4x3_rc1::IfcImpactProtectionDeviceType::IfcImpactProtectionDeviceType(std::st
 
 // Function implementations for IfcInclinedReferenceSweptAreaSolid
 boost::optional< bool > Ifc4x3_rc1::IfcInclinedReferenceSweptAreaSolid::FixedAxisVertical() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } bool v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcInclinedReferenceSweptAreaSolid::setFixedAxisVertical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcInclinedReferenceSweptAreaSolid::setFixedAxisVertical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc1::IfcAxisLateralInclination* Ifc4x3_rc1::IfcInclinedReferenceSweptAreaSolid::Inclinating() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcAxisLateralInclination>(true); }
 void Ifc4x3_rc1::IfcInclinedReferenceSweptAreaSolid::setInclinating(::Ifc4x3_rc1::IfcAxisLateralInclination* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -17184,7 +17184,7 @@ Ifc4x3_rc1::IfcInclinedReferenceSweptAreaSolid::IfcInclinedReferenceSweptAreaSol
 ::Ifc4x3_rc1::IfcTessellatedFaceSet* Ifc4x3_rc1::IfcIndexedColourMap::MappedTo() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc1::IfcTessellatedFaceSet>(true); }
 void Ifc4x3_rc1::IfcIndexedColourMap::setMappedTo(::Ifc4x3_rc1::IfcTessellatedFaceSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcIndexedColourMap::Opacity() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc1::IfcColourRgbList* Ifc4x3_rc1::IfcIndexedColourMap::Colours() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc1::IfcColourRgbList>(true); }
 void Ifc4x3_rc1::IfcIndexedColourMap::setColours(::Ifc4x3_rc1::IfcColourRgbList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::vector< int > /*[1:?]*/ Ifc4x3_rc1::IfcIndexedColourMap::ColourIndex() const {  std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
@@ -17200,9 +17200,9 @@ Ifc4x3_rc1::IfcIndexedColourMap::IfcIndexedColourMap(::Ifc4x3_rc1::IfcTessellate
 ::Ifc4x3_rc1::IfcCartesianPointList* Ifc4x3_rc1::IfcIndexedPolyCurve::Points() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc1::IfcCartesianPointList>(true); }
 void Ifc4x3_rc1::IfcIndexedPolyCurve::setPoints(::Ifc4x3_rc1::IfcCartesianPointList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc1::IfcIndexedPolyCurve::Segments() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcIndexedPolyCurve::SelfIntersect() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcIndexedPolyCurve::declaration() const { return *IFC4X3_RC1_IfcIndexedPolyCurve_type; }
@@ -17245,7 +17245,7 @@ Ifc4x3_rc1::IfcIndexedTextureMap::IfcIndexedTextureMap(aggregate_of< ::Ifc4x3_rc
 
 // Function implementations for IfcIndexedTriangleTextureMap
 boost::optional< std::vector< std::vector< int > > > Ifc4x3_rc1::IfcIndexedTriangleTextureMap::TexCoordIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcIndexedTriangleTextureMap::declaration() const { return *IFC4X3_RC1_IfcIndexedTriangleTextureMap_type; }
@@ -17255,7 +17255,7 @@ Ifc4x3_rc1::IfcIndexedTriangleTextureMap::IfcIndexedTriangleTextureMap(aggregate
 
 // Function implementations for IfcInterceptor
 boost::optional< ::Ifc4x3_rc1::IfcInterceptorTypeEnum::Value > Ifc4x3_rc1::IfcInterceptor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcInterceptorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcInterceptorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcInterceptorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcInterceptor::declaration() const { return *IFC4X3_RC1_IfcInterceptor_type; }
@@ -17283,13 +17283,13 @@ Ifc4x3_rc1::IfcIntersectionCurve::IfcIntersectionCurve(::Ifc4x3_rc1::IfcCurve* v
 
 // Function implementations for IfcInventory
 boost::optional< ::Ifc4x3_rc1::IfcInventoryTypeEnum::Value > Ifc4x3_rc1::IfcInventory::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcInventoryTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc1::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcInventoryTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcInventoryTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc1::IfcActorSelect* Ifc4x3_rc1::IfcInventory::Jurisdiction() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcActorSelect>(true); }
 void Ifc4x3_rc1::IfcInventory::setJurisdiction(::Ifc4x3_rc1::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPerson >::ptr > Ifc4x3_rc1::IfcInventory::ResponsiblePersons() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc1::IfcPerson >(); }
-void Ifc4x3_rc1::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcInventory::LastUpdateDate() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc1::IfcCostValue* Ifc4x3_rc1::IfcInventory::CurrentValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc1::IfcCostValue>(true); }
 void Ifc4x3_rc1::IfcInventory::setCurrentValue(::Ifc4x3_rc1::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x3_rc1::IfcCostValue* Ifc4x3_rc1::IfcInventory::OriginalValue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc1::IfcCostValue>(true); }
@@ -17325,7 +17325,7 @@ Ifc4x3_rc1::IfcIrregularTimeSeriesValue::IfcIrregularTimeSeriesValue(std::string
 
 // Function implementations for IfcJunctionBox
 boost::optional< ::Ifc4x3_rc1::IfcJunctionBoxTypeEnum::Value > Ifc4x3_rc1::IfcJunctionBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcJunctionBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcJunctionBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcJunctionBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcJunctionBox::declaration() const { return *IFC4X3_RC1_IfcJunctionBox_type; }
@@ -17367,15 +17367,15 @@ Ifc4x3_rc1::IfcKerbType::IfcKerbType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 double Ifc4x3_rc1::IfcLShapeProfileDef::Depth() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcLShapeProfileDef::setDepth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcLShapeProfileDef::Width() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 double Ifc4x3_rc1::IfcLShapeProfileDef::Thickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc1::IfcLShapeProfileDef::setThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcLShapeProfileDef::FilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcLShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcLShapeProfileDef::LegSlope() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcLShapeProfileDef::declaration() const { return *IFC4X3_RC1_IfcLShapeProfileDef_type; }
@@ -17385,7 +17385,7 @@ Ifc4x3_rc1::IfcLShapeProfileDef::IfcLShapeProfileDef(::Ifc4x3_rc1::IfcProfileTyp
 
 // Function implementations for IfcLaborResource
 boost::optional< ::Ifc4x3_rc1::IfcLaborResourceTypeEnum::Value > Ifc4x3_rc1::IfcLaborResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcLaborResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcLaborResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcLaborResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcLaborResource::declaration() const { return *IFC4X3_RC1_IfcLaborResource_type; }
@@ -17417,7 +17417,7 @@ Ifc4x3_rc1::IfcLagTime::IfcLagTime(boost::optional< std::string > v1_Name, boost
 
 // Function implementations for IfcLamp
 boost::optional< ::Ifc4x3_rc1::IfcLampTypeEnum::Value > Ifc4x3_rc1::IfcLamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcLampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcLampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcLampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcLamp::declaration() const { return *IFC4X3_RC1_IfcLamp_type; }
@@ -17439,15 +17439,15 @@ Ifc4x3_rc1::IfcLampType::IfcLampType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 std::string Ifc4x3_rc1::IfcLibraryInformation::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcLibraryInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcLibraryInformation::Version() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc1::IfcActorSelect* Ifc4x3_rc1::IfcLibraryInformation::Publisher() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc1::IfcActorSelect>(true); }
 void Ifc4x3_rc1::IfcLibraryInformation::setPublisher(::Ifc4x3_rc1::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcLibraryInformation::VersionDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcLibraryInformation::Location() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcLibraryInformation::Description() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc1::IfcRelAssociatesLibrary::list::ptr Ifc4x3_rc1::IfcLibraryInformation::LibraryInfoForObjects() const { return data_->getInverse(IFC4X3_RC1_IfcRelAssociatesLibrary_type, 5)->as<IfcRelAssociatesLibrary>(); }
 ::Ifc4x3_rc1::IfcLibraryReference::list::ptr Ifc4x3_rc1::IfcLibraryInformation::HasLibraryReferences() const { return data_->getInverse(IFC4X3_RC1_IfcLibraryReference_type, 5)->as<IfcLibraryReference>(); }
@@ -17459,9 +17459,9 @@ Ifc4x3_rc1::IfcLibraryInformation::IfcLibraryInformation(std::string v1_Name, bo
 
 // Function implementations for IfcLibraryReference
 boost::optional< std::string > Ifc4x3_rc1::IfcLibraryReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcLibraryReference::Language() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc1::IfcLibraryInformation* Ifc4x3_rc1::IfcLibraryReference::ReferencedLibrary() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc1::IfcLibraryInformation>(true); }
 void Ifc4x3_rc1::IfcLibraryReference::setReferencedLibrary(::Ifc4x3_rc1::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -17488,7 +17488,7 @@ Ifc4x3_rc1::IfcLightDistributionData::IfcLightDistributionData(double v1_MainPla
 
 // Function implementations for IfcLightFixture
 boost::optional< ::Ifc4x3_rc1::IfcLightFixtureTypeEnum::Value > Ifc4x3_rc1::IfcLightFixture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcLightFixtureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcLightFixtureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcLightFixtureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcLightFixture::declaration() const { return *IFC4X3_RC1_IfcLightFixture_type; }
@@ -17520,13 +17520,13 @@ Ifc4x3_rc1::IfcLightIntensityDistribution::IfcLightIntensityDistribution(::Ifc4x
 
 // Function implementations for IfcLightSource
 boost::optional< std::string > Ifc4x3_rc1::IfcLightSource::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc1::IfcColourRgb* Ifc4x3_rc1::IfcLightSource::LightColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc1::IfcColourRgb>(true); }
 void Ifc4x3_rc1::IfcLightSource::setLightColour(::Ifc4x3_rc1::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcLightSource::AmbientIntensity() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcLightSource::Intensity() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcLightSource::declaration() const { return *IFC4X3_RC1_IfcLightSource_type; }
@@ -17594,7 +17594,7 @@ Ifc4x3_rc1::IfcLightSourcePositional::IfcLightSourcePositional(boost::optional<
 ::Ifc4x3_rc1::IfcDirection* Ifc4x3_rc1::IfcLightSourceSpot::Orientation() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc1::IfcDirection>(true); }
 void Ifc4x3_rc1::IfcLightSourceSpot::setOrientation(::Ifc4x3_rc1::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcLightSourceSpot::ConcentrationExponent() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 double Ifc4x3_rc1::IfcLightSourceSpot::SpreadAngle() const {  double v = *data_->getArgument(11); return v; }
 void Ifc4x3_rc1::IfcLightSourceSpot::setSpreadAngle(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 double Ifc4x3_rc1::IfcLightSourceSpot::BeamWidthAngle() const {  double v = *data_->getArgument(12); return v; }
@@ -17686,7 +17686,7 @@ Ifc4x3_rc1::IfcLinearSpanPlacement::IfcLinearSpanPlacement(::Ifc4x3_rc1::IfcObje
 
 // Function implementations for IfcLiquidTerminal
 boost::optional< ::Ifc4x3_rc1::IfcLiquidTerminalTypeEnum::Value > Ifc4x3_rc1::IfcLiquidTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcLiquidTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcLiquidTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcLiquidTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcLiquidTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcLiquidTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcLiquidTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcLiquidTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcLiquidTerminal::declaration() const { return *IFC4X3_RC1_IfcLiquidTerminal_type; }
@@ -17740,11 +17740,11 @@ void Ifc4x3_rc1::IfcMapConversion::setNorthings(double v) { {IfcWrite::IfcWriteA
 double Ifc4x3_rc1::IfcMapConversion::OrthogonalHeight() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc1::IfcMapConversion::setOrthogonalHeight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcMapConversion::XAxisAbscissa() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcMapConversion::XAxisOrdinate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcMapConversion::Scale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMapConversion::declaration() const { return *IFC4X3_RC1_IfcMapConversion_type; }
@@ -17778,9 +17778,9 @@ Ifc4x3_rc1::IfcMarineFacility::IfcMarineFacility(std::string v1_GlobalId, ::Ifc4
 std::string Ifc4x3_rc1::IfcMaterial::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcMaterial::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterial::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterial::Category() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc1::IfcMaterialDefinitionRepresentation::list::ptr Ifc4x3_rc1::IfcMaterial::HasRepresentation() const { return data_->getInverse(IFC4X3_RC1_IfcMaterialDefinitionRepresentation_type, 3)->as<IfcMaterialDefinitionRepresentation>(); }
 ::Ifc4x3_rc1::IfcMaterialRelationship::list::ptr Ifc4x3_rc1::IfcMaterial::IsRelatedWith() const { return data_->getInverse(IFC4X3_RC1_IfcMaterialRelationship_type, 3)->as<IfcMaterialRelationship>(); }
@@ -17805,15 +17805,15 @@ Ifc4x3_rc1::IfcMaterialClassificationRelationship::IfcMaterialClassificationRela
 
 // Function implementations for IfcMaterialConstituent
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialConstituent::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialConstituent::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc1::IfcMaterial* Ifc4x3_rc1::IfcMaterialConstituent::Material() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc1::IfcMaterial>(true); }
 void Ifc4x3_rc1::IfcMaterialConstituent::setMaterial(::Ifc4x3_rc1::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcMaterialConstituent::Fraction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialConstituent::Category() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc1::IfcMaterialConstituentSet::list::ptr Ifc4x3_rc1::IfcMaterialConstituent::ToMaterialConstituentSet() const { return data_->getInverse(IFC4X3_RC1_IfcMaterialConstituentSet_type, 2)->as<IfcMaterialConstituentSet>(); }
 
@@ -17824,11 +17824,11 @@ Ifc4x3_rc1::IfcMaterialConstituent::IfcMaterialConstituent(boost::optional< std:
 
 // Function implementations for IfcMaterialConstituentSet
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialConstituentSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialConstituentSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcMaterialConstituent >::ptr > Ifc4x3_rc1::IfcMaterialConstituentSet::MaterialConstituents() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc1::IfcMaterialConstituent >(); }
-void Ifc4x3_rc1::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMaterialConstituentSet::declaration() const { return *IFC4X3_RC1_IfcMaterialConstituentSet_type; }
@@ -17863,15 +17863,15 @@ void Ifc4x3_rc1::IfcMaterialLayer::setMaterial(::Ifc4x3_rc1::IfcMaterial* v) { {
 double Ifc4x3_rc1::IfcMaterialLayer::LayerThickness() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcMaterialLayer::setLayerThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< boost::logic::tribool > Ifc4x3_rc1::IfcMaterialLayer::IsVentilated() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } boost::logic::tribool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialLayer::Name() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialLayer::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialLayer::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x3_rc1::IfcMaterialLayer::Priority() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc1::IfcMaterialLayerSet::list::ptr Ifc4x3_rc1::IfcMaterialLayer::ToMaterialLayerSet() const { return data_->getInverse(IFC4X3_RC1_IfcMaterialLayerSet_type, 0)->as<IfcMaterialLayerSet>(); }
 
@@ -17884,9 +17884,9 @@ Ifc4x3_rc1::IfcMaterialLayer::IfcMaterialLayer(::Ifc4x3_rc1::IfcMaterial* v1_Mat
 aggregate_of< ::Ifc4x3_rc1::IfcMaterialLayer >::ptr Ifc4x3_rc1::IfcMaterialLayerSet::MaterialLayers() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x3_rc1::IfcMaterialLayer >(); }
 void Ifc4x3_rc1::IfcMaterialLayerSet::setMaterialLayers(aggregate_of< ::Ifc4x3_rc1::IfcMaterialLayer >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialLayerSet::LayerSetName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialLayerSet::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMaterialLayerSet::declaration() const { return *IFC4X3_RC1_IfcMaterialLayerSet_type; }
@@ -17904,7 +17904,7 @@ void Ifc4x3_rc1::IfcMaterialLayerSetUsage::setDirectionSense(::Ifc4x3_rc1::IfcDi
 double Ifc4x3_rc1::IfcMaterialLayerSetUsage::OffsetFromReferenceLine() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcMaterialLayerSetUsage::setOffsetFromReferenceLine(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcMaterialLayerSetUsage::ReferenceExtent() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMaterialLayerSetUsage::declaration() const { return *IFC4X3_RC1_IfcMaterialLayerSetUsage_type; }
@@ -17936,17 +17936,17 @@ Ifc4x3_rc1::IfcMaterialList::IfcMaterialList(aggregate_of< ::Ifc4x3_rc1::IfcMate
 
 // Function implementations for IfcMaterialProfile
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialProfile::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialProfile::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc1::IfcMaterial* Ifc4x3_rc1::IfcMaterialProfile::Material() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc1::IfcMaterial>(true); }
 void Ifc4x3_rc1::IfcMaterialProfile::setMaterial(::Ifc4x3_rc1::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcProfileDef* Ifc4x3_rc1::IfcMaterialProfile::Profile() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcProfileDef>(true); }
 void Ifc4x3_rc1::IfcMaterialProfile::setProfile(::Ifc4x3_rc1::IfcProfileDef* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc1::IfcMaterialProfile::Priority() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialProfile::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc1::IfcMaterialProfileSet::list::ptr Ifc4x3_rc1::IfcMaterialProfile::ToMaterialProfileSet() const { return data_->getInverse(IFC4X3_RC1_IfcMaterialProfileSet_type, 2)->as<IfcMaterialProfileSet>(); }
 
@@ -17957,9 +17957,9 @@ Ifc4x3_rc1::IfcMaterialProfile::IfcMaterialProfile(boost::optional< std::string
 
 // Function implementations for IfcMaterialProfileSet
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialProfileSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialProfileSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc1::IfcMaterialProfile >::ptr Ifc4x3_rc1::IfcMaterialProfileSet::MaterialProfiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc1::IfcMaterialProfile >(); }
 void Ifc4x3_rc1::IfcMaterialProfileSet::setMaterialProfiles(aggregate_of< ::Ifc4x3_rc1::IfcMaterialProfile >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcCompositeProfileDef* Ifc4x3_rc1::IfcMaterialProfileSet::CompositeProfile() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcCompositeProfileDef>(true); }
@@ -17975,9 +17975,9 @@ Ifc4x3_rc1::IfcMaterialProfileSet::IfcMaterialProfileSet(boost::optional< std::s
 ::Ifc4x3_rc1::IfcMaterialProfileSet* Ifc4x3_rc1::IfcMaterialProfileSetUsage::ForProfileSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc1::IfcMaterialProfileSet>(true); }
 void Ifc4x3_rc1::IfcMaterialProfileSetUsage::setForProfileSet(::Ifc4x3_rc1::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< int > Ifc4x3_rc1::IfcMaterialProfileSetUsage::CardinalPoint() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } int v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcMaterialProfileSetUsage::ReferenceExtent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMaterialProfileSetUsage::declaration() const { return *IFC4X3_RC1_IfcMaterialProfileSetUsage_type; }
@@ -17989,7 +17989,7 @@ Ifc4x3_rc1::IfcMaterialProfileSetUsage::IfcMaterialProfileSetUsage(::Ifc4x3_rc1:
 ::Ifc4x3_rc1::IfcMaterialProfileSet* Ifc4x3_rc1::IfcMaterialProfileSetUsageTapering::ForProfileEndSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcMaterialProfileSet>(true); }
 void Ifc4x3_rc1::IfcMaterialProfileSetUsageTapering::setForProfileEndSet(::Ifc4x3_rc1::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc1::IfcMaterialProfileSetUsageTapering::CardinalEndPoint() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMaterialProfileSetUsageTapering::declaration() const { return *IFC4X3_RC1_IfcMaterialProfileSetUsageTapering_type; }
@@ -18023,7 +18023,7 @@ void Ifc4x3_rc1::IfcMaterialRelationship::setRelatingMaterial(::Ifc4x3_rc1::IfcM
 aggregate_of< ::Ifc4x3_rc1::IfcMaterial >::ptr Ifc4x3_rc1::IfcMaterialRelationship::RelatedMaterials() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc1::IfcMaterial >(); }
 void Ifc4x3_rc1::IfcMaterialRelationship::setRelatedMaterials(aggregate_of< ::Ifc4x3_rc1::IfcMaterial >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMaterialRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMaterialRelationship::declaration() const { return *IFC4X3_RC1_IfcMaterialRelationship_type; }
@@ -18054,11 +18054,11 @@ Ifc4x3_rc1::IfcMeasureWithUnit::IfcMeasureWithUnit(::Ifc4x3_rc1::IfcValue* v1_Va
 
 // Function implementations for IfcMechanicalFastener
 boost::optional< double > Ifc4x3_rc1::IfcMechanicalFastener::NominalDiameter() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcMechanicalFastener::NominalLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcMechanicalFastenerTypeEnum::Value > Ifc4x3_rc1::IfcMechanicalFastener::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMechanicalFastenerTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMechanicalFastenerTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMechanicalFastener::declaration() const { return *IFC4X3_RC1_IfcMechanicalFastener_type; }
@@ -18070,9 +18070,9 @@ Ifc4x3_rc1::IfcMechanicalFastener::IfcMechanicalFastener(std::string v1_GlobalId
 ::Ifc4x3_rc1::IfcMechanicalFastenerTypeEnum::Value Ifc4x3_rc1::IfcMechanicalFastenerType::PredefinedType() const {  return ::Ifc4x3_rc1::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc1::IfcMechanicalFastenerType::setPredefinedType(::Ifc4x3_rc1::IfcMechanicalFastenerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcMechanicalFastenerTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcMechanicalFastenerType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcMechanicalFastenerType::NominalLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMechanicalFastenerType::declaration() const { return *IFC4X3_RC1_IfcMechanicalFastenerType_type; }
@@ -18082,7 +18082,7 @@ Ifc4x3_rc1::IfcMechanicalFastenerType::IfcMechanicalFastenerType(std::string v1_
 
 // Function implementations for IfcMedicalDevice
 boost::optional< ::Ifc4x3_rc1::IfcMedicalDeviceTypeEnum::Value > Ifc4x3_rc1::IfcMedicalDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcMedicalDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMedicalDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMedicalDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMedicalDevice::declaration() const { return *IFC4X3_RC1_IfcMedicalDevice_type; }
@@ -18102,7 +18102,7 @@ Ifc4x3_rc1::IfcMedicalDeviceType::IfcMedicalDeviceType(std::string v1_GlobalId,
 
 // Function implementations for IfcMember
 boost::optional< ::Ifc4x3_rc1::IfcMemberTypeEnum::Value > Ifc4x3_rc1::IfcMember::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcMemberTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcMember::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMemberTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcMember::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMemberTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMember::declaration() const { return *IFC4X3_RC1_IfcMember_type; }
@@ -18132,7 +18132,7 @@ Ifc4x3_rc1::IfcMemberType::IfcMemberType(std::string v1_GlobalId, ::Ifc4x3_rc1::
 ::Ifc4x3_rc1::IfcBenchmarkEnum::Value Ifc4x3_rc1::IfcMetric::Benchmark() const {  return ::Ifc4x3_rc1::IfcBenchmarkEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc1::IfcMetric::setBenchmark(::Ifc4x3_rc1::IfcBenchmarkEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcBenchmarkEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcMetric::ValueSource() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc1::IfcMetricValueSelect* Ifc4x3_rc1::IfcMetric::DataValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc1::IfcMetricValueSelect>(true); }
 void Ifc4x3_rc1::IfcMetric::setDataValue(::Ifc4x3_rc1::IfcMetricValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x3_rc1::IfcReference* Ifc4x3_rc1::IfcMetric::ReferencePath() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc1::IfcReference>(true); }
@@ -18154,7 +18154,7 @@ Ifc4x3_rc1::IfcMirroredProfileDef::IfcMirroredProfileDef(::Ifc4x3_rc1::IfcProfil
 
 // Function implementations for IfcMobileTelecommunicationsAppliance
 boost::optional< ::Ifc4x3_rc1::IfcMobileTelecommunicationsApplianceTypeEnum::Value > Ifc4x3_rc1::IfcMobileTelecommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcMobileTelecommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcMobileTelecommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMobileTelecommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMobileTelecommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcMobileTelecommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMobileTelecommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMobileTelecommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMobileTelecommunicationsAppliance::declaration() const { return *IFC4X3_RC1_IfcMobileTelecommunicationsAppliance_type; }
@@ -18184,7 +18184,7 @@ Ifc4x3_rc1::IfcMonetaryUnit::IfcMonetaryUnit(std::string v1_Currency) : IfcUtil:
 
 // Function implementations for IfcMooringDevice
 boost::optional< ::Ifc4x3_rc1::IfcMooringDeviceTypeEnum::Value > Ifc4x3_rc1::IfcMooringDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcMooringDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcMooringDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMooringDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMooringDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcMooringDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMooringDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMooringDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMooringDevice::declaration() const { return *IFC4X3_RC1_IfcMooringDevice_type; }
@@ -18204,7 +18204,7 @@ Ifc4x3_rc1::IfcMooringDeviceType::IfcMooringDeviceType(std::string v1_GlobalId,
 
 // Function implementations for IfcMotorConnection
 boost::optional< ::Ifc4x3_rc1::IfcMotorConnectionTypeEnum::Value > Ifc4x3_rc1::IfcMotorConnection::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcMotorConnectionTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMotorConnectionTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcMotorConnectionTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcMotorConnection::declaration() const { return *IFC4X3_RC1_IfcMotorConnection_type; }
@@ -18236,7 +18236,7 @@ Ifc4x3_rc1::IfcNamedUnit::IfcNamedUnit(::Ifc4x3_rc1::IfcDimensionalExponents* v1
 
 // Function implementations for IfcNavigationElement
 boost::optional< ::Ifc4x3_rc1::IfcNavigationElementTypeEnum::Value > Ifc4x3_rc1::IfcNavigationElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcNavigationElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcNavigationElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcNavigationElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcNavigationElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcNavigationElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcNavigationElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcNavigationElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcNavigationElement::declaration() const { return *IFC4X3_RC1_IfcNavigationElement_type; }
@@ -18256,7 +18256,7 @@ Ifc4x3_rc1::IfcNavigationElementType::IfcNavigationElementType(std::string v1_Gl
 
 // Function implementations for IfcObject
 boost::optional< std::string > Ifc4x3_rc1::IfcObject::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc1::IfcRelDefinesByObject::list::ptr Ifc4x3_rc1::IfcObject::IsDeclaredBy() const { return data_->getInverse(IFC4X3_RC1_IfcRelDefinesByObject_type, 4)->as<IfcRelDefinesByObject>(); }
 ::Ifc4x3_rc1::IfcRelDefinesByObject::list::ptr Ifc4x3_rc1::IfcObject::Declares() const { return data_->getInverse(IFC4X3_RC1_IfcRelDefinesByObject_type, 5)->as<IfcRelDefinesByObject>(); }
@@ -18296,13 +18296,13 @@ Ifc4x3_rc1::IfcObjectPlacement::IfcObjectPlacement(::Ifc4x3_rc1::IfcObjectPlacem
 
 // Function implementations for IfcObjective
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcConstraint >::ptr > Ifc4x3_rc1::IfcObjective::BenchmarkValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc1::IfcConstraint >(); }
-void Ifc4x3_rc1::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcLogicalOperatorEnum::Value > Ifc4x3_rc1::IfcObjective::LogicalAggregator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcLogicalOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x3_rc1::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcLogicalOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x3_rc1::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcLogicalOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc1::IfcObjectiveEnum::Value Ifc4x3_rc1::IfcObjective::ObjectiveQualifier() const {  return ::Ifc4x3_rc1::IfcObjectiveEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc1::IfcObjective::setObjectiveQualifier(::Ifc4x3_rc1::IfcObjectiveEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcObjectiveEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcObjective::UserDefinedQualifier() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcObjective::declaration() const { return *IFC4X3_RC1_IfcObjective_type; }
@@ -18312,7 +18312,7 @@ Ifc4x3_rc1::IfcObjective::IfcObjective(std::string v1_Name, boost::optional< std
 
 // Function implementations for IfcOccupant
 boost::optional< ::Ifc4x3_rc1::IfcOccupantTypeEnum::Value > Ifc4x3_rc1::IfcOccupant::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcOccupantTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc1::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcOccupantTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcOccupantTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcOccupant::declaration() const { return *IFC4X3_RC1_IfcOccupant_type; }
@@ -18360,7 +18360,7 @@ Ifc4x3_rc1::IfcOffsetCurve3D::IfcOffsetCurve3D(::Ifc4x3_rc1::IfcCurve* v1_BasisC
 aggregate_of< ::Ifc4x3_rc1::IfcDistanceExpression >::ptr Ifc4x3_rc1::IfcOffsetCurveByDistances::OffsetValues() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc1::IfcDistanceExpression >(); }
 void Ifc4x3_rc1::IfcOffsetCurveByDistances::setOffsetValues(aggregate_of< ::Ifc4x3_rc1::IfcDistanceExpression >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcOffsetCurveByDistances::Tag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcOffsetCurveByDistances::declaration() const { return *IFC4X3_RC1_IfcOffsetCurveByDistances_type; }
@@ -18376,7 +18376,7 @@ void Ifc4x3_rc1::IfcOpenCrossProfileDef::setWidths(std::vector< double > /*[1:?]
 std::vector< double > /*[1:?]*/ Ifc4x3_rc1::IfcOpenCrossProfileDef::Slopes() const {  std::vector< double > /*[1:?]*/ v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc1::IfcOpenCrossProfileDef::setSlopes(std::vector< double > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[2:?]*/ > Ifc4x3_rc1::IfcOpenCrossProfileDef::Tags() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[2:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcOpenCrossProfileDef::setTags(boost::optional< std::vector< std::string > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcOpenCrossProfileDef::setTags(boost::optional< std::vector< std::string > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcOpenCrossProfileDef::declaration() const { return *IFC4X3_RC1_IfcOpenCrossProfileDef_type; }
@@ -18394,7 +18394,7 @@ Ifc4x3_rc1::IfcOpenShell::IfcOpenShell(aggregate_of< ::Ifc4x3_rc1::IfcFace >::pt
 
 // Function implementations for IfcOpeningElement
 boost::optional< ::Ifc4x3_rc1::IfcOpeningElementTypeEnum::Value > Ifc4x3_rc1::IfcOpeningElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcOpeningElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcOpeningElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcOpeningElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc1::IfcRelFillsElement::list::ptr Ifc4x3_rc1::IfcOpeningElement::HasFillings() const { return data_->getInverse(IFC4X3_RC1_IfcRelFillsElement_type, 4)->as<IfcRelFillsElement>(); }
 
@@ -18413,15 +18413,15 @@ Ifc4x3_rc1::IfcOpeningStandardCase::IfcOpeningStandardCase(std::string v1_Global
 
 // Function implementations for IfcOrganization
 boost::optional< std::string > Ifc4x3_rc1::IfcOrganization::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 std::string Ifc4x3_rc1::IfcOrganization::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcOrganization::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcOrganization::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcActorRole >::ptr > Ifc4x3_rc1::IfcOrganization::Roles() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc1::IfcActorRole >(); }
-void Ifc4x3_rc1::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(3,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAddress >::ptr > Ifc4x3_rc1::IfcOrganization::Addresses() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x3_rc1::IfcAddress >(); }
-void Ifc4x3_rc1::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc1::IfcOrganizationRelationship::list::ptr Ifc4x3_rc1::IfcOrganization::IsRelatedBy() const { return data_->getInverse(IFC4X3_RC1_IfcOrganizationRelationship_type, 3)->as<IfcOrganizationRelationship>(); }
 ::Ifc4x3_rc1::IfcOrganizationRelationship::list::ptr Ifc4x3_rc1::IfcOrganization::Relates() const { return data_->getInverse(IFC4X3_RC1_IfcOrganizationRelationship_type, 2)->as<IfcOrganizationRelationship>(); }
@@ -18478,7 +18478,7 @@ Ifc4x3_rc1::IfcOuterBoundaryCurve::IfcOuterBoundaryCurve(aggregate_of< ::Ifc4x3_
 
 // Function implementations for IfcOutlet
 boost::optional< ::Ifc4x3_rc1::IfcOutletTypeEnum::Value > Ifc4x3_rc1::IfcOutlet::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcOutletTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcOutletTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcOutletTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcOutlet::declaration() const { return *IFC4X3_RC1_IfcOutlet_type; }
@@ -18502,11 +18502,11 @@ void Ifc4x3_rc1::IfcOwnerHistory::setOwningUser(::Ifc4x3_rc1::IfcPersonAndOrgani
 ::Ifc4x3_rc1::IfcApplication* Ifc4x3_rc1::IfcOwnerHistory::OwningApplication() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc1::IfcApplication>(true); }
 void Ifc4x3_rc1::IfcOwnerHistory::setOwningApplication(::Ifc4x3_rc1::IfcApplication* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcStateEnum::Value > Ifc4x3_rc1::IfcOwnerHistory::State() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcStateEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc1::IfcOwnerHistory::setState(boost::optional< ::Ifc4x3_rc1::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcStateEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcOwnerHistory::setState(boost::optional< ::Ifc4x3_rc1::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcStateEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcChangeActionEnum::Value > Ifc4x3_rc1::IfcOwnerHistory::ChangeAction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcChangeActionEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x3_rc1::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x3_rc1::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcChangeActionEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x3_rc1::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcChangeActionEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc1::IfcOwnerHistory::LastModifiedDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc1::IfcPersonAndOrganization* Ifc4x3_rc1::IfcOwnerHistory::LastModifyingUser() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc1::IfcPersonAndOrganization>(true); }
 void Ifc4x3_rc1::IfcOwnerHistory::setLastModifyingUser(::Ifc4x3_rc1::IfcPersonAndOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x3_rc1::IfcApplication* Ifc4x3_rc1::IfcOwnerHistory::LastModifyingApplication() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcApplication>(true); }
@@ -18542,7 +18542,7 @@ Ifc4x3_rc1::IfcPath::IfcPath(aggregate_of< ::Ifc4x3_rc1::IfcOrientedEdge >::ptr
 
 // Function implementations for IfcPavement
 boost::optional< bool > Ifc4x3_rc1::IfcPavement::Flexible() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } bool v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcPavement::setFlexible(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcPavement::setFlexible(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPavement::declaration() const { return *IFC4X3_RC1_IfcPavement_type; }
@@ -18576,7 +18576,7 @@ Ifc4x3_rc1::IfcPcurve::IfcPcurve(::Ifc4x3_rc1::IfcSurface* v1_BasisSurface, ::If
 std::string Ifc4x3_rc1::IfcPerformanceHistory::LifeCyclePhase() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc1::IfcPerformanceHistory::setLifeCyclePhase(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcPerformanceHistoryTypeEnum::Value > Ifc4x3_rc1::IfcPerformanceHistory::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcPerformanceHistoryTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc1::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPerformanceHistoryTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPerformanceHistoryTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPerformanceHistory::declaration() const { return *IFC4X3_RC1_IfcPerformanceHistory_type; }
@@ -18590,9 +18590,9 @@ void Ifc4x3_rc1::IfcPermeableCoveringProperties::setOperationType(::Ifc4x3_rc1::
 ::Ifc4x3_rc1::IfcWindowPanelPositionEnum::Value Ifc4x3_rc1::IfcPermeableCoveringProperties::PanelPosition() const {  return ::Ifc4x3_rc1::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc1::IfcPermeableCoveringProperties::setPanelPosition(::Ifc4x3_rc1::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcPermeableCoveringProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcPermeableCoveringProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc1::IfcShapeAspect* Ifc4x3_rc1::IfcPermeableCoveringProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc1::IfcShapeAspect>(true); }
 void Ifc4x3_rc1::IfcPermeableCoveringProperties::setShapeAspectStyle(::Ifc4x3_rc1::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -18604,11 +18604,11 @@ Ifc4x3_rc1::IfcPermeableCoveringProperties::IfcPermeableCoveringProperties(std::
 
 // Function implementations for IfcPermit
 boost::optional< ::Ifc4x3_rc1::IfcPermitTypeEnum::Value > Ifc4x3_rc1::IfcPermit::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcPermitTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc1::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPermitTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPermitTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPermit::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPermit::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPermit::declaration() const { return *IFC4X3_RC1_IfcPermit_type; }
@@ -18618,21 +18618,21 @@ Ifc4x3_rc1::IfcPermit::IfcPermit(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwner
 
 // Function implementations for IfcPerson
 boost::optional< std::string > Ifc4x3_rc1::IfcPerson::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPerson::FamilyName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPerson::GivenName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcPerson::MiddleNames() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcPerson::PrefixTitles() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcPerson::SuffixTitles() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcActorRole >::ptr > Ifc4x3_rc1::IfcPerson::Roles() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc1::IfcActorRole >(); }
-void Ifc4x3_rc1::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAddress >::ptr > Ifc4x3_rc1::IfcPerson::Addresses() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc1::IfcAddress >(); }
-void Ifc4x3_rc1::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc1::IfcPersonAndOrganization::list::ptr Ifc4x3_rc1::IfcPerson::EngagedIn() const { return data_->getInverse(IFC4X3_RC1_IfcPersonAndOrganization_type, 0)->as<IfcPersonAndOrganization>(); }
 
@@ -18647,7 +18647,7 @@ void Ifc4x3_rc1::IfcPersonAndOrganization::setThePerson(::Ifc4x3_rc1::IfcPerson*
 ::Ifc4x3_rc1::IfcOrganization* Ifc4x3_rc1::IfcPersonAndOrganization::TheOrganization() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc1::IfcOrganization>(true); }
 void Ifc4x3_rc1::IfcPersonAndOrganization::setTheOrganization(::Ifc4x3_rc1::IfcOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcActorRole >::ptr > Ifc4x3_rc1::IfcPersonAndOrganization::Roles() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc1::IfcActorRole >(); }
-void Ifc4x3_rc1::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPersonAndOrganization::declaration() const { return *IFC4X3_RC1_IfcPersonAndOrganization_type; }
@@ -18661,9 +18661,9 @@ void Ifc4x3_rc1::IfcPhysicalComplexQuantity::setHasQuantities(aggregate_of< ::If
 std::string Ifc4x3_rc1::IfcPhysicalComplexQuantity::Discrimination() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcPhysicalComplexQuantity::setDiscrimination(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPhysicalComplexQuantity::Quality() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPhysicalComplexQuantity::Usage() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPhysicalComplexQuantity::declaration() const { return *IFC4X3_RC1_IfcPhysicalComplexQuantity_type; }
@@ -18675,7 +18675,7 @@ Ifc4x3_rc1::IfcPhysicalComplexQuantity::IfcPhysicalComplexQuantity(std::string v
 std::string Ifc4x3_rc1::IfcPhysicalQuantity::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcPhysicalQuantity::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPhysicalQuantity::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc1::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc1::IfcPhysicalQuantity::HasExternalReferences() const { return data_->getInverse(IFC4X3_RC1_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc1::IfcPhysicalComplexQuantity::list::ptr Ifc4x3_rc1::IfcPhysicalQuantity::PartOfComplex() const { return data_->getInverse(IFC4X3_RC1_IfcPhysicalComplexQuantity_type, 2)->as<IfcPhysicalComplexQuantity>(); }
@@ -18697,9 +18697,9 @@ Ifc4x3_rc1::IfcPhysicalSimpleQuantity::IfcPhysicalSimpleQuantity(std::string v1_
 
 // Function implementations for IfcPile
 boost::optional< ::Ifc4x3_rc1::IfcPileTypeEnum::Value > Ifc4x3_rc1::IfcPile::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcPileTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcPile::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPileTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcPile::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPileTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcPileConstructionEnum::Value > Ifc4x3_rc1::IfcPile::ConstructionType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcPileConstructionEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc1::IfcPile::setConstructionType(boost::optional< ::Ifc4x3_rc1::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPileConstructionEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcPile::setConstructionType(boost::optional< ::Ifc4x3_rc1::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPileConstructionEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPile::declaration() const { return *IFC4X3_RC1_IfcPile_type; }
@@ -18719,7 +18719,7 @@ Ifc4x3_rc1::IfcPileType::IfcPileType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcPipeFitting
 boost::optional< ::Ifc4x3_rc1::IfcPipeFittingTypeEnum::Value > Ifc4x3_rc1::IfcPipeFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcPipeFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPipeFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPipeFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPipeFitting::declaration() const { return *IFC4X3_RC1_IfcPipeFitting_type; }
@@ -18739,7 +18739,7 @@ Ifc4x3_rc1::IfcPipeFittingType::IfcPipeFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcPipeSegment
 boost::optional< ::Ifc4x3_rc1::IfcPipeSegmentTypeEnum::Value > Ifc4x3_rc1::IfcPipeSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcPipeSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPipeSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPipeSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPipeSegment::declaration() const { return *IFC4X3_RC1_IfcPipeSegment_type; }
@@ -18823,7 +18823,7 @@ Ifc4x3_rc1::IfcPlant::IfcPlant(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHi
 
 // Function implementations for IfcPlate
 boost::optional< ::Ifc4x3_rc1::IfcPlateTypeEnum::Value > Ifc4x3_rc1::IfcPlate::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcPlateTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPlateTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPlateTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPlate::declaration() const { return *IFC4X3_RC1_IfcPlate_type; }
@@ -18907,11 +18907,11 @@ Ifc4x3_rc1::IfcPolygonalBoundedHalfSpace::IfcPolygonalBoundedHalfSpace(::Ifc4x3_
 
 // Function implementations for IfcPolygonalFaceSet
 boost::optional< bool > Ifc4x3_rc1::IfcPolygonalFaceSet::Closed() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc1::IfcIndexedPolygonalFace >::ptr Ifc4x3_rc1::IfcPolygonalFaceSet::Faces() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc1::IfcIndexedPolygonalFace >(); }
 void Ifc4x3_rc1::IfcPolygonalFaceSet::setFaces(aggregate_of< ::Ifc4x3_rc1::IfcIndexedPolygonalFace >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc1::IfcPolygonalFaceSet::PnIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPolygonalFaceSet::declaration() const { return *IFC4X3_RC1_IfcPolygonalFaceSet_type; }
@@ -18952,19 +18952,19 @@ Ifc4x3_rc1::IfcPositioningElement::IfcPositioningElement(std::string v1_GlobalId
 
 // Function implementations for IfcPostalAddress
 boost::optional< std::string > Ifc4x3_rc1::IfcPostalAddress::InternalLocation() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcPostalAddress::AddressLines() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPostalAddress::PostalBox() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPostalAddress::Town() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPostalAddress::Region() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPostalAddress::PostalCode() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPostalAddress::Country() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPostalAddress::declaration() const { return *IFC4X3_RC1_IfcPostalAddress_type; }
@@ -19034,11 +19034,11 @@ Ifc4x3_rc1::IfcPresentationItem::IfcPresentationItem() : IfcUtil::IfcBaseEntity(
 std::string Ifc4x3_rc1::IfcPresentationLayerAssignment::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcPresentationLayerAssignment::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPresentationLayerAssignment::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of_instance::ptr Ifc4x3_rc1::IfcPresentationLayerAssignment::AssignedItems() const {  aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc1::IfcPresentationLayerAssignment::setAssignedItems(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPresentationLayerAssignment::Identifier() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPresentationLayerAssignment::declaration() const { return *IFC4X3_RC1_IfcPresentationLayerAssignment_type; }
@@ -19064,7 +19064,7 @@ Ifc4x3_rc1::IfcPresentationLayerWithStyle::IfcPresentationLayerWithStyle(std::st
 
 // Function implementations for IfcPresentationStyle
 boost::optional< std::string > Ifc4x3_rc1::IfcPresentationStyle::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPresentationStyle::declaration() const { return *IFC4X3_RC1_IfcPresentationStyle_type; }
@@ -19084,7 +19084,7 @@ Ifc4x3_rc1::IfcPresentationStyleAssignment::IfcPresentationStyleAssignment(aggre
 
 // Function implementations for IfcProcedure
 boost::optional< ::Ifc4x3_rc1::IfcProcedureTypeEnum::Value > Ifc4x3_rc1::IfcProcedure::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcProcedureTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc1::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProcedureTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProcedureTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcProcedure::declaration() const { return *IFC4X3_RC1_IfcProcedure_type; }
@@ -19104,9 +19104,9 @@ Ifc4x3_rc1::IfcProcedureType::IfcProcedureType(std::string v1_GlobalId, ::Ifc4x3
 
 // Function implementations for IfcProcess
 boost::optional< std::string > Ifc4x3_rc1::IfcProcess::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcProcess::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc1::IfcRelSequence::list::ptr Ifc4x3_rc1::IfcProcess::IsPredecessorTo() const { return data_->getInverse(IFC4X3_RC1_IfcRelSequence_type, 4)->as<IfcRelSequence>(); }
 ::Ifc4x3_rc1::IfcRelSequence::list::ptr Ifc4x3_rc1::IfcProcess::IsSuccessorFrom() const { return data_->getInverse(IFC4X3_RC1_IfcRelSequence_type, 5)->as<IfcRelSequence>(); }
@@ -19144,9 +19144,9 @@ Ifc4x3_rc1::IfcProductDefinitionShape::IfcProductDefinitionShape(boost::optional
 
 // Function implementations for IfcProductRepresentation
 boost::optional< std::string > Ifc4x3_rc1::IfcProductRepresentation::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcProductRepresentation::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc1::IfcRepresentation >::ptr Ifc4x3_rc1::IfcProductRepresentation::Representations() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc1::IfcRepresentation >(); }
 void Ifc4x3_rc1::IfcProductRepresentation::setRepresentations(aggregate_of< ::Ifc4x3_rc1::IfcRepresentation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -19160,7 +19160,7 @@ Ifc4x3_rc1::IfcProductRepresentation::IfcProductRepresentation(boost::optional<
 ::Ifc4x3_rc1::IfcProfileTypeEnum::Value Ifc4x3_rc1::IfcProfileDef::ProfileType() const {  return ::Ifc4x3_rc1::IfcProfileTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc1::IfcProfileDef::setProfileType(::Ifc4x3_rc1::IfcProfileTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcProfileTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcProfileDef::ProfileName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc1::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc1::IfcProfileDef::HasExternalReference() const { return data_->getInverse(IFC4X3_RC1_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc1::IfcProfileProperties::list::ptr Ifc4x3_rc1::IfcProfileDef::HasProperties() const { return data_->getInverse(IFC4X3_RC1_IfcProfileProperties_type, 3)->as<IfcProfileProperties>(); }
@@ -19198,11 +19198,11 @@ Ifc4x3_rc1::IfcProjectLibrary::IfcProjectLibrary(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcProjectOrder
 boost::optional< ::Ifc4x3_rc1::IfcProjectOrderTypeEnum::Value > Ifc4x3_rc1::IfcProjectOrder::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcProjectOrderTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc1::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProjectOrderTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProjectOrderTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcProjectOrder::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcProjectOrder::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcProjectOrder::declaration() const { return *IFC4X3_RC1_IfcProjectOrder_type; }
@@ -19212,9 +19212,9 @@ Ifc4x3_rc1::IfcProjectOrder::IfcProjectOrder(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcProjectedCRS
 boost::optional< std::string > Ifc4x3_rc1::IfcProjectedCRS::MapProjection() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcProjectedCRS::MapZone() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc1::IfcNamedUnit* Ifc4x3_rc1::IfcProjectedCRS::MapUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcNamedUnit>(true); }
 void Ifc4x3_rc1::IfcProjectedCRS::setMapUnit(::Ifc4x3_rc1::IfcNamedUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -19226,7 +19226,7 @@ Ifc4x3_rc1::IfcProjectedCRS::IfcProjectedCRS(std::string v1_Name, boost::optiona
 
 // Function implementations for IfcProjectionElement
 boost::optional< ::Ifc4x3_rc1::IfcProjectionElementTypeEnum::Value > Ifc4x3_rc1::IfcProjectionElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcProjectionElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProjectionElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProjectionElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcProjectionElement::declaration() const { return *IFC4X3_RC1_IfcProjectionElement_type; }
@@ -19238,7 +19238,7 @@ Ifc4x3_rc1::IfcProjectionElement::IfcProjectionElement(std::string v1_GlobalId,
 std::string Ifc4x3_rc1::IfcProperty::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcProperty::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcProperty::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc1::IfcPropertySet::list::ptr Ifc4x3_rc1::IfcProperty::PartOfPset() const { return data_->getInverse(IFC4X3_RC1_IfcPropertySet_type, 4)->as<IfcPropertySet>(); }
 ::Ifc4x3_rc1::IfcPropertyDependencyRelationship::list::ptr Ifc4x3_rc1::IfcProperty::PropertyForDependance() const { return data_->getInverse(IFC4X3_RC1_IfcPropertyDependencyRelationship_type, 2)->as<IfcPropertyDependencyRelationship>(); }
@@ -19293,7 +19293,7 @@ void Ifc4x3_rc1::IfcPropertyDependencyRelationship::setDependingProperty(::Ifc4x
 ::Ifc4x3_rc1::IfcProperty* Ifc4x3_rc1::IfcPropertyDependencyRelationship::DependantProperty() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcProperty>(true); }
 void Ifc4x3_rc1::IfcPropertyDependencyRelationship::setDependantProperty(::Ifc4x3_rc1::IfcProperty* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPropertyDependencyRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPropertyDependencyRelationship::declaration() const { return *IFC4X3_RC1_IfcPropertyDependencyRelationship_type; }
@@ -19303,7 +19303,7 @@ Ifc4x3_rc1::IfcPropertyDependencyRelationship::IfcPropertyDependencyRelationship
 
 // Function implementations for IfcPropertyEnumeratedValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc1::IfcPropertyEnumeratedValue::EnumerationValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcPropertyEnumeration* Ifc4x3_rc1::IfcPropertyEnumeratedValue::EnumerationReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcPropertyEnumeration>(true); }
 void Ifc4x3_rc1::IfcPropertyEnumeratedValue::setEnumerationReference(::Ifc4x3_rc1::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19329,7 +19329,7 @@ Ifc4x3_rc1::IfcPropertyEnumeration::IfcPropertyEnumeration(std::string v1_Name,
 
 // Function implementations for IfcPropertyListValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc1::IfcPropertyListValue::ListValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcUnit* Ifc4x3_rc1::IfcPropertyListValue::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcUnit>(true); }
 void Ifc4x3_rc1::IfcPropertyListValue::setUnit(::Ifc4x3_rc1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19341,7 +19341,7 @@ Ifc4x3_rc1::IfcPropertyListValue::IfcPropertyListValue(std::string v1_Name, boos
 
 // Function implementations for IfcPropertyReferenceValue
 boost::optional< std::string > Ifc4x3_rc1::IfcPropertyReferenceValue::UsageName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcObjectReferenceSelect* Ifc4x3_rc1::IfcPropertyReferenceValue::PropertyReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcObjectReferenceSelect>(true); }
 void Ifc4x3_rc1::IfcPropertyReferenceValue::setPropertyReference(::Ifc4x3_rc1::IfcObjectReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19374,9 +19374,9 @@ Ifc4x3_rc1::IfcPropertySetDefinition::IfcPropertySetDefinition(std::string v1_Gl
 
 // Function implementations for IfcPropertySetTemplate
 boost::optional< ::Ifc4x3_rc1::IfcPropertySetTemplateTypeEnum::Value > Ifc4x3_rc1::IfcPropertySetTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcPropertySetTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x3_rc1::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc1::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPropertySetTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc1::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPropertySetTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPropertySetTemplate::ApplicableEntity() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 aggregate_of< ::Ifc4x3_rc1::IfcPropertyTemplate >::ptr Ifc4x3_rc1::IfcPropertySetTemplate::HasPropertyTemplates() const {  aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc1::IfcPropertyTemplate >(); }
 void Ifc4x3_rc1::IfcPropertySetTemplate::setHasPropertyTemplates(aggregate_of< ::Ifc4x3_rc1::IfcPropertyTemplate >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(6,attr);} }
 
@@ -19401,17 +19401,17 @@ Ifc4x3_rc1::IfcPropertySingleValue::IfcPropertySingleValue(std::string v1_Name,
 
 // Function implementations for IfcPropertyTableValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc1::IfcPropertyTableValue::DefiningValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc1::IfcPropertyTableValue::DefinedValues() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcPropertyTableValue::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc1::IfcUnit* Ifc4x3_rc1::IfcPropertyTableValue::DefiningUnit() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc1::IfcUnit>(true); }
 void Ifc4x3_rc1::IfcPropertyTableValue::setDefiningUnit(::Ifc4x3_rc1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x3_rc1::IfcUnit* Ifc4x3_rc1::IfcPropertyTableValue::DefinedUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcUnit>(true); }
 void Ifc4x3_rc1::IfcPropertyTableValue::setDefinedUnit(::Ifc4x3_rc1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcCurveInterpolationEnum::Value > Ifc4x3_rc1::IfcPropertyTableValue::CurveInterpolation() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcCurveInterpolationEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc1::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x3_rc1::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCurveInterpolationEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x3_rc1::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcCurveInterpolationEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPropertyTableValue::declaration() const { return *IFC4X3_RC1_IfcPropertyTableValue_type; }
@@ -19439,7 +19439,7 @@ Ifc4x3_rc1::IfcPropertyTemplateDefinition::IfcPropertyTemplateDefinition(std::st
 
 // Function implementations for IfcProtectiveDevice
 boost::optional< ::Ifc4x3_rc1::IfcProtectiveDeviceTypeEnum::Value > Ifc4x3_rc1::IfcProtectiveDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcProtectiveDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProtectiveDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProtectiveDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcProtectiveDevice::declaration() const { return *IFC4X3_RC1_IfcProtectiveDevice_type; }
@@ -19449,7 +19449,7 @@ Ifc4x3_rc1::IfcProtectiveDevice::IfcProtectiveDevice(std::string v1_GlobalId, ::
 
 // Function implementations for IfcProtectiveDeviceTrippingUnit
 boost::optional< ::Ifc4x3_rc1::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > Ifc4x3_rc1::IfcProtectiveDeviceTrippingUnit::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcProtectiveDeviceTrippingUnitTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcProtectiveDeviceTrippingUnit::declaration() const { return *IFC4X3_RC1_IfcProtectiveDeviceTrippingUnit_type; }
@@ -19481,7 +19481,7 @@ Ifc4x3_rc1::IfcProtectiveDeviceType::IfcProtectiveDeviceType(std::string v1_Glob
 ::Ifc4x3_rc1::IfcObjectTypeEnum::Value Ifc4x3_rc1::IfcProxy::ProxyType() const {  return ::Ifc4x3_rc1::IfcObjectTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc1::IfcProxy::setProxyType(::Ifc4x3_rc1::IfcObjectTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcObjectTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcProxy::Tag() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcProxy::declaration() const { return *IFC4X3_RC1_IfcProxy_type; }
@@ -19491,7 +19491,7 @@ Ifc4x3_rc1::IfcProxy::IfcProxy(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHi
 
 // Function implementations for IfcPump
 boost::optional< ::Ifc4x3_rc1::IfcPumpTypeEnum::Value > Ifc4x3_rc1::IfcPump::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcPumpTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcPump::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPumpTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcPump::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcPumpTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcPump::declaration() const { return *IFC4X3_RC1_IfcPump_type; }
@@ -19513,7 +19513,7 @@ Ifc4x3_rc1::IfcPumpType::IfcPumpType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 double Ifc4x3_rc1::IfcQuantityArea::AreaValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcQuantityArea::setAreaValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcQuantityArea::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcQuantityArea::declaration() const { return *IFC4X3_RC1_IfcQuantityArea_type; }
@@ -19525,7 +19525,7 @@ Ifc4x3_rc1::IfcQuantityArea::IfcQuantityArea(std::string v1_Name, boost::optiona
 double Ifc4x3_rc1::IfcQuantityCount::CountValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcQuantityCount::setCountValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcQuantityCount::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcQuantityCount::declaration() const { return *IFC4X3_RC1_IfcQuantityCount_type; }
@@ -19537,7 +19537,7 @@ Ifc4x3_rc1::IfcQuantityCount::IfcQuantityCount(std::string v1_Name, boost::optio
 double Ifc4x3_rc1::IfcQuantityLength::LengthValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcQuantityLength::setLengthValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcQuantityLength::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcQuantityLength::declaration() const { return *IFC4X3_RC1_IfcQuantityLength_type; }
@@ -19557,7 +19557,7 @@ Ifc4x3_rc1::IfcQuantitySet::IfcQuantitySet(std::string v1_GlobalId, ::Ifc4x3_rc1
 double Ifc4x3_rc1::IfcQuantityTime::TimeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcQuantityTime::setTimeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcQuantityTime::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcQuantityTime::declaration() const { return *IFC4X3_RC1_IfcQuantityTime_type; }
@@ -19569,7 +19569,7 @@ Ifc4x3_rc1::IfcQuantityTime::IfcQuantityTime(std::string v1_Name, boost::optiona
 double Ifc4x3_rc1::IfcQuantityVolume::VolumeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcQuantityVolume::setVolumeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcQuantityVolume::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcQuantityVolume::declaration() const { return *IFC4X3_RC1_IfcQuantityVolume_type; }
@@ -19581,7 +19581,7 @@ Ifc4x3_rc1::IfcQuantityVolume::IfcQuantityVolume(std::string v1_Name, boost::opt
 double Ifc4x3_rc1::IfcQuantityWeight::WeightValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcQuantityWeight::setWeightValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcQuantityWeight::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcQuantityWeight::declaration() const { return *IFC4X3_RC1_IfcQuantityWeight_type; }
@@ -19591,7 +19591,7 @@ Ifc4x3_rc1::IfcQuantityWeight::IfcQuantityWeight(std::string v1_Name, boost::opt
 
 // Function implementations for IfcRail
 boost::optional< ::Ifc4x3_rc1::IfcRailTypeEnum::Value > Ifc4x3_rc1::IfcRail::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcRailTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcRail::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcRailTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcRailTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcRail::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcRailTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcRailTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRail::declaration() const { return *IFC4X3_RC1_IfcRail_type; }
@@ -19611,7 +19611,7 @@ Ifc4x3_rc1::IfcRailType::IfcRailType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcRailing
 boost::optional< ::Ifc4x3_rc1::IfcRailingTypeEnum::Value > Ifc4x3_rc1::IfcRailing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcRailingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcRailingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcRailingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRailing::declaration() const { return *IFC4X3_RC1_IfcRailing_type; }
@@ -19639,7 +19639,7 @@ Ifc4x3_rc1::IfcRailway::IfcRailway(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwn
 
 // Function implementations for IfcRamp
 boost::optional< ::Ifc4x3_rc1::IfcRampTypeEnum::Value > Ifc4x3_rc1::IfcRamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcRampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcRampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcRampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRamp::declaration() const { return *IFC4X3_RC1_IfcRamp_type; }
@@ -19649,7 +19649,7 @@ Ifc4x3_rc1::IfcRamp::IfcRamp(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHist
 
 // Function implementations for IfcRampFlight
 boost::optional< ::Ifc4x3_rc1::IfcRampFlightTypeEnum::Value > Ifc4x3_rc1::IfcRampFlight::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcRampFlightTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcRampFlightTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcRampFlightTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRampFlight::declaration() const { return *IFC4X3_RC1_IfcRampFlight_type; }
@@ -19701,9 +19701,9 @@ Ifc4x3_rc1::IfcRationalBSplineSurfaceWithKnots::IfcRationalBSplineSurfaceWithKno
 double Ifc4x3_rc1::IfcRectangleHollowProfileDef::WallThickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc1::IfcRectangleHollowProfileDef::setWallThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcRectangleHollowProfileDef::InnerFilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcRectangleHollowProfileDef::OuterFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRectangleHollowProfileDef::declaration() const { return *IFC4X3_RC1_IfcRectangleHollowProfileDef_type; }
@@ -19763,19 +19763,19 @@ Ifc4x3_rc1::IfcRectangularTrimmedSurface::IfcRectangularTrimmedSurface(::Ifc4x3_
 ::Ifc4x3_rc1::IfcRecurrenceTypeEnum::Value Ifc4x3_rc1::IfcRecurrencePattern::RecurrenceType() const {  return ::Ifc4x3_rc1::IfcRecurrenceTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc1::IfcRecurrencePattern::setRecurrenceType(::Ifc4x3_rc1::IfcRecurrenceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcRecurrenceTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc1::IfcRecurrencePattern::DayComponent() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc1::IfcRecurrencePattern::WeekdayComponent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc1::IfcRecurrencePattern::MonthComponent() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc1::IfcRecurrencePattern::Position() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< int > Ifc4x3_rc1::IfcRecurrencePattern::Interval() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } int v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x3_rc1::IfcRecurrencePattern::Occurrences() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcTimePeriod >::ptr > Ifc4x3_rc1::IfcRecurrencePattern::TimePeriods() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc1::IfcTimePeriod >(); }
-void Ifc4x3_rc1::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRecurrencePattern::declaration() const { return *IFC4X3_RC1_IfcRecurrencePattern_type; }
@@ -19785,13 +19785,13 @@ Ifc4x3_rc1::IfcRecurrencePattern::IfcRecurrencePattern(::Ifc4x3_rc1::IfcRecurren
 
 // Function implementations for IfcReference
 boost::optional< std::string > Ifc4x3_rc1::IfcReference::TypeIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcReference::AttributeIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcReference::InstanceName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc1::IfcReference::ListPositions() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc1::IfcReference* Ifc4x3_rc1::IfcReference::InnerReference() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc1::IfcReference>(true); }
 void Ifc4x3_rc1::IfcReference::setInnerReference(::Ifc4x3_rc1::IfcReference* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -19803,9 +19803,9 @@ Ifc4x3_rc1::IfcReference::IfcReference(boost::optional< std::string > v1_TypeIde
 
 // Function implementations for IfcReferent
 boost::optional< ::Ifc4x3_rc1::IfcReferentTypeEnum::Value > Ifc4x3_rc1::IfcReferent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcReferentTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc1::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReferentTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReferentTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReferent::RestartDistance() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcReferent::declaration() const { return *IFC4X3_RC1_IfcReferent_type; }
@@ -19827,7 +19827,7 @@ Ifc4x3_rc1::IfcRegularTimeSeries::IfcRegularTimeSeries(std::string v1_Name, boos
 
 // Function implementations for IfcReinforcedSoil
 boost::optional< ::Ifc4x3_rc1::IfcReinforcedSoilTypeEnum::Value > Ifc4x3_rc1::IfcReinforcedSoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcReinforcedSoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcReinforcedSoil::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcReinforcedSoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcedSoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcReinforcedSoil::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcReinforcedSoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcedSoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcReinforcedSoil::declaration() const { return *IFC4X3_RC1_IfcReinforcedSoil_type; }
@@ -19841,13 +19841,13 @@ void Ifc4x3_rc1::IfcReinforcementBarProperties::setTotalCrossSectionArea(double
 std::string Ifc4x3_rc1::IfcReinforcementBarProperties::SteelGrade() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcReinforcementBarProperties::setSteelGrade(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc1::IfcReinforcementBarProperties::BarSurface() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc1::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcementBarProperties::EffectiveDepth() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcementBarProperties::NominalBarDiameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcementBarProperties::BarCount() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcReinforcementBarProperties::declaration() const { return *IFC4X3_RC1_IfcReinforcementBarProperties_type; }
@@ -19857,7 +19857,7 @@ Ifc4x3_rc1::IfcReinforcementBarProperties::IfcReinforcementBarProperties(double
 
 // Function implementations for IfcReinforcementDefinitionProperties
 boost::optional< std::string > Ifc4x3_rc1::IfcReinforcementDefinitionProperties::DefinitionType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x3_rc1::IfcSectionReinforcementProperties >::ptr Ifc4x3_rc1::IfcReinforcementDefinitionProperties::ReinforcementSectionDefinitions() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc1::IfcSectionReinforcementProperties >(); }
 void Ifc4x3_rc1::IfcReinforcementDefinitionProperties::setReinforcementSectionDefinitions(aggregate_of< ::Ifc4x3_rc1::IfcSectionReinforcementProperties >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -19869,15 +19869,15 @@ Ifc4x3_rc1::IfcReinforcementDefinitionProperties::IfcReinforcementDefinitionProp
 
 // Function implementations for IfcReinforcingBar
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingBar::NominalDiameter() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingBar::CrossSectionArea() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingBar::BarLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarTypeEnum::Value > Ifc4x3_rc1::IfcReinforcingBar::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc1::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcingBarTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcingBarTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc1::IfcReinforcingBar::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc1::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcReinforcingBar::declaration() const { return *IFC4X3_RC1_IfcReinforcingBar_type; }
@@ -19889,17 +19889,17 @@ Ifc4x3_rc1::IfcReinforcingBar::IfcReinforcingBar(std::string v1_GlobalId, ::Ifc4
 ::Ifc4x3_rc1::IfcReinforcingBarTypeEnum::Value Ifc4x3_rc1::IfcReinforcingBarType::PredefinedType() const {  return ::Ifc4x3_rc1::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc1::IfcReinforcingBarType::setPredefinedType(::Ifc4x3_rc1::IfcReinforcingBarTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcReinforcingBarTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingBarType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingBarType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingBarType::BarLength() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc1::IfcReinforcingBarType::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc1::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcReinforcingBarType::BendingShapeCode() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc1::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc1::IfcReinforcingBarType::BendingParameters() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc1::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc1::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcReinforcingBarType::declaration() const { return *IFC4X3_RC1_IfcReinforcingBarType_type; }
@@ -19909,7 +19909,7 @@ Ifc4x3_rc1::IfcReinforcingBarType::IfcReinforcingBarType(std::string v1_GlobalId
 
 // Function implementations for IfcReinforcingElement
 boost::optional< std::string > Ifc4x3_rc1::IfcReinforcingElement::SteelGrade() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcReinforcingElement::declaration() const { return *IFC4X3_RC1_IfcReinforcingElement_type; }
@@ -19927,23 +19927,23 @@ Ifc4x3_rc1::IfcReinforcingElementType::IfcReinforcingElementType(std::string v1_
 
 // Function implementations for IfcReinforcingMesh
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMesh::MeshLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMesh::MeshWidth() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMesh::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMesh::TransverseBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMesh::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc1::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMesh::TransverseBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc1::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMesh::LongitudinalBarSpacing() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc1::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMesh::TransverseBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc1::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcReinforcingMeshTypeEnum::Value > Ifc4x3_rc1::IfcReinforcingMesh::PredefinedType() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(17)); }
-void Ifc4x3_rc1::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcingMeshTypeEnum::ToString(*v)));data_->setArgument(17,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcReinforcingMeshTypeEnum::ToString(*v)));}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcReinforcingMesh::declaration() const { return *IFC4X3_RC1_IfcReinforcingMesh_type; }
@@ -19955,25 +19955,25 @@ Ifc4x3_rc1::IfcReinforcingMesh::IfcReinforcingMesh(std::string v1_GlobalId, ::If
 ::Ifc4x3_rc1::IfcReinforcingMeshTypeEnum::Value Ifc4x3_rc1::IfcReinforcingMeshType::PredefinedType() const {  return ::Ifc4x3_rc1::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc1::IfcReinforcingMeshType::setPredefinedType(::Ifc4x3_rc1::IfcReinforcingMeshTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcReinforcingMeshTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMeshType::MeshLength() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMeshType::MeshWidth() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMeshType::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMeshType::TransverseBarNominalDiameter() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc1::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMeshType::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc1::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMeshType::TransverseBarCrossSectionArea() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc1::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMeshType::LongitudinalBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc1::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcReinforcingMeshType::TransverseBarSpacing() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc1::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcReinforcingMeshType::BendingShapeCode() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x3_rc1::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc1::IfcReinforcingMeshType::BendingParameters() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(19); return v; }
-void Ifc4x3_rc1::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x3_rc1::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcReinforcingMeshType::declaration() const { return *IFC4X3_RC1_IfcReinforcingMeshType_type; }
@@ -19997,7 +19997,7 @@ Ifc4x3_rc1::IfcRelAggregates::IfcRelAggregates(std::string v1_GlobalId, ::Ifc4x3
 aggregate_of< ::Ifc4x3_rc1::IfcObjectDefinition >::ptr Ifc4x3_rc1::IfcRelAssigns::RelatedObjects() const {  aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x3_rc1::IfcObjectDefinition >(); }
 void Ifc4x3_rc1::IfcRelAssigns::setRelatedObjects(aggregate_of< ::Ifc4x3_rc1::IfcObjectDefinition >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcObjectTypeEnum::Value > Ifc4x3_rc1::IfcRelAssigns::RelatedObjectsType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcObjectTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc1::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x3_rc1::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcObjectTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x3_rc1::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcObjectTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRelAssigns::declaration() const { return *IFC4X3_RC1_IfcRelAssigns_type; }
@@ -20111,7 +20111,7 @@ Ifc4x3_rc1::IfcRelAssociatesClassification::IfcRelAssociatesClassification(std::
 
 // Function implementations for IfcRelAssociatesConstraint
 boost::optional< std::string > Ifc4x3_rc1::IfcRelAssociatesConstraint::Intent() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc1::IfcConstraint* Ifc4x3_rc1::IfcRelAssociatesConstraint::RelatingConstraint() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcConstraint>(true); }
 void Ifc4x3_rc1::IfcRelAssociatesConstraint::setRelatingConstraint(::Ifc4x3_rc1::IfcConstraint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -20247,7 +20247,7 @@ void Ifc4x3_rc1::IfcRelConnectsStructuralMember::setAppliedCondition(::Ifc4x3_rc
 ::Ifc4x3_rc1::IfcStructuralConnectionCondition* Ifc4x3_rc1::IfcRelConnectsStructuralMember::AdditionalConditions() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc1::IfcStructuralConnectionCondition>(true); }
 void Ifc4x3_rc1::IfcRelConnectsStructuralMember::setAdditionalConditions(::Ifc4x3_rc1::IfcStructuralConnectionCondition* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcRelConnectsStructuralMember::SupportedLength() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc1::IfcAxis2Placement3D* Ifc4x3_rc1::IfcRelConnectsStructuralMember::ConditionCoordinateSystem() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc1::IfcAxis2Placement3D>(true); }
 void Ifc4x3_rc1::IfcRelConnectsStructuralMember::setConditionCoordinateSystem(::Ifc4x3_rc1::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -20271,7 +20271,7 @@ Ifc4x3_rc1::IfcRelConnectsWithEccentricity::IfcRelConnectsWithEccentricity(std::
 aggregate_of< ::Ifc4x3_rc1::IfcElement >::ptr Ifc4x3_rc1::IfcRelConnectsWithRealizingElements::RealizingElements() const {  aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc1::IfcElement >(); }
 void Ifc4x3_rc1::IfcRelConnectsWithRealizingElements::setRealizingElements(aggregate_of< ::Ifc4x3_rc1::IfcElement >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcRelConnectsWithRealizingElements::ConnectionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRelConnectsWithRealizingElements::declaration() const { return *IFC4X3_RC1_IfcRelConnectsWithRealizingElements_type; }
@@ -20423,7 +20423,7 @@ void Ifc4x3_rc1::IfcRelInterferesElements::setRelatedElement(::Ifc4x3_rc1::IfcIn
 ::Ifc4x3_rc1::IfcConnectionGeometry* Ifc4x3_rc1::IfcRelInterferesElements::InterferenceGeometry() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcConnectionGeometry>(true); }
 void Ifc4x3_rc1::IfcRelInterferesElements::setInterferenceGeometry(::Ifc4x3_rc1::IfcConnectionGeometry* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcRelInterferesElements::InterferenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::logic::tribool Ifc4x3_rc1::IfcRelInterferesElements::ImpliedOrder() const {  boost::logic::tribool v = *data_->getArgument(8); return v; }
 void Ifc4x3_rc1::IfcRelInterferesElements::setImpliedOrder(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -20489,9 +20489,9 @@ void Ifc4x3_rc1::IfcRelSequence::setRelatedProcess(::Ifc4x3_rc1::IfcProcess* v)
 ::Ifc4x3_rc1::IfcLagTime* Ifc4x3_rc1::IfcRelSequence::TimeLag() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcLagTime>(true); }
 void Ifc4x3_rc1::IfcRelSequence::setTimeLag(::Ifc4x3_rc1::IfcLagTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcSequenceEnum::Value > Ifc4x3_rc1::IfcRelSequence::SequenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSequenceEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc1::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x3_rc1::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSequenceEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x3_rc1::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSequenceEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcRelSequence::UserDefinedSequenceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRelSequence::declaration() const { return *IFC4X3_RC1_IfcRelSequence_type; }
@@ -20585,9 +20585,9 @@ Ifc4x3_rc1::IfcReparametrisedCompositeCurveSegment::IfcReparametrisedCompositeCu
 ::Ifc4x3_rc1::IfcRepresentationContext* Ifc4x3_rc1::IfcRepresentation::ContextOfItems() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc1::IfcRepresentationContext>(true); }
 void Ifc4x3_rc1::IfcRepresentation::setContextOfItems(::Ifc4x3_rc1::IfcRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcRepresentation::RepresentationIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcRepresentation::RepresentationType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc4x3_rc1::IfcRepresentationItem >::ptr Ifc4x3_rc1::IfcRepresentation::Items() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc1::IfcRepresentationItem >(); }
 void Ifc4x3_rc1::IfcRepresentation::setItems(aggregate_of< ::Ifc4x3_rc1::IfcRepresentationItem >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 
@@ -20602,9 +20602,9 @@ Ifc4x3_rc1::IfcRepresentation::IfcRepresentation(::Ifc4x3_rc1::IfcRepresentation
 
 // Function implementations for IfcRepresentationContext
 boost::optional< std::string > Ifc4x3_rc1::IfcRepresentationContext::ContextIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcRepresentationContext::ContextType() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc1::IfcRepresentation::list::ptr Ifc4x3_rc1::IfcRepresentationContext::RepresentationsInContext() const { return data_->getInverse(IFC4X3_RC1_IfcRepresentation_type, 0)->as<IfcRepresentation>(); }
 
@@ -20639,9 +20639,9 @@ Ifc4x3_rc1::IfcRepresentationMap::IfcRepresentationMap(::Ifc4x3_rc1::IfcAxis2Pla
 
 // Function implementations for IfcResource
 boost::optional< std::string > Ifc4x3_rc1::IfcResource::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResource::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc1::IfcRelAssignsToResource::list::ptr Ifc4x3_rc1::IfcResource::ResourceOf() const { return data_->getInverse(IFC4X3_RC1_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -20676,9 +20676,9 @@ Ifc4x3_rc1::IfcResourceConstraintRelationship::IfcResourceConstraintRelationship
 
 // Function implementations for IfcResourceLevelRelationship
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceLevelRelationship::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceLevelRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcResourceLevelRelationship::declaration() const { return *IFC4X3_RC1_IfcResourceLevelRelationship_type; }
@@ -20688,35 +20688,35 @@ Ifc4x3_rc1::IfcResourceLevelRelationship::IfcResourceLevelRelationship(boost::op
 
 // Function implementations for IfcResourceTime
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceTime::ScheduleWork() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcResourceTime::ScheduleUsage() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceTime::ScheduleContour() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceTime::LevelingDelay() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcResourceTime::IsOverAllocated() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceTime::StatusTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceTime::ActualWork() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcResourceTime::ActualUsage() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceTime::ActualStart() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceTime::ActualFinish() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcResourceTime::RemainingWork() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcResourceTime::RemainingUsage() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcResourceTime::Completion() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc1::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc1::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcResourceTime::declaration() const { return *IFC4X3_RC1_IfcResourceTime_type; }
@@ -20780,7 +20780,7 @@ Ifc4x3_rc1::IfcRoad::IfcRoad(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHist
 
 // Function implementations for IfcRoof
 boost::optional< ::Ifc4x3_rc1::IfcRoofTypeEnum::Value > Ifc4x3_rc1::IfcRoof::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcRoofTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcRoofTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcRoofTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRoof::declaration() const { return *IFC4X3_RC1_IfcRoof_type; }
@@ -20804,9 +20804,9 @@ void Ifc4x3_rc1::IfcRoot::setGlobalId(std::string v) { {IfcWrite::IfcWriteArgume
 ::Ifc4x3_rc1::IfcOwnerHistory* Ifc4x3_rc1::IfcRoot::OwnerHistory() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc1::IfcOwnerHistory>(true); }
 void Ifc4x3_rc1::IfcRoot::setOwnerHistory(::Ifc4x3_rc1::IfcOwnerHistory* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcRoot::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcRoot::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcRoot::declaration() const { return *IFC4X3_RC1_IfcRoot_type; }
@@ -20826,7 +20826,7 @@ Ifc4x3_rc1::IfcRoundedRectangleProfileDef::IfcRoundedRectangleProfileDef(::Ifc4x
 
 // Function implementations for IfcSIUnit
 boost::optional< ::Ifc4x3_rc1::IfcSIPrefix::Value > Ifc4x3_rc1::IfcSIUnit::Prefix() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSIPrefix::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc1::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x3_rc1::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSIPrefix::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x3_rc1::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSIPrefix::ToString(*v)));}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcSIUnitName::Value Ifc4x3_rc1::IfcSIUnit::Name() const {  return ::Ifc4x3_rc1::IfcSIUnitName::FromString(*data_->getArgument(3)); }
 void Ifc4x3_rc1::IfcSIUnit::setName(::Ifc4x3_rc1::IfcSIUnitName::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcSIUnitName::ToString(v)));data_->setArgument(3,attr);} }
 
@@ -20838,7 +20838,7 @@ Ifc4x3_rc1::IfcSIUnit::IfcSIUnit(::Ifc4x3_rc1::IfcUnitEnum::Value v2_UnitType, b
 
 // Function implementations for IfcSanitaryTerminal
 boost::optional< ::Ifc4x3_rc1::IfcSanitaryTerminalTypeEnum::Value > Ifc4x3_rc1::IfcSanitaryTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSanitaryTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSanitaryTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSanitaryTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSanitaryTerminal::declaration() const { return *IFC4X3_RC1_IfcSanitaryTerminal_type; }
@@ -20858,11 +20858,11 @@ Ifc4x3_rc1::IfcSanitaryTerminalType::IfcSanitaryTerminalType(std::string v1_Glob
 
 // Function implementations for IfcSchedulingTime
 boost::optional< std::string > Ifc4x3_rc1::IfcSchedulingTime::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcDataOriginEnum::Value > Ifc4x3_rc1::IfcSchedulingTime::DataOrigin() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcDataOriginEnum::FromString(*data_->getArgument(1)); }
-void Ifc4x3_rc1::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x3_rc1::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDataOriginEnum::ToString(*v)));data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x3_rc1::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcDataOriginEnum::ToString(*v)));}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcSchedulingTime::UserDefinedDataOrigin() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSchedulingTime::declaration() const { return *IFC4X3_RC1_IfcSchedulingTime_type; }
@@ -20898,7 +20898,7 @@ void Ifc4x3_rc1::IfcSectionReinforcementProperties::setLongitudinalStartPosition
 double Ifc4x3_rc1::IfcSectionReinforcementProperties::LongitudinalEndPosition() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcSectionReinforcementProperties::setLongitudinalEndPosition(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSectionReinforcementProperties::TransversePosition() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcReinforcingBarRoleEnum::Value Ifc4x3_rc1::IfcSectionReinforcementProperties::ReinforcementRole() const {  return ::Ifc4x3_rc1::IfcReinforcingBarRoleEnum::FromString(*data_->getArgument(3)); }
 void Ifc4x3_rc1::IfcSectionReinforcementProperties::setReinforcementRole(::Ifc4x3_rc1::IfcReinforcingBarRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcReinforcingBarRoleEnum::ToString(v)));data_->setArgument(3,attr);} }
 ::Ifc4x3_rc1::IfcSectionProperties* Ifc4x3_rc1::IfcSectionReinforcementProperties::SectionDefinition() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc1::IfcSectionProperties>(true); }
@@ -20968,7 +20968,7 @@ Ifc4x3_rc1::IfcSectionedSurface::IfcSectionedSurface(::Ifc4x3_rc1::IfcCurve* v1_
 
 // Function implementations for IfcSensor
 boost::optional< ::Ifc4x3_rc1::IfcSensorTypeEnum::Value > Ifc4x3_rc1::IfcSensor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSensorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSensorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSensorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSensor::declaration() const { return *IFC4X3_RC1_IfcSensor_type; }
@@ -20988,7 +20988,7 @@ Ifc4x3_rc1::IfcSensorType::IfcSensorType(std::string v1_GlobalId, ::Ifc4x3_rc1::
 
 // Function implementations for IfcShadingDevice
 boost::optional< ::Ifc4x3_rc1::IfcShadingDeviceTypeEnum::Value > Ifc4x3_rc1::IfcShadingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcShadingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcShadingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcShadingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcShadingDevice::declaration() const { return *IFC4X3_RC1_IfcShadingDevice_type; }
@@ -21010,9 +21010,9 @@ Ifc4x3_rc1::IfcShadingDeviceType::IfcShadingDeviceType(std::string v1_GlobalId,
 aggregate_of< ::Ifc4x3_rc1::IfcShapeModel >::ptr Ifc4x3_rc1::IfcShapeAspect::ShapeRepresentations() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x3_rc1::IfcShapeModel >(); }
 void Ifc4x3_rc1::IfcShapeAspect::setShapeRepresentations(aggregate_of< ::Ifc4x3_rc1::IfcShapeModel >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcShapeAspect::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcShapeAspect::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::logic::tribool Ifc4x3_rc1::IfcShapeAspect::ProductDefinitional() const {  boost::logic::tribool v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcShapeAspect::setProductDefinitional(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc1::IfcProductRepresentationSelect* Ifc4x3_rc1::IfcShapeAspect::PartOfProductDefinitionShape() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc1::IfcProductRepresentationSelect>(true); }
@@ -21054,7 +21054,7 @@ Ifc4x3_rc1::IfcShellBasedSurfaceModel::IfcShellBasedSurfaceModel(aggregate_of_in
 
 // Function implementations for IfcSign
 boost::optional< ::Ifc4x3_rc1::IfcSignTypeEnum::Value > Ifc4x3_rc1::IfcSign::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSignTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSign::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSignTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSignTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSign::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSignTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSignTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSign::declaration() const { return *IFC4X3_RC1_IfcSign_type; }
@@ -21074,7 +21074,7 @@ Ifc4x3_rc1::IfcSignType::IfcSignType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcSignal
 boost::optional< ::Ifc4x3_rc1::IfcSignalTypeEnum::Value > Ifc4x3_rc1::IfcSignal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSignalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSignal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSignalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSignalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSignal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSignalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSignalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSignal::declaration() const { return *IFC4X3_RC1_IfcSignal_type; }
@@ -21102,11 +21102,11 @@ Ifc4x3_rc1::IfcSimpleProperty::IfcSimpleProperty(std::string v1_Name, boost::opt
 
 // Function implementations for IfcSimplePropertyTemplate
 boost::optional< ::Ifc4x3_rc1::IfcSimplePropertyTemplateTypeEnum::Value > Ifc4x3_rc1::IfcSimplePropertyTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSimplePropertyTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x3_rc1::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc1::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc1::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcSimplePropertyTemplate::PrimaryMeasureType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcSimplePropertyTemplate::SecondaryMeasureType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc1::IfcPropertyEnumeration* Ifc4x3_rc1::IfcSimplePropertyTemplate::Enumerators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc1::IfcPropertyEnumeration>(true); }
 void Ifc4x3_rc1::IfcSimplePropertyTemplate::setEnumerators(::Ifc4x3_rc1::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x3_rc1::IfcUnit* Ifc4x3_rc1::IfcSimplePropertyTemplate::PrimaryUnit() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc1::IfcUnit>(true); }
@@ -21114,9 +21114,9 @@ void Ifc4x3_rc1::IfcSimplePropertyTemplate::setPrimaryUnit(::Ifc4x3_rc1::IfcUnit
 ::Ifc4x3_rc1::IfcUnit* Ifc4x3_rc1::IfcSimplePropertyTemplate::SecondaryUnit() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc1::IfcUnit>(true); }
 void Ifc4x3_rc1::IfcSimplePropertyTemplate::setSecondaryUnit(::Ifc4x3_rc1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcSimplePropertyTemplate::Expression() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcStateEnum::Value > Ifc4x3_rc1::IfcSimplePropertyTemplate::AccessState() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcStateEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc1::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x3_rc1::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcStateEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x3_rc1::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcStateEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSimplePropertyTemplate::declaration() const { return *IFC4X3_RC1_IfcSimplePropertyTemplate_type; }
@@ -21126,13 +21126,13 @@ Ifc4x3_rc1::IfcSimplePropertyTemplate::IfcSimplePropertyTemplate(std::string v1_
 
 // Function implementations for IfcSite
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x3_rc1::IfcSite::RefLatitude() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x3_rc1::IfcSite::RefLongitude() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSite::RefElevation() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcSite::LandTitleNumber() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x3_rc1::IfcPostalAddress* Ifc4x3_rc1::IfcSite::SiteAddress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x3_rc1::IfcPostalAddress>(true); }
 void Ifc4x3_rc1::IfcSite::setSiteAddress(::Ifc4x3_rc1::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -21144,7 +21144,7 @@ Ifc4x3_rc1::IfcSite::IfcSite(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHist
 
 // Function implementations for IfcSlab
 boost::optional< ::Ifc4x3_rc1::IfcSlabTypeEnum::Value > Ifc4x3_rc1::IfcSlab::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSlabTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSlabTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSlabTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSlab::declaration() const { return *IFC4X3_RC1_IfcSlab_type; }
@@ -21180,11 +21180,11 @@ Ifc4x3_rc1::IfcSlabType::IfcSlabType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcSlippageConnectionCondition
 boost::optional< double > Ifc4x3_rc1::IfcSlippageConnectionCondition::SlippageX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSlippageConnectionCondition::SlippageY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSlippageConnectionCondition::SlippageZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSlippageConnectionCondition::declaration() const { return *IFC4X3_RC1_IfcSlippageConnectionCondition_type; }
@@ -21194,7 +21194,7 @@ Ifc4x3_rc1::IfcSlippageConnectionCondition::IfcSlippageConnectionCondition(boost
 
 // Function implementations for IfcSolarDevice
 boost::optional< ::Ifc4x3_rc1::IfcSolarDeviceTypeEnum::Value > Ifc4x3_rc1::IfcSolarDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSolarDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSolarDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSolarDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSolarDevice::declaration() const { return *IFC4X3_RC1_IfcSolarDevice_type; }
@@ -21230,9 +21230,9 @@ Ifc4x3_rc1::IfcSolidStratum::IfcSolidStratum(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcSpace
 boost::optional< ::Ifc4x3_rc1::IfcSpaceTypeEnum::Value > Ifc4x3_rc1::IfcSpace::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc1::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSpaceTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSpaceTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSpace::ElevationWithFlooring() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 ::Ifc4x3_rc1::IfcRelCoversSpaces::list::ptr Ifc4x3_rc1::IfcSpace::HasCoverings() const { return data_->getInverse(IFC4X3_RC1_IfcRelCoversSpaces_type, 4)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x3_rc1::IfcRelSpaceBoundary::list::ptr Ifc4x3_rc1::IfcSpace::BoundedBy() const { return data_->getInverse(IFC4X3_RC1_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
@@ -21244,7 +21244,7 @@ Ifc4x3_rc1::IfcSpace::IfcSpace(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHi
 
 // Function implementations for IfcSpaceHeater
 boost::optional< ::Ifc4x3_rc1::IfcSpaceHeaterTypeEnum::Value > Ifc4x3_rc1::IfcSpaceHeater::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSpaceHeaterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSpaceHeaterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSpaceHeaterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSpaceHeater::declaration() const { return *IFC4X3_RC1_IfcSpaceHeater_type; }
@@ -21266,7 +21266,7 @@ Ifc4x3_rc1::IfcSpaceHeaterType::IfcSpaceHeaterType(std::string v1_GlobalId, ::If
 ::Ifc4x3_rc1::IfcSpaceTypeEnum::Value Ifc4x3_rc1::IfcSpaceType::PredefinedType() const {  return ::Ifc4x3_rc1::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc1::IfcSpaceType::setPredefinedType(::Ifc4x3_rc1::IfcSpaceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcSpaceTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcSpaceType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSpaceType::declaration() const { return *IFC4X3_RC1_IfcSpaceType_type; }
@@ -21276,7 +21276,7 @@ Ifc4x3_rc1::IfcSpaceType::IfcSpaceType(std::string v1_GlobalId, ::Ifc4x3_rc1::If
 
 // Function implementations for IfcSpatialElement
 boost::optional< std::string > Ifc4x3_rc1::IfcSpatialElement::LongName() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc1::IfcRelContainedInSpatialStructure::list::ptr Ifc4x3_rc1::IfcSpatialElement::ContainsElements() const { return data_->getInverse(IFC4X3_RC1_IfcRelContainedInSpatialStructure_type, 5)->as<IfcRelContainedInSpatialStructure>(); }
 ::Ifc4x3_rc1::IfcRelServicesBuildings::list::ptr Ifc4x3_rc1::IfcSpatialElement::ServicedBySystems() const { return data_->getInverse(IFC4X3_RC1_IfcRelServicesBuildings_type, 5)->as<IfcRelServicesBuildings>(); }
@@ -21289,7 +21289,7 @@ Ifc4x3_rc1::IfcSpatialElement::IfcSpatialElement(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcSpatialElementType
 boost::optional< std::string > Ifc4x3_rc1::IfcSpatialElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSpatialElementType::declaration() const { return *IFC4X3_RC1_IfcSpatialElementType_type; }
@@ -21299,7 +21299,7 @@ Ifc4x3_rc1::IfcSpatialElementType::IfcSpatialElementType(std::string v1_GlobalId
 
 // Function implementations for IfcSpatialStructureElement
 boost::optional< ::Ifc4x3_rc1::IfcElementCompositionEnum::Value > Ifc4x3_rc1::IfcSpatialStructureElement::CompositionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcElementCompositionEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x3_rc1::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElementCompositionEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x3_rc1::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcElementCompositionEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSpatialStructureElement::declaration() const { return *IFC4X3_RC1_IfcSpatialStructureElement_type; }
@@ -21317,7 +21317,7 @@ Ifc4x3_rc1::IfcSpatialStructureElementType::IfcSpatialStructureElementType(std::
 
 // Function implementations for IfcSpatialZone
 boost::optional< ::Ifc4x3_rc1::IfcSpatialZoneTypeEnum::Value > Ifc4x3_rc1::IfcSpatialZone::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSpatialZoneTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSpatialZoneTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSpatialZone::declaration() const { return *IFC4X3_RC1_IfcSpatialZone_type; }
@@ -21329,7 +21329,7 @@ Ifc4x3_rc1::IfcSpatialZone::IfcSpatialZone(std::string v1_GlobalId, ::Ifc4x3_rc1
 ::Ifc4x3_rc1::IfcSpatialZoneTypeEnum::Value Ifc4x3_rc1::IfcSpatialZoneType::PredefinedType() const {  return ::Ifc4x3_rc1::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc1::IfcSpatialZoneType::setPredefinedType(::Ifc4x3_rc1::IfcSpatialZoneTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcSpatialZoneTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcSpatialZoneType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSpatialZoneType::declaration() const { return *IFC4X3_RC1_IfcSpatialZoneType_type; }
@@ -21359,7 +21359,7 @@ Ifc4x3_rc1::IfcSphericalSurface::IfcSphericalSurface(::Ifc4x3_rc1::IfcAxis2Place
 
 // Function implementations for IfcStackTerminal
 boost::optional< ::Ifc4x3_rc1::IfcStackTerminalTypeEnum::Value > Ifc4x3_rc1::IfcStackTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcStackTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcStackTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcStackTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStackTerminal::declaration() const { return *IFC4X3_RC1_IfcStackTerminal_type; }
@@ -21379,7 +21379,7 @@ Ifc4x3_rc1::IfcStackTerminalType::IfcStackTerminalType(std::string v1_GlobalId,
 
 // Function implementations for IfcStair
 boost::optional< ::Ifc4x3_rc1::IfcStairTypeEnum::Value > Ifc4x3_rc1::IfcStair::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcStairTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcStair::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcStairTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcStair::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcStairTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStair::declaration() const { return *IFC4X3_RC1_IfcStair_type; }
@@ -21389,15 +21389,15 @@ Ifc4x3_rc1::IfcStair::IfcStair(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHi
 
 // Function implementations for IfcStairFlight
 boost::optional< int > Ifc4x3_rc1::IfcStairFlight::NumberOfRisers() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } int v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< int > Ifc4x3_rc1::IfcStairFlight::NumberOfTreads() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } int v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStairFlight::RiserHeight() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStairFlight::TreadLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcStairFlightTypeEnum::Value > Ifc4x3_rc1::IfcStairFlight::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcStairFlightTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc1::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcStairFlightTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcStairFlightTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStairFlight::declaration() const { return *IFC4X3_RC1_IfcStairFlight_type; }
@@ -21427,7 +21427,7 @@ Ifc4x3_rc1::IfcStairType::IfcStairType(std::string v1_GlobalId, ::Ifc4x3_rc1::If
 
 // Function implementations for IfcStructuralAction
 boost::optional< bool > Ifc4x3_rc1::IfcStructuralAction::DestabilizingLoad() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralAction::declaration() const { return *IFC4X3_RC1_IfcStructuralAction_type; }
@@ -21454,9 +21454,9 @@ void Ifc4x3_rc1::IfcStructuralAnalysisModel::setPredefinedType(::Ifc4x3_rc1::Ifc
 ::Ifc4x3_rc1::IfcAxis2Placement3D* Ifc4x3_rc1::IfcStructuralAnalysisModel::OrientationOf2DPlane() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcAxis2Placement3D>(true); }
 void Ifc4x3_rc1::IfcStructuralAnalysisModel::setOrientationOf2DPlane(::Ifc4x3_rc1::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcStructuralLoadGroup >::ptr > Ifc4x3_rc1::IfcStructuralAnalysisModel::LoadedBy() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc1::IfcStructuralLoadGroup >(); }
-void Ifc4x3_rc1::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcStructuralResultGroup >::ptr > Ifc4x3_rc1::IfcStructuralAnalysisModel::HasResults() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc1::IfcStructuralResultGroup >(); }
-void Ifc4x3_rc1::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc1::IfcObjectPlacement* Ifc4x3_rc1::IfcStructuralAnalysisModel::SharedPlacement() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc1::IfcObjectPlacement>(true); }
 void Ifc4x3_rc1::IfcStructuralAnalysisModel::setSharedPlacement(::Ifc4x3_rc1::IfcObjectPlacement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -21479,7 +21479,7 @@ Ifc4x3_rc1::IfcStructuralConnection::IfcStructuralConnection(std::string v1_Glob
 
 // Function implementations for IfcStructuralConnectionCondition
 boost::optional< std::string > Ifc4x3_rc1::IfcStructuralConnectionCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralConnectionCondition::declaration() const { return *IFC4X3_RC1_IfcStructuralConnectionCondition_type; }
@@ -21489,7 +21489,7 @@ Ifc4x3_rc1::IfcStructuralConnectionCondition::IfcStructuralConnectionCondition(b
 
 // Function implementations for IfcStructuralCurveAction
 boost::optional< ::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::Value > Ifc4x3_rc1::IfcStructuralCurveAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc1::IfcStructuralCurveActivityTypeEnum::Value Ifc4x3_rc1::IfcStructuralCurveAction::PredefinedType() const {  return ::Ifc4x3_rc1::IfcStructuralCurveActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x3_rc1::IfcStructuralCurveAction::setPredefinedType(::Ifc4x3_rc1::IfcStructuralCurveActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcStructuralCurveActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -21558,7 +21558,7 @@ Ifc4x3_rc1::IfcStructuralLinearAction::IfcStructuralLinearAction(std::string v1_
 
 // Function implementations for IfcStructuralLoad
 boost::optional< std::string > Ifc4x3_rc1::IfcStructuralLoad::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralLoad::declaration() const { return *IFC4X3_RC1_IfcStructuralLoad_type; }
@@ -21568,7 +21568,7 @@ Ifc4x3_rc1::IfcStructuralLoad::IfcStructuralLoad(boost::optional< std::string >
 
 // Function implementations for IfcStructuralLoadCase
 boost::optional< std::vector< double > /*[3:3]*/ > Ifc4x3_rc1::IfcStructuralLoadCase::SelfWeightCoefficients() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< double > /*[3:3]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralLoadCase::declaration() const { return *IFC4X3_RC1_IfcStructuralLoadCase_type; }
@@ -21580,7 +21580,7 @@ Ifc4x3_rc1::IfcStructuralLoadCase::IfcStructuralLoadCase(std::string v1_GlobalId
 aggregate_of< ::Ifc4x3_rc1::IfcStructuralLoadOrResult >::ptr Ifc4x3_rc1::IfcStructuralLoadConfiguration::Values() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc1::IfcStructuralLoadOrResult >(); }
 void Ifc4x3_rc1::IfcStructuralLoadConfiguration::setValues(aggregate_of< ::Ifc4x3_rc1::IfcStructuralLoadOrResult >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::vector< std::vector< double > > > Ifc4x3_rc1::IfcStructuralLoadConfiguration::Locations() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralLoadConfiguration::declaration() const { return *IFC4X3_RC1_IfcStructuralLoadConfiguration_type; }
@@ -21596,9 +21596,9 @@ void Ifc4x3_rc1::IfcStructuralLoadGroup::setActionType(::Ifc4x3_rc1::IfcActionTy
 ::Ifc4x3_rc1::IfcActionSourceTypeEnum::Value Ifc4x3_rc1::IfcStructuralLoadGroup::ActionSource() const {  return ::Ifc4x3_rc1::IfcActionSourceTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc1::IfcStructuralLoadGroup::setActionSource(::Ifc4x3_rc1::IfcActionSourceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcActionSourceTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadGroup::Coefficient() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcStructuralLoadGroup::Purpose() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 ::Ifc4x3_rc1::IfcStructuralResultGroup::list::ptr Ifc4x3_rc1::IfcStructuralLoadGroup::SourceOfResultGroup() const { return data_->getInverse(IFC4X3_RC1_IfcStructuralResultGroup_type, 6)->as<IfcStructuralResultGroup>(); }
 ::Ifc4x3_rc1::IfcStructuralAnalysisModel::list::ptr Ifc4x3_rc1::IfcStructuralLoadGroup::LoadGroupFor() const { return data_->getInverse(IFC4X3_RC1_IfcStructuralAnalysisModel_type, 7)->as<IfcStructuralAnalysisModel>(); }
@@ -21610,17 +21610,17 @@ Ifc4x3_rc1::IfcStructuralLoadGroup::IfcStructuralLoadGroup(std::string v1_Global
 
 // Function implementations for IfcStructuralLoadLinearForce
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadLinearForce::LinearForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadLinearForce::LinearForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadLinearForce::LinearForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadLinearForce::LinearMomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadLinearForce::LinearMomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadLinearForce::LinearMomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralLoadLinearForce::declaration() const { return *IFC4X3_RC1_IfcStructuralLoadLinearForce_type; }
@@ -21638,11 +21638,11 @@ Ifc4x3_rc1::IfcStructuralLoadOrResult::IfcStructuralLoadOrResult(boost::optional
 
 // Function implementations for IfcStructuralLoadPlanarForce
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadPlanarForce::PlanarForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadPlanarForce::PlanarForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadPlanarForce::PlanarForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralLoadPlanarForce::declaration() const { return *IFC4X3_RC1_IfcStructuralLoadPlanarForce_type; }
@@ -21652,17 +21652,17 @@ Ifc4x3_rc1::IfcStructuralLoadPlanarForce::IfcStructuralLoadPlanarForce(boost::op
 
 // Function implementations for IfcStructuralLoadSingleDisplacement
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::DisplacementX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::DisplacementY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::DisplacementZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::declaration() const { return *IFC4X3_RC1_IfcStructuralLoadSingleDisplacement_type; }
@@ -21672,7 +21672,7 @@ Ifc4x3_rc1::IfcStructuralLoadSingleDisplacement::IfcStructuralLoadSingleDisplace
 
 // Function implementations for IfcStructuralLoadSingleDisplacementDistortion
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleDisplacementDistortion::Distortion() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralLoadSingleDisplacementDistortion::declaration() const { return *IFC4X3_RC1_IfcStructuralLoadSingleDisplacementDistortion_type; }
@@ -21682,17 +21682,17 @@ Ifc4x3_rc1::IfcStructuralLoadSingleDisplacementDistortion::IfcStructuralLoadSing
 
 // Function implementations for IfcStructuralLoadSingleForce
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleForce::ForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleForce::ForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleForce::ForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleForce::MomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleForce::MomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleForce::MomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralLoadSingleForce::declaration() const { return *IFC4X3_RC1_IfcStructuralLoadSingleForce_type; }
@@ -21702,7 +21702,7 @@ Ifc4x3_rc1::IfcStructuralLoadSingleForce::IfcStructuralLoadSingleForce(boost::op
 
 // Function implementations for IfcStructuralLoadSingleForceWarping
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadSingleForceWarping::WarpingMoment() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralLoadSingleForceWarping::declaration() const { return *IFC4X3_RC1_IfcStructuralLoadSingleForceWarping_type; }
@@ -21720,11 +21720,11 @@ Ifc4x3_rc1::IfcStructuralLoadStatic::IfcStructuralLoadStatic(boost::optional< st
 
 // Function implementations for IfcStructuralLoadTemperature
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadTemperature::DeltaTConstant() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadTemperature::DeltaTY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralLoadTemperature::DeltaTZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralLoadTemperature::declaration() const { return *IFC4X3_RC1_IfcStructuralLoadTemperature_type; }
@@ -21800,7 +21800,7 @@ Ifc4x3_rc1::IfcStructuralResultGroup::IfcStructuralResultGroup(std::string v1_Gl
 
 // Function implementations for IfcStructuralSurfaceAction
 boost::optional< ::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::Value > Ifc4x3_rc1::IfcStructuralSurfaceAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc1::IfcStructuralSurfaceActivityTypeEnum::Value Ifc4x3_rc1::IfcStructuralSurfaceAction::PredefinedType() const {  return ::Ifc4x3_rc1::IfcStructuralSurfaceActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x3_rc1::IfcStructuralSurfaceAction::setPredefinedType(::Ifc4x3_rc1::IfcStructuralSurfaceActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcStructuralSurfaceActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -21822,7 +21822,7 @@ Ifc4x3_rc1::IfcStructuralSurfaceConnection::IfcStructuralSurfaceConnection(std::
 ::Ifc4x3_rc1::IfcStructuralSurfaceMemberTypeEnum::Value Ifc4x3_rc1::IfcStructuralSurfaceMember::PredefinedType() const {  return ::Ifc4x3_rc1::IfcStructuralSurfaceMemberTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc1::IfcStructuralSurfaceMember::setPredefinedType(::Ifc4x3_rc1::IfcStructuralSurfaceMemberTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcStructuralSurfaceMemberTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcStructuralSurfaceMember::Thickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStructuralSurfaceMember::declaration() const { return *IFC4X3_RC1_IfcStructuralSurfaceMember_type; }
@@ -21862,7 +21862,7 @@ void Ifc4x3_rc1::IfcStyledItem::setItem(::Ifc4x3_rc1::IfcRepresentationItem* v)
 aggregate_of_instance::ptr Ifc4x3_rc1::IfcStyledItem::Styles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcStyledItem::setStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcStyledItem::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcStyledItem::declaration() const { return *IFC4X3_RC1_IfcStyledItem_type; }
@@ -21880,7 +21880,7 @@ Ifc4x3_rc1::IfcStyledRepresentation::IfcStyledRepresentation(::Ifc4x3_rc1::IfcRe
 
 // Function implementations for IfcSubContractResource
 boost::optional< ::Ifc4x3_rc1::IfcSubContractResourceTypeEnum::Value > Ifc4x3_rc1::IfcSubContractResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSubContractResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSubContractResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSubContractResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSubContractResource::declaration() const { return *IFC4X3_RC1_IfcSubContractResource_type; }
@@ -21942,7 +21942,7 @@ Ifc4x3_rc1::IfcSurfaceCurveSweptAreaSolid::IfcSurfaceCurveSweptAreaSolid(::Ifc4x
 
 // Function implementations for IfcSurfaceFeature
 boost::optional< ::Ifc4x3_rc1::IfcSurfaceFeatureTypeEnum::Value > Ifc4x3_rc1::IfcSurfaceFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSurfaceFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSurfaceFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSurfaceFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSurfaceFeature::declaration() const { return *IFC4X3_RC1_IfcSurfaceFeature_type; }
@@ -21974,11 +21974,11 @@ Ifc4x3_rc1::IfcSurfaceOfRevolution::IfcSurfaceOfRevolution(::Ifc4x3_rc1::IfcProf
 
 // Function implementations for IfcSurfaceReinforcementArea
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x3_rc1::IfcSurfaceReinforcementArea::SurfaceReinforcement1() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x3_rc1::IfcSurfaceReinforcementArea::SurfaceReinforcement2() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSurfaceReinforcementArea::ShearReinforcement() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSurfaceReinforcementArea::declaration() const { return *IFC4X3_RC1_IfcSurfaceReinforcementArea_type; }
@@ -22016,9 +22016,9 @@ Ifc4x3_rc1::IfcSurfaceStyleLighting::IfcSurfaceStyleLighting(::Ifc4x3_rc1::IfcCo
 
 // Function implementations for IfcSurfaceStyleRefraction
 boost::optional< double > Ifc4x3_rc1::IfcSurfaceStyleRefraction::RefractionIndex() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSurfaceStyleRefraction::DispersionFactor() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSurfaceStyleRefraction::declaration() const { return *IFC4X3_RC1_IfcSurfaceStyleRefraction_type; }
@@ -22052,7 +22052,7 @@ Ifc4x3_rc1::IfcSurfaceStyleRendering::IfcSurfaceStyleRendering(::Ifc4x3_rc1::Ifc
 ::Ifc4x3_rc1::IfcColourRgb* Ifc4x3_rc1::IfcSurfaceStyleShading::SurfaceColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc1::IfcColourRgb>(true); }
 void Ifc4x3_rc1::IfcSurfaceStyleShading::setSurfaceColour(::Ifc4x3_rc1::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSurfaceStyleShading::Transparency() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSurfaceStyleShading::declaration() const { return *IFC4X3_RC1_IfcSurfaceStyleShading_type; }
@@ -22076,11 +22076,11 @@ void Ifc4x3_rc1::IfcSurfaceTexture::setRepeatS(bool v) { {IfcWrite::IfcWriteArgu
 bool Ifc4x3_rc1::IfcSurfaceTexture::RepeatT() const {  bool v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcSurfaceTexture::setRepeatT(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcSurfaceTexture::Mode() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcCartesianTransformationOperator2D* Ifc4x3_rc1::IfcSurfaceTexture::TextureTransform() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x3_rc1::IfcSurfaceTexture::setTextureTransform(::Ifc4x3_rc1::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcSurfaceTexture::Parameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc1::IfcTextureCoordinate::list::ptr Ifc4x3_rc1::IfcSurfaceTexture::IsMappedBy() const { return data_->getInverse(IFC4X3_RC1_IfcTextureCoordinate_type, 0)->as<IfcTextureCoordinate>(); }
 ::Ifc4x3_rc1::IfcSurfaceStyleWithTextures::list::ptr Ifc4x3_rc1::IfcSurfaceTexture::UsedInStyles() const { return data_->getInverse(IFC4X3_RC1_IfcSurfaceStyleWithTextures_type, 0)->as<IfcSurfaceStyleWithTextures>(); }
@@ -22108,11 +22108,11 @@ void Ifc4x3_rc1::IfcSweptDiskSolid::setDirectrix(::Ifc4x3_rc1::IfcCurve* v) { {I
 double Ifc4x3_rc1::IfcSweptDiskSolid::Radius() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcSweptDiskSolid::setRadius(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSweptDiskSolid::InnerRadius() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSweptDiskSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcSweptDiskSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSweptDiskSolid::declaration() const { return *IFC4X3_RC1_IfcSweptDiskSolid_type; }
@@ -22122,7 +22122,7 @@ Ifc4x3_rc1::IfcSweptDiskSolid::IfcSweptDiskSolid(::Ifc4x3_rc1::IfcCurve* v1_Dire
 
 // Function implementations for IfcSweptDiskSolidPolygonal
 boost::optional< double > Ifc4x3_rc1::IfcSweptDiskSolidPolygonal::FilletRadius() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSweptDiskSolidPolygonal::declaration() const { return *IFC4X3_RC1_IfcSweptDiskSolidPolygonal_type; }
@@ -22144,7 +22144,7 @@ Ifc4x3_rc1::IfcSweptSurface::IfcSweptSurface(::Ifc4x3_rc1::IfcProfileDef* v1_Swe
 
 // Function implementations for IfcSwitchingDevice
 boost::optional< ::Ifc4x3_rc1::IfcSwitchingDeviceTypeEnum::Value > Ifc4x3_rc1::IfcSwitchingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSwitchingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSwitchingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSwitchingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSwitchingDevice::declaration() const { return *IFC4X3_RC1_IfcSwitchingDevice_type; }
@@ -22174,7 +22174,7 @@ Ifc4x3_rc1::IfcSystem::IfcSystem(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwner
 
 // Function implementations for IfcSystemFurnitureElement
 boost::optional< ::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x3_rc1::IfcSystemFurnitureElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSystemFurnitureElement::declaration() const { return *IFC4X3_RC1_IfcSystemFurnitureElement_type; }
@@ -22184,7 +22184,7 @@ Ifc4x3_rc1::IfcSystemFurnitureElement::IfcSystemFurnitureElement(std::string v1_
 
 // Function implementations for IfcSystemFurnitureElementType
 boost::optional< ::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x3_rc1::IfcSystemFurnitureElementType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc1::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcSystemFurnitureElementType::declaration() const { return *IFC4X3_RC1_IfcSystemFurnitureElementType_type; }
@@ -22202,15 +22202,15 @@ void Ifc4x3_rc1::IfcTShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc1::IfcTShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc1::IfcTShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTShapeProfileDef::WebEdgeRadius() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTShapeProfileDef::WebSlope() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTShapeProfileDef::declaration() const { return *IFC4X3_RC1_IfcTShapeProfileDef_type; }
@@ -22220,11 +22220,11 @@ Ifc4x3_rc1::IfcTShapeProfileDef::IfcTShapeProfileDef(::Ifc4x3_rc1::IfcProfileTyp
 
 // Function implementations for IfcTable
 boost::optional< std::string > Ifc4x3_rc1::IfcTable::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcTableRow >::ptr > Ifc4x3_rc1::IfcTable::Rows() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc1::IfcTableRow >(); }
-void Ifc4x3_rc1::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcTableColumn >::ptr > Ifc4x3_rc1::IfcTable::Columns() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc1::IfcTableColumn >(); }
-void Ifc4x3_rc1::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTable::declaration() const { return *IFC4X3_RC1_IfcTable_type; }
@@ -22234,11 +22234,11 @@ Ifc4x3_rc1::IfcTable::IfcTable(boost::optional< std::string > v1_Name, boost::op
 
 // Function implementations for IfcTableColumn
 boost::optional< std::string > Ifc4x3_rc1::IfcTableColumn::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTableColumn::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTableColumn::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcUnit* Ifc4x3_rc1::IfcTableColumn::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcUnit>(true); }
 void Ifc4x3_rc1::IfcTableColumn::setUnit(::Ifc4x3_rc1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc1::IfcReference* Ifc4x3_rc1::IfcTableColumn::ReferencePath() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc1::IfcReference>(true); }
@@ -22252,9 +22252,9 @@ Ifc4x3_rc1::IfcTableColumn::IfcTableColumn(boost::optional< std::string > v1_Ide
 
 // Function implementations for IfcTableRow
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc1::IfcTableRow::RowCells() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc1::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc1::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcTableRow::IsHeading() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTableRow::declaration() const { return *IFC4X3_RC1_IfcTableRow_type; }
@@ -22264,7 +22264,7 @@ Ifc4x3_rc1::IfcTableRow::IfcTableRow(boost::optional< aggregate_of_instance::ptr
 
 // Function implementations for IfcTank
 boost::optional< ::Ifc4x3_rc1::IfcTankTypeEnum::Value > Ifc4x3_rc1::IfcTank::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcTankTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcTank::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTankTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcTank::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTankTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTank::declaration() const { return *IFC4X3_RC1_IfcTank_type; }
@@ -22284,17 +22284,17 @@ Ifc4x3_rc1::IfcTankType::IfcTankType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcTask
 boost::optional< std::string > Ifc4x3_rc1::IfcTask::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTask::WorkMethod() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 bool Ifc4x3_rc1::IfcTask::IsMilestone() const {  bool v = *data_->getArgument(9); return v; }
 void Ifc4x3_rc1::IfcTask::setIsMilestone(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< int > Ifc4x3_rc1::IfcTask::Priority() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } int v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc1::IfcTaskTime* Ifc4x3_rc1::IfcTask::TaskTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc1::IfcTaskTime>(true); }
 void Ifc4x3_rc1::IfcTask::setTaskTime(::Ifc4x3_rc1::IfcTaskTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcTaskTypeEnum::Value > Ifc4x3_rc1::IfcTask::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcTaskTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc1::IfcTask::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTaskTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcTask::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTaskTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTask::declaration() const { return *IFC4X3_RC1_IfcTask_type; }
@@ -22304,39 +22304,39 @@ Ifc4x3_rc1::IfcTask::IfcTask(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwnerHist
 
 // Function implementations for IfcTaskTime
 boost::optional< ::Ifc4x3_rc1::IfcTaskDurationEnum::Value > Ifc4x3_rc1::IfcTaskTime::DurationType() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcTaskDurationEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x3_rc1::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x3_rc1::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTaskDurationEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x3_rc1::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTaskDurationEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::ScheduleDuration() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::EarlyStart() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::EarlyFinish() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::LateStart() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::LateFinish() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::FreeFloat() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::TotalFloat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcTaskTime::IsCritical() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } bool v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::StatusTime() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::ActualDuration() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::ActualStart() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } std::string v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::ActualFinish() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } std::string v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskTime::RemainingTime() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTaskTime::Completion() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } double v = *data_->getArgument(19); return v; }
-void Ifc4x3_rc1::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x3_rc1::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTaskTime::declaration() const { return *IFC4X3_RC1_IfcTaskTime_type; }
@@ -22358,7 +22358,7 @@ Ifc4x3_rc1::IfcTaskTimeRecurring::IfcTaskTimeRecurring(boost::optional< std::str
 ::Ifc4x3_rc1::IfcTaskTypeEnum::Value Ifc4x3_rc1::IfcTaskType::PredefinedType() const {  return ::Ifc4x3_rc1::IfcTaskTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc1::IfcTaskType::setPredefinedType(::Ifc4x3_rc1::IfcTaskTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcTaskTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTaskType::WorkMethod() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTaskType::declaration() const { return *IFC4X3_RC1_IfcTaskType_type; }
@@ -22368,17 +22368,17 @@ Ifc4x3_rc1::IfcTaskType::IfcTaskType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcTelecomAddress
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcTelecomAddress::TelephoneNumbers() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcTelecomAddress::FacsimileNumbers() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTelecomAddress::PagerNumber() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcTelecomAddress::ElectronicMailAddresses() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTelecomAddress::WWWHomePageURL() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc1::IfcTelecomAddress::MessagingIDs() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTelecomAddress::declaration() const { return *IFC4X3_RC1_IfcTelecomAddress_type; }
@@ -22388,21 +22388,21 @@ Ifc4x3_rc1::IfcTelecomAddress::IfcTelecomAddress(boost::optional< ::Ifc4x3_rc1::
 
 // Function implementations for IfcTendon
 boost::optional< ::Ifc4x3_rc1::IfcTendonTypeEnum::Value > Ifc4x3_rc1::IfcTendon::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc1::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTendonTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTendonTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTendon::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTendon::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTendon::TensionForce() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTendon::PreStress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc1::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTendon::FrictionCoefficient() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc1::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc1::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTendon::AnchorageSlip() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc1::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc1::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTendon::MinCurvatureRadius() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc1::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc1::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTendon::declaration() const { return *IFC4X3_RC1_IfcTendon_type; }
@@ -22412,7 +22412,7 @@ Ifc4x3_rc1::IfcTendon::IfcTendon(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwner
 
 // Function implementations for IfcTendonAnchor
 boost::optional< ::Ifc4x3_rc1::IfcTendonAnchorTypeEnum::Value > Ifc4x3_rc1::IfcTendonAnchor::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcTendonAnchorTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc1::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTendonAnchorTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTendonAnchorTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTendonAnchor::declaration() const { return *IFC4X3_RC1_IfcTendonAnchor_type; }
@@ -22454,11 +22454,11 @@ Ifc4x3_rc1::IfcTendonConduitType::IfcTendonConduitType(std::string v1_GlobalId,
 ::Ifc4x3_rc1::IfcTendonTypeEnum::Value Ifc4x3_rc1::IfcTendonType::PredefinedType() const {  return ::Ifc4x3_rc1::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc1::IfcTendonType::setPredefinedType(::Ifc4x3_rc1::IfcTendonTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcTendonTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTendonType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTendonType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTendonType::SheathDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTendonType::declaration() const { return *IFC4X3_RC1_IfcTendonType_type; }
@@ -22520,7 +22520,7 @@ void Ifc4x3_rc1::IfcTextStyle::setTextStyle(::Ifc4x3_rc1::IfcTextStyleTextModel*
 ::Ifc4x3_rc1::IfcTextFontSelect* Ifc4x3_rc1::IfcTextStyle::TextFontStyle() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcTextFontSelect>(true); }
 void Ifc4x3_rc1::IfcTextStyle::setTextFontStyle(::Ifc4x3_rc1::IfcTextFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcTextStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTextStyle::declaration() const { return *IFC4X3_RC1_IfcTextStyle_type; }
@@ -22532,11 +22532,11 @@ Ifc4x3_rc1::IfcTextStyle::IfcTextStyle(boost::optional< std::string > v1_Name, :
 std::vector< std::string > /*[1:?]*/ Ifc4x3_rc1::IfcTextStyleFontModel::FontFamily() const {  std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcTextStyleFontModel::setFontFamily(std::vector< std::string > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTextStyleFontModel::FontStyle() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTextStyleFontModel::FontVariant() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTextStyleFontModel::FontWeight() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc1::IfcSizeSelect* Ifc4x3_rc1::IfcTextStyleFontModel::FontSize() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc1::IfcSizeSelect>(true); }
 void Ifc4x3_rc1::IfcTextStyleFontModel::setFontSize(::Ifc4x3_rc1::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -22562,15 +22562,15 @@ Ifc4x3_rc1::IfcTextStyleForDefinedFont::IfcTextStyleForDefinedFont(::Ifc4x3_rc1:
 ::Ifc4x3_rc1::IfcSizeSelect* Ifc4x3_rc1::IfcTextStyleTextModel::TextIndent() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc1::IfcSizeSelect>(true); }
 void Ifc4x3_rc1::IfcTextStyleTextModel::setTextIndent(::Ifc4x3_rc1::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTextStyleTextModel::TextAlign() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTextStyleTextModel::TextDecoration() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc1::IfcSizeSelect* Ifc4x3_rc1::IfcTextStyleTextModel::LetterSpacing() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcSizeSelect>(true); }
 void Ifc4x3_rc1::IfcTextStyleTextModel::setLetterSpacing(::Ifc4x3_rc1::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc1::IfcSizeSelect* Ifc4x3_rc1::IfcTextStyleTextModel::WordSpacing() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc1::IfcSizeSelect>(true); }
 void Ifc4x3_rc1::IfcTextStyleTextModel::setWordSpacing(::Ifc4x3_rc1::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTextStyleTextModel::TextTransform() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc1::IfcSizeSelect* Ifc4x3_rc1::IfcTextStyleTextModel::LineHeight() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc1::IfcSizeSelect>(true); }
 void Ifc4x3_rc1::IfcTextStyleTextModel::setLineHeight(::Ifc4x3_rc1::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -22594,7 +22594,7 @@ Ifc4x3_rc1::IfcTextureCoordinate::IfcTextureCoordinate(aggregate_of< ::Ifc4x3_rc
 std::string Ifc4x3_rc1::IfcTextureCoordinateGenerator::Mode() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc1::IfcTextureCoordinateGenerator::setMode(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[1:?]*/ > Ifc4x3_rc1::IfcTextureCoordinateGenerator::Parameter() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTextureCoordinateGenerator::declaration() const { return *IFC4X3_RC1_IfcTextureCoordinateGenerator_type; }
@@ -22650,7 +22650,7 @@ Ifc4x3_rc1::IfcTimePeriod::IfcTimePeriod(std::string v1_StartTime, std::string v
 std::string Ifc4x3_rc1::IfcTimeSeries::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc1::IfcTimeSeries::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTimeSeries::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 std::string Ifc4x3_rc1::IfcTimeSeries::StartTime() const {  std::string v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc1::IfcTimeSeries::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::string Ifc4x3_rc1::IfcTimeSeries::EndTime() const {  std::string v = *data_->getArgument(3); return v; }
@@ -22660,7 +22660,7 @@ void Ifc4x3_rc1::IfcTimeSeries::setTimeSeriesDataType(::Ifc4x3_rc1::IfcTimeSerie
 ::Ifc4x3_rc1::IfcDataOriginEnum::Value Ifc4x3_rc1::IfcTimeSeries::DataOrigin() const {  return ::Ifc4x3_rc1::IfcDataOriginEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc1::IfcTimeSeries::setDataOrigin(::Ifc4x3_rc1::IfcDataOriginEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcDataOriginEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTimeSeries::UserDefinedDataOrigin() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc1::IfcUnit* Ifc4x3_rc1::IfcTimeSeries::Unit() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc1::IfcUnit>(true); }
 void Ifc4x3_rc1::IfcTimeSeries::setUnit(::Ifc4x3_rc1::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 
@@ -22711,7 +22711,7 @@ Ifc4x3_rc1::IfcToroidalSurface::IfcToroidalSurface(::Ifc4x3_rc1::IfcAxis2Placeme
 
 // Function implementations for IfcTrackElement
 boost::optional< ::Ifc4x3_rc1::IfcTrackElementTypeEnum::Value > Ifc4x3_rc1::IfcTrackElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcTrackElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcTrackElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTrackElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTrackElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcTrackElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTrackElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTrackElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTrackElement::declaration() const { return *IFC4X3_RC1_IfcTrackElement_type; }
@@ -22731,7 +22731,7 @@ Ifc4x3_rc1::IfcTrackElementType::IfcTrackElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcTransformer
 boost::optional< ::Ifc4x3_rc1::IfcTransformerTypeEnum::Value > Ifc4x3_rc1::IfcTransformer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcTransformerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTransformerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTransformerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTransformer::declaration() const { return *IFC4X3_RC1_IfcTransformer_type; }
@@ -22751,9 +22751,9 @@ Ifc4x3_rc1::IfcTransformerType::IfcTransformerType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcTransitionCurveSegment2D
 boost::optional< double > Ifc4x3_rc1::IfcTransitionCurveSegment2D::StartRadius() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc1::IfcTransitionCurveSegment2D::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc1::IfcTransitionCurveSegment2D::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcTransitionCurveSegment2D::EndRadius() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcTransitionCurveSegment2D::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcTransitionCurveSegment2D::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 bool Ifc4x3_rc1::IfcTransitionCurveSegment2D::IsStartRadiusCCW() const {  bool v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc1::IfcTransitionCurveSegment2D::setIsStartRadiusCCW(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 bool Ifc4x3_rc1::IfcTransitionCurveSegment2D::IsEndRadiusCCW() const {  bool v = *data_->getArgument(6); return v; }
@@ -22805,13 +22805,13 @@ Ifc4x3_rc1::IfcTrapeziumProfileDef::IfcTrapeziumProfileDef(::Ifc4x3_rc1::IfcProf
 
 // Function implementations for IfcTriangulatedFaceSet
 boost::optional< std::vector< std::vector< double > > > Ifc4x3_rc1::IfcTriangulatedFaceSet::Normals() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc1::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc1::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcTriangulatedFaceSet::Closed() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc1::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc1::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::vector< std::vector< int > > Ifc4x3_rc1::IfcTriangulatedFaceSet::CoordIndex() const {  std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc1::IfcTriangulatedFaceSet::setCoordIndex(std::vector< std::vector< int > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc1::IfcTriangulatedFaceSet::PnIndex() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTriangulatedFaceSet::declaration() const { return *IFC4X3_RC1_IfcTriangulatedFaceSet_type; }
@@ -22849,7 +22849,7 @@ Ifc4x3_rc1::IfcTrimmedCurve::IfcTrimmedCurve(::Ifc4x3_rc1::IfcCurve* v1_BasisCur
 
 // Function implementations for IfcTubeBundle
 boost::optional< ::Ifc4x3_rc1::IfcTubeBundleTypeEnum::Value > Ifc4x3_rc1::IfcTubeBundle::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcTubeBundleTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTubeBundleTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcTubeBundleTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcTubeBundle::declaration() const { return *IFC4X3_RC1_IfcTubeBundle_type; }
@@ -22869,9 +22869,9 @@ Ifc4x3_rc1::IfcTubeBundleType::IfcTubeBundleType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcTypeObject
 boost::optional< std::string > Ifc4x3_rc1::IfcTypeObject::ApplicableOccurrence() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPropertySetDefinition >::ptr > Ifc4x3_rc1::IfcTypeObject::HasPropertySets() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc1::IfcPropertySetDefinition >(); }
-void Ifc4x3_rc1::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc1::IfcRelDefinesByType::list::ptr Ifc4x3_rc1::IfcTypeObject::Types() const { return data_->getInverse(IFC4X3_RC1_IfcRelDefinesByType_type, 5)->as<IfcRelDefinesByType>(); }
 
@@ -22882,11 +22882,11 @@ Ifc4x3_rc1::IfcTypeObject::IfcTypeObject(std::string v1_GlobalId, ::Ifc4x3_rc1::
 
 // Function implementations for IfcTypeProcess
 boost::optional< std::string > Ifc4x3_rc1::IfcTypeProcess::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTypeProcess::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTypeProcess::ProcessType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc1::IfcRelAssignsToProcess::list::ptr Ifc4x3_rc1::IfcTypeProcess::OperatesOn() const { return data_->getInverse(IFC4X3_RC1_IfcRelAssignsToProcess_type, 6)->as<IfcRelAssignsToProcess>(); }
 
@@ -22897,9 +22897,9 @@ Ifc4x3_rc1::IfcTypeProcess::IfcTypeProcess(std::string v1_GlobalId, ::Ifc4x3_rc1
 
 // Function implementations for IfcTypeProduct
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcRepresentationMap >::ptr > Ifc4x3_rc1::IfcTypeProduct::RepresentationMaps() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc1::IfcRepresentationMap >(); }
-void Ifc4x3_rc1::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTypeProduct::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc1::IfcRelAssignsToProduct::list::ptr Ifc4x3_rc1::IfcTypeProduct::ReferencedBy() const { return data_->getInverse(IFC4X3_RC1_IfcRelAssignsToProduct_type, 6)->as<IfcRelAssignsToProduct>(); }
 
@@ -22910,11 +22910,11 @@ Ifc4x3_rc1::IfcTypeProduct::IfcTypeProduct(std::string v1_GlobalId, ::Ifc4x3_rc1
 
 // Function implementations for IfcTypeResource
 boost::optional< std::string > Ifc4x3_rc1::IfcTypeResource::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTypeResource::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcTypeResource::ResourceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc1::IfcRelAssignsToResource::list::ptr Ifc4x3_rc1::IfcTypeResource::ResourceOf() const { return data_->getInverse(IFC4X3_RC1_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -22933,11 +22933,11 @@ void Ifc4x3_rc1::IfcUShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc1::IfcUShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc1::IfcUShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcUShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcUShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcUShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcUShapeProfileDef::declaration() const { return *IFC4X3_RC1_IfcUShapeProfileDef_type; }
@@ -22957,7 +22957,7 @@ Ifc4x3_rc1::IfcUnitAssignment::IfcUnitAssignment(aggregate_of_instance::ptr v1_U
 
 // Function implementations for IfcUnitaryControlElement
 boost::optional< ::Ifc4x3_rc1::IfcUnitaryControlElementTypeEnum::Value > Ifc4x3_rc1::IfcUnitaryControlElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcUnitaryControlElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcUnitaryControlElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcUnitaryControlElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcUnitaryControlElement::declaration() const { return *IFC4X3_RC1_IfcUnitaryControlElement_type; }
@@ -22977,7 +22977,7 @@ Ifc4x3_rc1::IfcUnitaryControlElementType::IfcUnitaryControlElementType(std::stri
 
 // Function implementations for IfcUnitaryEquipment
 boost::optional< ::Ifc4x3_rc1::IfcUnitaryEquipmentTypeEnum::Value > Ifc4x3_rc1::IfcUnitaryEquipment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcUnitaryEquipmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcUnitaryEquipmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcUnitaryEquipmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcUnitaryEquipment::declaration() const { return *IFC4X3_RC1_IfcUnitaryEquipment_type; }
@@ -22997,7 +22997,7 @@ Ifc4x3_rc1::IfcUnitaryEquipmentType::IfcUnitaryEquipmentType(std::string v1_Glob
 
 // Function implementations for IfcValve
 boost::optional< ::Ifc4x3_rc1::IfcValveTypeEnum::Value > Ifc4x3_rc1::IfcValve::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcValveTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcValve::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcValveTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcValve::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcValveTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcValve::declaration() const { return *IFC4X3_RC1_IfcValve_type; }
@@ -23057,7 +23057,7 @@ Ifc4x3_rc1::IfcVertexPoint::IfcVertexPoint(::Ifc4x3_rc1::IfcPoint* v1_VertexGeom
 
 // Function implementations for IfcVibrationDamper
 boost::optional< ::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::Value > Ifc4x3_rc1::IfcVibrationDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcVibrationDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcVibrationDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcVibrationDamper::declaration() const { return *IFC4X3_RC1_IfcVibrationDamper_type; }
@@ -23067,7 +23067,7 @@ Ifc4x3_rc1::IfcVibrationDamper::IfcVibrationDamper(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcVibrationDamperType
 boost::optional< ::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::Value > Ifc4x3_rc1::IfcVibrationDamperType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc1::IfcVibrationDamperType::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcVibrationDamperType::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcVibrationDamperTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcVibrationDamperType::declaration() const { return *IFC4X3_RC1_IfcVibrationDamperType_type; }
@@ -23077,7 +23077,7 @@ Ifc4x3_rc1::IfcVibrationDamperType::IfcVibrationDamperType(std::string v1_Global
 
 // Function implementations for IfcVibrationIsolator
 boost::optional< ::Ifc4x3_rc1::IfcVibrationIsolatorTypeEnum::Value > Ifc4x3_rc1::IfcVibrationIsolator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcVibrationIsolatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcVibrationIsolatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcVibrationIsolatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcVibrationIsolator::declaration() const { return *IFC4X3_RC1_IfcVibrationIsolator_type; }
@@ -23125,7 +23125,7 @@ Ifc4x3_rc1::IfcVoidStratum::IfcVoidStratum(std::string v1_GlobalId, ::Ifc4x3_rc1
 
 // Function implementations for IfcVoidingFeature
 boost::optional< ::Ifc4x3_rc1::IfcVoidingFeatureTypeEnum::Value > Ifc4x3_rc1::IfcVoidingFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcVoidingFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcVoidingFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcVoidingFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcVoidingFeature::declaration() const { return *IFC4X3_RC1_IfcVoidingFeature_type; }
@@ -23135,7 +23135,7 @@ Ifc4x3_rc1::IfcVoidingFeature::IfcVoidingFeature(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcWall
 boost::optional< ::Ifc4x3_rc1::IfcWallTypeEnum::Value > Ifc4x3_rc1::IfcWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcWall::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcWall::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcWall::declaration() const { return *IFC4X3_RC1_IfcWall_type; }
@@ -23171,7 +23171,7 @@ Ifc4x3_rc1::IfcWallType::IfcWallType(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcWasteTerminal
 boost::optional< ::Ifc4x3_rc1::IfcWasteTerminalTypeEnum::Value > Ifc4x3_rc1::IfcWasteTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcWasteTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWasteTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWasteTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcWasteTerminal::declaration() const { return *IFC4X3_RC1_IfcWasteTerminal_type; }
@@ -23199,15 +23199,15 @@ Ifc4x3_rc1::IfcWaterStratum::IfcWaterStratum(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcWindow
 boost::optional< double > Ifc4x3_rc1::IfcWindow::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindow::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcWindowTypeEnum::Value > Ifc4x3_rc1::IfcWindow::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcWindowTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc1::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWindowTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWindowTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcWindowTypePartitioningEnum::Value > Ifc4x3_rc1::IfcWindow::PartitioningType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc1::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x3_rc1::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWindowTypePartitioningEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x3_rc1::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWindowTypePartitioningEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcWindow::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcWindow::declaration() const { return *IFC4X3_RC1_IfcWindow_type; }
@@ -23217,29 +23217,29 @@ Ifc4x3_rc1::IfcWindow::IfcWindow(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcOwner
 
 // Function implementations for IfcWindowLiningProperties
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::TransomThickness() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::MullionThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::FirstTransomOffset() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::SecondTransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::FirstMullionOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::SecondMullionOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 ::Ifc4x3_rc1::IfcShapeAspect* Ifc4x3_rc1::IfcWindowLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(12)))->as<::Ifc4x3_rc1::IfcShapeAspect>(true); }
 void Ifc4x3_rc1::IfcWindowLiningProperties::setShapeAspectStyle(::Ifc4x3_rc1::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::LiningOffset() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc1::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc1::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcWindowLiningProperties::declaration() const { return *IFC4X3_RC1_IfcWindowLiningProperties_type; }
@@ -23253,9 +23253,9 @@ void Ifc4x3_rc1::IfcWindowPanelProperties::setOperationType(::Ifc4x3_rc1::IfcWin
 ::Ifc4x3_rc1::IfcWindowPanelPositionEnum::Value Ifc4x3_rc1::IfcWindowPanelProperties::PanelPosition() const {  return ::Ifc4x3_rc1::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc1::IfcWindowPanelProperties::setPanelPosition(::Ifc4x3_rc1::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowPanelProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc1::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcWindowPanelProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc1::IfcShapeAspect* Ifc4x3_rc1::IfcWindowPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc1::IfcShapeAspect>(true); }
 void Ifc4x3_rc1::IfcWindowPanelProperties::setShapeAspectStyle(::Ifc4x3_rc1::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -23295,9 +23295,9 @@ void Ifc4x3_rc1::IfcWindowType::setPredefinedType(::Ifc4x3_rc1::IfcWindowTypeEnu
 ::Ifc4x3_rc1::IfcWindowTypePartitioningEnum::Value Ifc4x3_rc1::IfcWindowType::PartitioningType() const {  return ::Ifc4x3_rc1::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc1::IfcWindowType::setPartitioningType(::Ifc4x3_rc1::IfcWindowTypePartitioningEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc1::IfcWindowTypePartitioningEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x3_rc1::IfcWindowType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc1::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc1::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcWindowType::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcWindowType::declaration() const { return *IFC4X3_RC1_IfcWindowType_type; }
@@ -23307,11 +23307,11 @@ Ifc4x3_rc1::IfcWindowType::IfcWindowType(std::string v1_GlobalId, ::Ifc4x3_rc1::
 
 // Function implementations for IfcWorkCalendar
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcWorkTime >::ptr > Ifc4x3_rc1::IfcWorkCalendar::WorkingTimes() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc1::IfcWorkTime >(); }
-void Ifc4x3_rc1::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc1::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcWorkTime >::ptr > Ifc4x3_rc1::IfcWorkCalendar::ExceptionTimes() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc1::IfcWorkTime >(); }
-void Ifc4x3_rc1::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc1::IfcWorkCalendarTypeEnum::Value > Ifc4x3_rc1::IfcWorkCalendar::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcWorkCalendarTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc1::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWorkCalendarTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWorkCalendarTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcWorkCalendar::declaration() const { return *IFC4X3_RC1_IfcWorkCalendar_type; }
@@ -23323,17 +23323,17 @@ Ifc4x3_rc1::IfcWorkCalendar::IfcWorkCalendar(std::string v1_GlobalId, ::Ifc4x3_r
 std::string Ifc4x3_rc1::IfcWorkControl::CreationDate() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc1::IfcWorkControl::setCreationDate(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPerson >::ptr > Ifc4x3_rc1::IfcWorkControl::Creators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc1::IfcPerson >(); }
-void Ifc4x3_rc1::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x3_rc1::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcWorkControl::Purpose() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcWorkControl::Duration() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc1::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc1::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcWorkControl::TotalFloat() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc1::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc1::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 std::string Ifc4x3_rc1::IfcWorkControl::StartTime() const {  std::string v = *data_->getArgument(11); return v; }
 void Ifc4x3_rc1::IfcWorkControl::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcWorkControl::FinishTime() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc1::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc1::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcWorkControl::declaration() const { return *IFC4X3_RC1_IfcWorkControl_type; }
@@ -23343,7 +23343,7 @@ Ifc4x3_rc1::IfcWorkControl::IfcWorkControl(std::string v1_GlobalId, ::Ifc4x3_rc1
 
 // Function implementations for IfcWorkPlan
 boost::optional< ::Ifc4x3_rc1::IfcWorkPlanTypeEnum::Value > Ifc4x3_rc1::IfcWorkPlan::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcWorkPlanTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc1::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWorkPlanTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWorkPlanTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcWorkPlan::declaration() const { return *IFC4X3_RC1_IfcWorkPlan_type; }
@@ -23353,7 +23353,7 @@ Ifc4x3_rc1::IfcWorkPlan::IfcWorkPlan(std::string v1_GlobalId, ::Ifc4x3_rc1::IfcO
 
 // Function implementations for IfcWorkSchedule
 boost::optional< ::Ifc4x3_rc1::IfcWorkScheduleTypeEnum::Value > Ifc4x3_rc1::IfcWorkSchedule::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc1::IfcWorkScheduleTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc1::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWorkScheduleTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc1::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc1::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc1::IfcWorkScheduleTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcWorkSchedule::declaration() const { return *IFC4X3_RC1_IfcWorkSchedule_type; }
@@ -23365,9 +23365,9 @@ Ifc4x3_rc1::IfcWorkSchedule::IfcWorkSchedule(std::string v1_GlobalId, ::Ifc4x3_r
 ::Ifc4x3_rc1::IfcRecurrencePattern* Ifc4x3_rc1::IfcWorkTime::RecurrencePattern() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc1::IfcRecurrencePattern>(true); }
 void Ifc4x3_rc1::IfcWorkTime::setRecurrencePattern(::Ifc4x3_rc1::IfcRecurrencePattern* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcWorkTime::Start() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc1::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc1::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc1::IfcWorkTime::Finish() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcWorkTime::declaration() const { return *IFC4X3_RC1_IfcWorkTime_type; }
@@ -23385,9 +23385,9 @@ void Ifc4x3_rc1::IfcZShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc1::IfcZShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc1::IfcZShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcZShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc1::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc1::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc1::IfcZShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc1::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc1::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcZShapeProfileDef::declaration() const { return *IFC4X3_RC1_IfcZShapeProfileDef_type; }
@@ -23397,7 +23397,7 @@ Ifc4x3_rc1::IfcZShapeProfileDef::IfcZShapeProfileDef(::Ifc4x3_rc1::IfcProfileTyp
 
 // Function implementations for IfcZone
 boost::optional< std::string > Ifc4x3_rc1::IfcZone::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc1::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc1::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc1::IfcZone::declaration() const { return *IFC4X3_RC1_IfcZone_type; }
diff --git a/src/ifcparse/Ifc4x3_rc2.cpp b/src/ifcparse/Ifc4x3_rc2.cpp
index 344e3010e3..f461d1734d 100644
--- a/src/ifcparse/Ifc4x3_rc2.cpp
+++ b/src/ifcparse/Ifc4x3_rc2.cpp
@@ -13099,11 +13099,11 @@ Ifc4x3_rc2::IfcWarpingMomentMeasure::operator double() const { return *data_->ge
 
 // Function implementations for IfcActionRequest
 boost::optional< ::Ifc4x3_rc2::IfcActionRequestTypeEnum::Value > Ifc4x3_rc2::IfcActionRequest::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcActionRequestTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc2::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcActionRequestTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcActionRequestTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcActionRequest::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcActionRequest::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcActionRequest::declaration() const { return *IFC4X3_RC2_IfcActionRequest_type; }
@@ -13126,9 +13126,9 @@ Ifc4x3_rc2::IfcActor::IfcActor(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHi
 ::Ifc4x3_rc2::IfcRoleEnum::Value Ifc4x3_rc2::IfcActorRole::Role() const {  return ::Ifc4x3_rc2::IfcRoleEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc2::IfcActorRole::setRole(::Ifc4x3_rc2::IfcRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcRoleEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcActorRole::UserDefinedRole() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcActorRole::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc2::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc2::IfcActorRole::HasExternalReference() const { return data_->getInverse(IFC4X3_RC2_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -13139,7 +13139,7 @@ Ifc4x3_rc2::IfcActorRole::IfcActorRole(::Ifc4x3_rc2::IfcRoleEnum::Value v1_Role,
 
 // Function implementations for IfcActuator
 boost::optional< ::Ifc4x3_rc2::IfcActuatorTypeEnum::Value > Ifc4x3_rc2::IfcActuator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcActuatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcActuatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcActuatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcActuator::declaration() const { return *IFC4X3_RC2_IfcActuator_type; }
@@ -13159,11 +13159,11 @@ Ifc4x3_rc2::IfcActuatorType::IfcActuatorType(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcAddress
 boost::optional< ::Ifc4x3_rc2::IfcAddressTypeEnum::Value > Ifc4x3_rc2::IfcAddress::Purpose() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcAddressTypeEnum::FromString(*data_->getArgument(0)); }
-void Ifc4x3_rc2::IfcAddress::setPurpose(boost::optional< ::Ifc4x3_rc2::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAddressTypeEnum::ToString(*v)));data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcAddress::setPurpose(boost::optional< ::Ifc4x3_rc2::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAddressTypeEnum::ToString(*v)));}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcAddress::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcAddress::UserDefinedPurpose() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc2::IfcPerson::list::ptr Ifc4x3_rc2::IfcAddress::OfPerson() const { return data_->getInverse(IFC4X3_RC2_IfcPerson_type, 7)->as<IfcPerson>(); }
 ::Ifc4x3_rc2::IfcOrganization::list::ptr Ifc4x3_rc2::IfcAddress::OfOrganization() const { return data_->getInverse(IFC4X3_RC2_IfcOrganization_type, 4)->as<IfcOrganization>(); }
@@ -13201,7 +13201,7 @@ Ifc4x3_rc2::IfcAdvancedFace::IfcAdvancedFace(aggregate_of< ::Ifc4x3_rc2::IfcFace
 
 // Function implementations for IfcAirTerminal
 boost::optional< ::Ifc4x3_rc2::IfcAirTerminalTypeEnum::Value > Ifc4x3_rc2::IfcAirTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcAirTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAirTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAirTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcAirTerminal::declaration() const { return *IFC4X3_RC2_IfcAirTerminal_type; }
@@ -13211,7 +13211,7 @@ Ifc4x3_rc2::IfcAirTerminal::IfcAirTerminal(std::string v1_GlobalId, ::Ifc4x3_rc2
 
 // Function implementations for IfcAirTerminalBox
 boost::optional< ::Ifc4x3_rc2::IfcAirTerminalBoxTypeEnum::Value > Ifc4x3_rc2::IfcAirTerminalBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcAirTerminalBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAirTerminalBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAirTerminalBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcAirTerminalBox::declaration() const { return *IFC4X3_RC2_IfcAirTerminalBox_type; }
@@ -13241,7 +13241,7 @@ Ifc4x3_rc2::IfcAirTerminalType::IfcAirTerminalType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcAirToAirHeatRecovery
 boost::optional< ::Ifc4x3_rc2::IfcAirToAirHeatRecoveryTypeEnum::Value > Ifc4x3_rc2::IfcAirToAirHeatRecovery::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcAirToAirHeatRecoveryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcAirToAirHeatRecovery::declaration() const { return *IFC4X3_RC2_IfcAirToAirHeatRecovery_type; }
@@ -13261,7 +13261,7 @@ Ifc4x3_rc2::IfcAirToAirHeatRecoveryType::IfcAirToAirHeatRecoveryType(std::string
 
 // Function implementations for IfcAlarm
 boost::optional< ::Ifc4x3_rc2::IfcAlarmTypeEnum::Value > Ifc4x3_rc2::IfcAlarm::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcAlarmTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAlarmTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAlarmTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcAlarm::declaration() const { return *IFC4X3_RC2_IfcAlarm_type; }
@@ -13281,7 +13281,7 @@ Ifc4x3_rc2::IfcAlarmType::IfcAlarmType(std::string v1_GlobalId, ::Ifc4x3_rc2::If
 
 // Function implementations for IfcAlignment
 boost::optional< ::Ifc4x3_rc2::IfcAlignmentTypeEnum::Value > Ifc4x3_rc2::IfcAlignment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcAlignmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAlignmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAlignmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcAlignment::declaration() const { return *IFC4X3_RC2_IfcAlignment_type; }
@@ -13341,13 +13341,13 @@ void Ifc4x3_rc2::IfcAlignmentCantSegment::setHorizontalLength(double v) { {IfcWr
 double Ifc4x3_rc2::IfcAlignmentCantSegment::StartCantLeft() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc2::IfcAlignmentCantSegment::setStartCantLeft(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAlignmentCantSegment::EndCantLeft() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcAlignmentCantSegment::setEndCantLeft(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcAlignmentCantSegment::setEndCantLeft(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 double Ifc4x3_rc2::IfcAlignmentCantSegment::StartCantRight() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcAlignmentCantSegment::setStartCantRight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAlignmentCantSegment::EndCantRight() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcAlignmentCantSegment::setEndCantRight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcAlignmentCantSegment::setEndCantRight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAlignmentCantSegment::SmoothingLength() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcAlignmentCantSegment::setSmoothingLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcAlignmentCantSegment::setSmoothingLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc2::IfcAlignmentCantSegmentTypeEnum::Value Ifc4x3_rc2::IfcAlignmentCantSegment::PredefinedType() const {  return ::Ifc4x3_rc2::IfcAlignmentCantSegmentTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc2::IfcAlignmentCantSegment::setPredefinedType(::Ifc4x3_rc2::IfcAlignmentCantSegmentTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcAlignmentCantSegmentTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 
@@ -13363,7 +13363,7 @@ void Ifc4x3_rc2::IfcAlignmentCurve::setHorizontal(::Ifc4x3_rc2::IfcAlignmentHori
 ::Ifc4x3_rc2::IfcAlignmentVertical* Ifc4x3_rc2::IfcAlignmentCurve::Vertical() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc2::IfcAlignmentVertical>(true); }
 void Ifc4x3_rc2::IfcAlignmentCurve::setVertical(::Ifc4x3_rc2::IfcAlignmentVertical* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcAlignmentCurve::Tag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcAlignmentCurve::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcAlignmentCurve::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcAlignmentCurve::declaration() const { return *IFC4X3_RC2_IfcAlignmentCurve_type; }
@@ -13373,7 +13373,7 @@ Ifc4x3_rc2::IfcAlignmentCurve::IfcAlignmentCurve(::Ifc4x3_rc2::IfcAlignmentHoriz
 
 // Function implementations for IfcAlignmentHorizontal
 boost::optional< double > Ifc4x3_rc2::IfcAlignmentHorizontal::StartDistAlong() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcAlignmentHorizontal::setStartDistAlong(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcAlignmentHorizontal::setStartDistAlong(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 aggregate_of< ::Ifc4x3_rc2::IfcAlignmentHorizontalSegment >::ptr Ifc4x3_rc2::IfcAlignmentHorizontal::Segments() const {  aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc2::IfcAlignmentHorizontalSegment >(); }
 void Ifc4x3_rc2::IfcAlignmentHorizontal::setSegments(aggregate_of< ::Ifc4x3_rc2::IfcAlignmentHorizontalSegment >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(8,attr);} }
 
@@ -13395,7 +13395,7 @@ void Ifc4x3_rc2::IfcAlignmentHorizontalSegment::setEndRadiusOfCurvature(double v
 double Ifc4x3_rc2::IfcAlignmentHorizontalSegment::SegmentLength() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcAlignmentHorizontalSegment::setSegmentLength(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAlignmentHorizontalSegment::GravityCenterLineHeight() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcAlignmentHorizontalSegment::setGravityCenterLineHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcAlignmentHorizontalSegment::setGravityCenterLineHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc2::IfcAlignmentHorizontalSegmentTypeEnum::Value Ifc4x3_rc2::IfcAlignmentHorizontalSegment::PredefinedType() const {  return ::Ifc4x3_rc2::IfcAlignmentHorizontalSegmentTypeEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc2::IfcAlignmentHorizontalSegment::setPredefinedType(::Ifc4x3_rc2::IfcAlignmentHorizontalSegmentTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcAlignmentHorizontalSegmentTypeEnum::ToString(v)));data_->setArgument(8,attr);} }
 
@@ -13407,9 +13407,9 @@ Ifc4x3_rc2::IfcAlignmentHorizontalSegment::IfcAlignmentHorizontalSegment(boost::
 
 // Function implementations for IfcAlignmentParameterSegment
 boost::optional< std::string > Ifc4x3_rc2::IfcAlignmentParameterSegment::StartTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcAlignmentParameterSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcAlignmentParameterSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcAlignmentParameterSegment::EndTag() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcAlignmentParameterSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcAlignmentParameterSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcAlignmentParameterSegment::declaration() const { return *IFC4X3_RC2_IfcAlignmentParameterSegment_type; }
@@ -13449,7 +13449,7 @@ void Ifc4x3_rc2::IfcAlignmentVerticalSegment::setStartGradient(double v) { {IfcW
 double Ifc4x3_rc2::IfcAlignmentVerticalSegment::EndGradient() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcAlignmentVerticalSegment::setEndGradient(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAlignmentVerticalSegment::RadiusOfCurvature() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcAlignmentVerticalSegment::setRadiusOfCurvature(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcAlignmentVerticalSegment::setRadiusOfCurvature(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc2::IfcAlignmentVerticalSegmentTypeEnum::Value Ifc4x3_rc2::IfcAlignmentVerticalSegment::PredefinedType() const {  return ::Ifc4x3_rc2::IfcAlignmentVerticalSegmentTypeEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc2::IfcAlignmentVerticalSegment::setPredefinedType(::Ifc4x3_rc2::IfcAlignmentVerticalSegmentTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcAlignmentVerticalSegmentTypeEnum::ToString(v)));data_->setArgument(8,attr);} }
 
@@ -13461,7 +13461,7 @@ Ifc4x3_rc2::IfcAlignmentVerticalSegment::IfcAlignmentVerticalSegment(boost::opti
 
 // Function implementations for IfcAnnotation
 boost::optional< ::Ifc4x3_rc2::IfcAnnotationTypeEnum::Value > Ifc4x3_rc2::IfcAnnotation::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcAnnotationTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc2::IfcAnnotation::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAnnotationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAnnotationTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcAnnotation::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAnnotationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAnnotationTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc2::IfcRelContainedInSpatialStructure::list::ptr Ifc4x3_rc2::IfcAnnotation::ContainedInStructure() const { return data_->getInverse(IFC4X3_RC2_IfcRelContainedInSpatialStructure_type, 4)->as<IfcRelContainedInSpatialStructure>(); }
 
@@ -13474,7 +13474,7 @@ Ifc4x3_rc2::IfcAnnotation::IfcAnnotation(std::string v1_GlobalId, ::Ifc4x3_rc2::
 ::Ifc4x3_rc2::IfcCurve* Ifc4x3_rc2::IfcAnnotationFillArea::OuterBoundary() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc2::IfcCurve>(true); }
 void Ifc4x3_rc2::IfcAnnotationFillArea::setOuterBoundary(::Ifc4x3_rc2::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcCurve >::ptr > Ifc4x3_rc2::IfcAnnotationFillArea::InnerBoundaries() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc2::IfcCurve >(); }
-void Ifc4x3_rc2::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcAnnotationFillArea::declaration() const { return *IFC4X3_RC2_IfcAnnotationFillArea_type; }
@@ -13500,25 +13500,25 @@ Ifc4x3_rc2::IfcApplication::IfcApplication(::Ifc4x3_rc2::IfcOrganization* v1_App
 
 // Function implementations for IfcAppliedValue
 boost::optional< std::string > Ifc4x3_rc2::IfcAppliedValue::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcAppliedValue::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc2::IfcAppliedValueSelect* Ifc4x3_rc2::IfcAppliedValue::AppliedValue() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc2::IfcAppliedValueSelect>(true); }
 void Ifc4x3_rc2::IfcAppliedValue::setAppliedValue(::Ifc4x3_rc2::IfcAppliedValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcMeasureWithUnit* Ifc4x3_rc2::IfcAppliedValue::UnitBasis() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcMeasureWithUnit>(true); }
 void Ifc4x3_rc2::IfcAppliedValue::setUnitBasis(::Ifc4x3_rc2::IfcMeasureWithUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcAppliedValue::ApplicableDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcAppliedValue::FixedUntilDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcAppliedValue::Category() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcAppliedValue::Condition() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcArithmeticOperatorEnum::Value > Ifc4x3_rc2::IfcAppliedValue::ArithmeticOperator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcArithmeticOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x3_rc2::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcArithmeticOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x3_rc2::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcArithmeticOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAppliedValue >::ptr > Ifc4x3_rc2::IfcAppliedValue::Components() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc2::IfcAppliedValue >(); }
-void Ifc4x3_rc2::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 
 ::Ifc4x3_rc2::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc2::IfcAppliedValue::HasExternalReference() const { return data_->getInverse(IFC4X3_RC2_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -13529,19 +13529,19 @@ Ifc4x3_rc2::IfcAppliedValue::IfcAppliedValue(boost::optional< std::string > v1_N
 
 // Function implementations for IfcApproval
 boost::optional< std::string > Ifc4x3_rc2::IfcApproval::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcApproval::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcApproval::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcApproval::TimeOfApproval() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcApproval::Status() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcApproval::Level() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcApproval::Qualifier() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc2::IfcActorSelect* Ifc4x3_rc2::IfcApproval::RequestingApproval() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc2::IfcActorSelect>(true); }
 void Ifc4x3_rc2::IfcApproval::setRequestingApproval(::Ifc4x3_rc2::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x3_rc2::IfcActorSelect* Ifc4x3_rc2::IfcApproval::GivingApproval() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc2::IfcActorSelect>(true); }
@@ -13602,7 +13602,7 @@ Ifc4x3_rc2::IfcArbitraryProfileDefWithVoids::IfcArbitraryProfileDefWithVoids(::I
 
 // Function implementations for IfcAsset
 boost::optional< std::string > Ifc4x3_rc2::IfcAsset::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc2::IfcCostValue* Ifc4x3_rc2::IfcAsset::OriginalValue() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcCostValue>(true); }
 void Ifc4x3_rc2::IfcAsset::setOriginalValue(::Ifc4x3_rc2::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 ::Ifc4x3_rc2::IfcCostValue* Ifc4x3_rc2::IfcAsset::CurrentValue() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc2::IfcCostValue>(true); }
@@ -13616,7 +13616,7 @@ void Ifc4x3_rc2::IfcAsset::setUser(::Ifc4x3_rc2::IfcActorSelect* v) { {IfcWrite:
 ::Ifc4x3_rc2::IfcPerson* Ifc4x3_rc2::IfcAsset::ResponsiblePerson() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc2::IfcPerson>(true); }
 void Ifc4x3_rc2::IfcAsset::setResponsiblePerson(::Ifc4x3_rc2::IfcPerson* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcAsset::IncorporationDate() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x3_rc2::IfcCostValue* Ifc4x3_rc2::IfcAsset::DepreciatedValue() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x3_rc2::IfcCostValue>(true); }
 void Ifc4x3_rc2::IfcAsset::setDepreciatedValue(::Ifc4x3_rc2::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -13636,21 +13636,21 @@ void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setWebThickness(double v) { {Ifc
 double Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::BottomFlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setBottomFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::BottomFlangeFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 double Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::TopFlangeWidth() const {  double v = *data_->getArgument(8); return v; }
 void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setTopFlangeWidth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::TopFlangeThickness() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::TopFlangeFilletRadius() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::BottomFlangeEdgeRadius() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::BottomFlangeSlope() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::TopFlangeEdgeRadius() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::TopFlangeSlope() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::declaration() const { return *IFC4X3_RC2_IfcAsymmetricIShapeProfileDef_type; }
@@ -13660,7 +13660,7 @@ Ifc4x3_rc2::IfcAsymmetricIShapeProfileDef::IfcAsymmetricIShapeProfileDef(::Ifc4x
 
 // Function implementations for IfcAudioVisualAppliance
 boost::optional< ::Ifc4x3_rc2::IfcAudioVisualApplianceTypeEnum::Value > Ifc4x3_rc2::IfcAudioVisualAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcAudioVisualApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAudioVisualApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAudioVisualApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcAudioVisualAppliance::declaration() const { return *IFC4X3_RC2_IfcAudioVisualAppliance_type; }
@@ -13805,7 +13805,7 @@ Ifc4x3_rc2::IfcBSplineSurfaceWithKnots::IfcBSplineSurfaceWithKnots(int v1_UDegre
 
 // Function implementations for IfcBeam
 boost::optional< ::Ifc4x3_rc2::IfcBeamTypeEnum::Value > Ifc4x3_rc2::IfcBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBeam::declaration() const { return *IFC4X3_RC2_IfcBeam_type; }
@@ -13833,7 +13833,7 @@ Ifc4x3_rc2::IfcBeamType::IfcBeamType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcBearing
 boost::optional< ::Ifc4x3_rc2::IfcBearingTypeEnum::Value > Ifc4x3_rc2::IfcBearing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcBearingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcBearing::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBearingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBearingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcBearing::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBearingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBearingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBearing::declaration() const { return *IFC4X3_RC2_IfcBearing_type; }
@@ -13893,7 +13893,7 @@ Ifc4x3_rc2::IfcBlossCurve::IfcBlossCurve(::Ifc4x3_rc2::IfcAxis2Placement* v1_Pos
 
 // Function implementations for IfcBoiler
 boost::optional< ::Ifc4x3_rc2::IfcBoilerTypeEnum::Value > Ifc4x3_rc2::IfcBoiler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcBoilerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBoilerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBoilerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBoiler::declaration() const { return *IFC4X3_RC2_IfcBoiler_type; }
@@ -13943,7 +13943,7 @@ Ifc4x3_rc2::IfcBorehole::IfcBorehole(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcBoundaryCondition
 boost::optional< std::string > Ifc4x3_rc2::IfcBoundaryCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBoundaryCondition::declaration() const { return *IFC4X3_RC2_IfcBoundaryCondition_type; }
@@ -14068,7 +14068,7 @@ Ifc4x3_rc2::IfcBoxedHalfSpace::IfcBoxedHalfSpace(::Ifc4x3_rc2::IfcSurface* v1_Ba
 
 // Function implementations for IfcBridge
 boost::optional< ::Ifc4x3_rc2::IfcBridgeTypeEnum::Value > Ifc4x3_rc2::IfcBridge::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcBridgeTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc2::IfcBridge::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBridgeTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBridgeTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcBridge::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBridgeTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBridgeTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBridge::declaration() const { return *IFC4X3_RC2_IfcBridge_type; }
@@ -14086,9 +14086,9 @@ Ifc4x3_rc2::IfcBridgePart::IfcBridgePart(std::string v1_GlobalId, ::Ifc4x3_rc2::
 
 // Function implementations for IfcBuilding
 boost::optional< double > Ifc4x3_rc2::IfcBuilding::ElevationOfRefHeight() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcBuilding::ElevationOfTerrain() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc2::IfcPostalAddress* Ifc4x3_rc2::IfcBuilding::BuildingAddress() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc2::IfcPostalAddress>(true); }
 void Ifc4x3_rc2::IfcBuilding::setBuildingAddress(::Ifc4x3_rc2::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 
@@ -14100,7 +14100,7 @@ Ifc4x3_rc2::IfcBuilding::IfcBuilding(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcBuildingElementPart
 boost::optional< ::Ifc4x3_rc2::IfcBuildingElementPartTypeEnum::Value > Ifc4x3_rc2::IfcBuildingElementPart::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcBuildingElementPartTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBuildingElementPartTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBuildingElementPartTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBuildingElementPart::declaration() const { return *IFC4X3_RC2_IfcBuildingElementPart_type; }
@@ -14120,7 +14120,7 @@ Ifc4x3_rc2::IfcBuildingElementPartType::IfcBuildingElementPartType(std::string v
 
 // Function implementations for IfcBuildingElementProxy
 boost::optional< ::Ifc4x3_rc2::IfcBuildingElementProxyTypeEnum::Value > Ifc4x3_rc2::IfcBuildingElementProxy::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcBuildingElementProxyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBuildingElementProxyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBuildingElementProxyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBuildingElementProxy::declaration() const { return *IFC4X3_RC2_IfcBuildingElementProxy_type; }
@@ -14140,7 +14140,7 @@ Ifc4x3_rc2::IfcBuildingElementProxyType::IfcBuildingElementProxyType(std::string
 
 // Function implementations for IfcBuildingStorey
 boost::optional< double > Ifc4x3_rc2::IfcBuildingStorey::Elevation() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBuildingStorey::declaration() const { return *IFC4X3_RC2_IfcBuildingStorey_type; }
@@ -14150,9 +14150,9 @@ Ifc4x3_rc2::IfcBuildingStorey::IfcBuildingStorey(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcBuildingSystem
 boost::optional< ::Ifc4x3_rc2::IfcBuildingSystemTypeEnum::Value > Ifc4x3_rc2::IfcBuildingSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcBuildingSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc2::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBuildingSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBuildingSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcBuildingSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBuildingSystem::declaration() const { return *IFC4X3_RC2_IfcBuildingSystem_type; }
@@ -14178,9 +14178,9 @@ Ifc4x3_rc2::IfcBuiltElementType::IfcBuiltElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcBuiltSystem
 boost::optional< ::Ifc4x3_rc2::IfcBuiltSystemTypeEnum::Value > Ifc4x3_rc2::IfcBuiltSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcBuiltSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc2::IfcBuiltSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBuiltSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBuiltSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcBuiltSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBuiltSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBuiltSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcBuiltSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcBuiltSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcBuiltSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBuiltSystem::declaration() const { return *IFC4X3_RC2_IfcBuiltSystem_type; }
@@ -14190,7 +14190,7 @@ Ifc4x3_rc2::IfcBuiltSystem::IfcBuiltSystem(std::string v1_GlobalId, ::Ifc4x3_rc2
 
 // Function implementations for IfcBurner
 boost::optional< ::Ifc4x3_rc2::IfcBurnerTypeEnum::Value > Ifc4x3_rc2::IfcBurner::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcBurnerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBurnerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcBurnerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcBurner::declaration() const { return *IFC4X3_RC2_IfcBurner_type; }
@@ -14218,7 +14218,7 @@ void Ifc4x3_rc2::IfcCShapeProfileDef::setWallThickness(double v) { {IfcWrite::If
 double Ifc4x3_rc2::IfcCShapeProfileDef::Girth() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcCShapeProfileDef::setGirth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcCShapeProfileDef::InternalFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCShapeProfileDef::declaration() const { return *IFC4X3_RC2_IfcCShapeProfileDef_type; }
@@ -14228,7 +14228,7 @@ Ifc4x3_rc2::IfcCShapeProfileDef::IfcCShapeProfileDef(::Ifc4x3_rc2::IfcProfileTyp
 
 // Function implementations for IfcCableCarrierFitting
 boost::optional< ::Ifc4x3_rc2::IfcCableCarrierFittingTypeEnum::Value > Ifc4x3_rc2::IfcCableCarrierFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCableCarrierFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCableCarrierFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCableCarrierFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCableCarrierFitting::declaration() const { return *IFC4X3_RC2_IfcCableCarrierFitting_type; }
@@ -14248,7 +14248,7 @@ Ifc4x3_rc2::IfcCableCarrierFittingType::IfcCableCarrierFittingType(std::string v
 
 // Function implementations for IfcCableCarrierSegment
 boost::optional< ::Ifc4x3_rc2::IfcCableCarrierSegmentTypeEnum::Value > Ifc4x3_rc2::IfcCableCarrierSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCableCarrierSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCableCarrierSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCableCarrierSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCableCarrierSegment::declaration() const { return *IFC4X3_RC2_IfcCableCarrierSegment_type; }
@@ -14268,7 +14268,7 @@ Ifc4x3_rc2::IfcCableCarrierSegmentType::IfcCableCarrierSegmentType(std::string v
 
 // Function implementations for IfcCableFitting
 boost::optional< ::Ifc4x3_rc2::IfcCableFittingTypeEnum::Value > Ifc4x3_rc2::IfcCableFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCableFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCableFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCableFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCableFitting::declaration() const { return *IFC4X3_RC2_IfcCableFitting_type; }
@@ -14288,7 +14288,7 @@ Ifc4x3_rc2::IfcCableFittingType::IfcCableFittingType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcCableSegment
 boost::optional< ::Ifc4x3_rc2::IfcCableSegmentTypeEnum::Value > Ifc4x3_rc2::IfcCableSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCableSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCableSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCableSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCableSegment::declaration() const { return *IFC4X3_RC2_IfcCableSegment_type; }
@@ -14308,7 +14308,7 @@ Ifc4x3_rc2::IfcCableSegmentType::IfcCableSegmentType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcCaissonFoundation
 boost::optional< ::Ifc4x3_rc2::IfcCaissonFoundationTypeEnum::Value > Ifc4x3_rc2::IfcCaissonFoundation::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCaissonFoundationTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCaissonFoundation::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCaissonFoundationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCaissonFoundationTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCaissonFoundation::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCaissonFoundationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCaissonFoundationTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCaissonFoundation::declaration() const { return *IFC4X3_RC2_IfcCaissonFoundation_type; }
@@ -14348,7 +14348,7 @@ Ifc4x3_rc2::IfcCartesianPointList::IfcCartesianPointList() : IfcGeometricReprese
 std::vector< std::vector< double > > Ifc4x3_rc2::IfcCartesianPointList2D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc2::IfcCartesianPointList2D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcCartesianPointList2D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCartesianPointList2D::declaration() const { return *IFC4X3_RC2_IfcCartesianPointList2D_type; }
@@ -14360,7 +14360,7 @@ Ifc4x3_rc2::IfcCartesianPointList2D::IfcCartesianPointList2D(std::vector< std::v
 std::vector< std::vector< double > > Ifc4x3_rc2::IfcCartesianPointList3D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc2::IfcCartesianPointList3D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcCartesianPointList3D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCartesianPointList3D::declaration() const { return *IFC4X3_RC2_IfcCartesianPointList3D_type; }
@@ -14376,7 +14376,7 @@ void Ifc4x3_rc2::IfcCartesianTransformationOperator::setAxis2(::Ifc4x3_rc2::IfcD
 ::Ifc4x3_rc2::IfcCartesianPoint* Ifc4x3_rc2::IfcCartesianTransformationOperator::LocalOrigin() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc2::IfcCartesianPoint>(true); }
 void Ifc4x3_rc2::IfcCartesianTransformationOperator::setLocalOrigin(::Ifc4x3_rc2::IfcCartesianPoint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcCartesianTransformationOperator::Scale() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCartesianTransformationOperator::declaration() const { return *IFC4X3_RC2_IfcCartesianTransformationOperator_type; }
@@ -14394,7 +14394,7 @@ Ifc4x3_rc2::IfcCartesianTransformationOperator2D::IfcCartesianTransformationOper
 
 // Function implementations for IfcCartesianTransformationOperator2DnonUniform
 boost::optional< double > Ifc4x3_rc2::IfcCartesianTransformationOperator2DnonUniform::Scale2() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCartesianTransformationOperator2DnonUniform::declaration() const { return *IFC4X3_RC2_IfcCartesianTransformationOperator2DnonUniform_type; }
@@ -14414,9 +14414,9 @@ Ifc4x3_rc2::IfcCartesianTransformationOperator3D::IfcCartesianTransformationOper
 
 // Function implementations for IfcCartesianTransformationOperator3DnonUniform
 boost::optional< double > Ifc4x3_rc2::IfcCartesianTransformationOperator3DnonUniform::Scale2() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcCartesianTransformationOperator3DnonUniform::Scale3() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCartesianTransformationOperator3DnonUniform::declaration() const { return *IFC4X3_RC2_IfcCartesianTransformationOperator3DnonUniform_type; }
@@ -14436,7 +14436,7 @@ Ifc4x3_rc2::IfcCenterLineProfileDef::IfcCenterLineProfileDef(::Ifc4x3_rc2::IfcPr
 
 // Function implementations for IfcChiller
 boost::optional< ::Ifc4x3_rc2::IfcChillerTypeEnum::Value > Ifc4x3_rc2::IfcChiller::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcChillerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcChillerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcChillerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcChiller::declaration() const { return *IFC4X3_RC2_IfcChiller_type; }
@@ -14456,7 +14456,7 @@ Ifc4x3_rc2::IfcChillerType::IfcChillerType(std::string v1_GlobalId, ::Ifc4x3_rc2
 
 // Function implementations for IfcChimney
 boost::optional< ::Ifc4x3_rc2::IfcChimneyTypeEnum::Value > Ifc4x3_rc2::IfcChimney::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcChimneyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcChimneyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcChimneyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcChimney::declaration() const { return *IFC4X3_RC2_IfcChimney_type; }
@@ -14534,19 +14534,19 @@ Ifc4x3_rc2::IfcCivilElementType::IfcCivilElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcClassification
 boost::optional< std::string > Ifc4x3_rc2::IfcClassification::Source() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcClassification::Edition() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcClassification::EditionDate() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::string Ifc4x3_rc2::IfcClassification::Name() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcClassification::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcClassification::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcClassification::Location() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcClassification::ReferenceTokens() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc2::IfcRelAssociatesClassification::list::ptr Ifc4x3_rc2::IfcClassification::ClassificationForObjects() const { return data_->getInverse(IFC4X3_RC2_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x3_rc2::IfcClassificationReference::list::ptr Ifc4x3_rc2::IfcClassification::HasReferences() const { return data_->getInverse(IFC4X3_RC2_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -14560,9 +14560,9 @@ Ifc4x3_rc2::IfcClassification::IfcClassification(boost::optional< std::string >
 ::Ifc4x3_rc2::IfcClassificationReferenceSelect* Ifc4x3_rc2::IfcClassificationReference::ReferencedSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcClassificationReferenceSelect>(true); }
 void Ifc4x3_rc2::IfcClassificationReference::setReferencedSource(::Ifc4x3_rc2::IfcClassificationReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcClassificationReference::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcClassificationReference::Sort() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc2::IfcRelAssociatesClassification::list::ptr Ifc4x3_rc2::IfcClassificationReference::ClassificationRefForObjects() const { return data_->getInverse(IFC4X3_RC2_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x3_rc2::IfcClassificationReference::list::ptr Ifc4x3_rc2::IfcClassificationReference::HasReferences() const { return data_->getInverse(IFC4X3_RC2_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -14594,7 +14594,7 @@ Ifc4x3_rc2::IfcClothoid::IfcClothoid(::Ifc4x3_rc2::IfcAxis2Placement* v1_Positio
 
 // Function implementations for IfcCoil
 boost::optional< ::Ifc4x3_rc2::IfcCoilTypeEnum::Value > Ifc4x3_rc2::IfcCoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCoil::declaration() const { return *IFC4X3_RC2_IfcCoil_type; }
@@ -14638,7 +14638,7 @@ Ifc4x3_rc2::IfcColourRgbList::IfcColourRgbList(std::vector< std::vector< double
 
 // Function implementations for IfcColourSpecification
 boost::optional< std::string > Ifc4x3_rc2::IfcColourSpecification::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcColourSpecification::declaration() const { return *IFC4X3_RC2_IfcColourSpecification_type; }
@@ -14648,7 +14648,7 @@ Ifc4x3_rc2::IfcColourSpecification::IfcColourSpecification(boost::optional< std:
 
 // Function implementations for IfcColumn
 boost::optional< ::Ifc4x3_rc2::IfcColumnTypeEnum::Value > Ifc4x3_rc2::IfcColumn::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcColumnTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcColumnTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcColumnTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcColumn::declaration() const { return *IFC4X3_RC2_IfcColumn_type; }
@@ -14676,7 +14676,7 @@ Ifc4x3_rc2::IfcColumnType::IfcColumnType(std::string v1_GlobalId, ::Ifc4x3_rc2::
 
 // Function implementations for IfcCommunicationsAppliance
 boost::optional< ::Ifc4x3_rc2::IfcCommunicationsApplianceTypeEnum::Value > Ifc4x3_rc2::IfcCommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCommunicationsAppliance::declaration() const { return *IFC4X3_RC2_IfcCommunicationsAppliance_type; }
@@ -14708,11 +14708,11 @@ Ifc4x3_rc2::IfcComplexProperty::IfcComplexProperty(std::string v1_Name, boost::o
 
 // Function implementations for IfcComplexPropertyTemplate
 boost::optional< std::string > Ifc4x3_rc2::IfcComplexPropertyTemplate::UsageName() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcComplexPropertyTemplateTypeEnum::Value > Ifc4x3_rc2::IfcComplexPropertyTemplate::TemplateType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcComplexPropertyTemplateTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc2::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc2::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc2::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPropertyTemplate >::ptr > Ifc4x3_rc2::IfcComplexPropertyTemplate::HasPropertyTemplates() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc2::IfcPropertyTemplate >(); }
-void Ifc4x3_rc2::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcComplexPropertyTemplate::declaration() const { return *IFC4X3_RC2_IfcComplexPropertyTemplate_type; }
@@ -14757,7 +14757,7 @@ Ifc4x3_rc2::IfcCompositeCurveSegment::IfcCompositeCurveSegment(::Ifc4x3_rc2::Ifc
 aggregate_of< ::Ifc4x3_rc2::IfcProfileDef >::ptr Ifc4x3_rc2::IfcCompositeProfileDef::Profiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc2::IfcProfileDef >(); }
 void Ifc4x3_rc2::IfcCompositeProfileDef::setProfiles(aggregate_of< ::Ifc4x3_rc2::IfcProfileDef >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcCompositeProfileDef::Label() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCompositeProfileDef::declaration() const { return *IFC4X3_RC2_IfcCompositeProfileDef_type; }
@@ -14767,7 +14767,7 @@ Ifc4x3_rc2::IfcCompositeProfileDef::IfcCompositeProfileDef(::Ifc4x3_rc2::IfcProf
 
 // Function implementations for IfcCompressor
 boost::optional< ::Ifc4x3_rc2::IfcCompressorTypeEnum::Value > Ifc4x3_rc2::IfcCompressor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCompressorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCompressorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCompressorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCompressor::declaration() const { return *IFC4X3_RC2_IfcCompressor_type; }
@@ -14787,7 +14787,7 @@ Ifc4x3_rc2::IfcCompressorType::IfcCompressorType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCondenser
 boost::optional< ::Ifc4x3_rc2::IfcCondenserTypeEnum::Value > Ifc4x3_rc2::IfcCondenser::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCondenserTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCondenserTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCondenserTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCondenser::declaration() const { return *IFC4X3_RC2_IfcCondenser_type; }
@@ -14847,11 +14847,11 @@ Ifc4x3_rc2::IfcConnectionGeometry::IfcConnectionGeometry() : IfcUtil::IfcBaseEnt
 
 // Function implementations for IfcConnectionPointEccentricity
 boost::optional< double > Ifc4x3_rc2::IfcConnectionPointEccentricity::EccentricityInX() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcConnectionPointEccentricity::EccentricityInY() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcConnectionPointEccentricity::EccentricityInZ() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcConnectionPointEccentricity::declaration() const { return *IFC4X3_RC2_IfcConnectionPointEccentricity_type; }
@@ -14899,17 +14899,17 @@ Ifc4x3_rc2::IfcConnectionVolumeGeometry::IfcConnectionVolumeGeometry(::Ifc4x3_rc
 std::string Ifc4x3_rc2::IfcConstraint::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc2::IfcConstraint::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcConstraint::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc2::IfcConstraintEnum::Value Ifc4x3_rc2::IfcConstraint::ConstraintGrade() const {  return ::Ifc4x3_rc2::IfcConstraintEnum::FromString(*data_->getArgument(2)); }
 void Ifc4x3_rc2::IfcConstraint::setConstraintGrade(::Ifc4x3_rc2::IfcConstraintEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcConstraintEnum::ToString(v)));data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcConstraint::ConstraintSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc2::IfcActorSelect* Ifc4x3_rc2::IfcConstraint::CreatingActor() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc2::IfcActorSelect>(true); }
 void Ifc4x3_rc2::IfcConstraint::setCreatingActor(::Ifc4x3_rc2::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcConstraint::CreationTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcConstraint::UserDefinedGrade() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc2::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc2::IfcConstraint::HasExternalReferences() const { return data_->getInverse(IFC4X3_RC2_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc2::IfcResourceConstraintRelationship::list::ptr Ifc4x3_rc2::IfcConstraint::PropertiesForConstraint() const { return data_->getInverse(IFC4X3_RC2_IfcResourceConstraintRelationship_type, 2)->as<IfcResourceConstraintRelationship>(); }
@@ -14921,7 +14921,7 @@ Ifc4x3_rc2::IfcConstraint::IfcConstraint(std::string v1_Name, boost::optional< s
 
 // Function implementations for IfcConstructionEquipmentResource
 boost::optional< ::Ifc4x3_rc2::IfcConstructionEquipmentResourceTypeEnum::Value > Ifc4x3_rc2::IfcConstructionEquipmentResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcConstructionEquipmentResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcConstructionEquipmentResource::declaration() const { return *IFC4X3_RC2_IfcConstructionEquipmentResource_type; }
@@ -14941,7 +14941,7 @@ Ifc4x3_rc2::IfcConstructionEquipmentResourceType::IfcConstructionEquipmentResour
 
 // Function implementations for IfcConstructionMaterialResource
 boost::optional< ::Ifc4x3_rc2::IfcConstructionMaterialResourceTypeEnum::Value > Ifc4x3_rc2::IfcConstructionMaterialResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcConstructionMaterialResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcConstructionMaterialResource::declaration() const { return *IFC4X3_RC2_IfcConstructionMaterialResource_type; }
@@ -14961,7 +14961,7 @@ Ifc4x3_rc2::IfcConstructionMaterialResourceType::IfcConstructionMaterialResource
 
 // Function implementations for IfcConstructionProductResource
 boost::optional< ::Ifc4x3_rc2::IfcConstructionProductResourceTypeEnum::Value > Ifc4x3_rc2::IfcConstructionProductResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcConstructionProductResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcConstructionProductResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcConstructionProductResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcConstructionProductResource::declaration() const { return *IFC4X3_RC2_IfcConstructionProductResource_type; }
@@ -14983,7 +14983,7 @@ Ifc4x3_rc2::IfcConstructionProductResourceType::IfcConstructionProductResourceTy
 ::Ifc4x3_rc2::IfcResourceTime* Ifc4x3_rc2::IfcConstructionResource::Usage() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc2::IfcResourceTime>(true); }
 void Ifc4x3_rc2::IfcConstructionResource::setUsage(::Ifc4x3_rc2::IfcResourceTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAppliedValue >::ptr > Ifc4x3_rc2::IfcConstructionResource::BaseCosts() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc2::IfcAppliedValue >(); }
-void Ifc4x3_rc2::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc2::IfcPhysicalQuantity* Ifc4x3_rc2::IfcConstructionResource::BaseQuantity() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc2::IfcPhysicalQuantity>(true); }
 void Ifc4x3_rc2::IfcConstructionResource::setBaseQuantity(::Ifc4x3_rc2::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -14995,7 +14995,7 @@ Ifc4x3_rc2::IfcConstructionResource::IfcConstructionResource(std::string v1_Glob
 
 // Function implementations for IfcConstructionResourceType
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAppliedValue >::ptr > Ifc4x3_rc2::IfcConstructionResourceType::BaseCosts() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc2::IfcAppliedValue >(); }
-void Ifc4x3_rc2::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 ::Ifc4x3_rc2::IfcPhysicalQuantity* Ifc4x3_rc2::IfcConstructionResourceType::BaseQuantity() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc2::IfcPhysicalQuantity>(true); }
 void Ifc4x3_rc2::IfcConstructionResourceType::setBaseQuantity(::Ifc4x3_rc2::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -15007,13 +15007,13 @@ Ifc4x3_rc2::IfcConstructionResourceType::IfcConstructionResourceType(std::string
 
 // Function implementations for IfcContext
 boost::optional< std::string > Ifc4x3_rc2::IfcContext::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcContext::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcContext::Phase() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcRepresentationContext >::ptr > Ifc4x3_rc2::IfcContext::RepresentationContexts() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc2::IfcRepresentationContext >(); }
-void Ifc4x3_rc2::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc2::IfcUnitAssignment* Ifc4x3_rc2::IfcContext::UnitsInContext() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc2::IfcUnitAssignment>(true); }
 void Ifc4x3_rc2::IfcContext::setUnitsInContext(::Ifc4x3_rc2::IfcUnitAssignment* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -15038,7 +15038,7 @@ Ifc4x3_rc2::IfcContextDependentUnit::IfcContextDependentUnit(::Ifc4x3_rc2::IfcDi
 
 // Function implementations for IfcControl
 boost::optional< std::string > Ifc4x3_rc2::IfcControl::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc2::IfcRelAssignsToControl::list::ptr Ifc4x3_rc2::IfcControl::Controls() const { return data_->getInverse(IFC4X3_RC2_IfcRelAssignsToControl_type, 6)->as<IfcRelAssignsToControl>(); }
 
@@ -15049,7 +15049,7 @@ Ifc4x3_rc2::IfcControl::IfcControl(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwn
 
 // Function implementations for IfcController
 boost::optional< ::Ifc4x3_rc2::IfcControllerTypeEnum::Value > Ifc4x3_rc2::IfcController::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcControllerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcController::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcControllerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcController::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcControllerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcController::declaration() const { return *IFC4X3_RC2_IfcController_type; }
@@ -15092,7 +15092,7 @@ Ifc4x3_rc2::IfcConversionBasedUnitWithOffset::IfcConversionBasedUnitWithOffset(:
 
 // Function implementations for IfcConveyorSegment
 boost::optional< ::Ifc4x3_rc2::IfcConveyorSegmentTypeEnum::Value > Ifc4x3_rc2::IfcConveyorSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcConveyorSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcConveyorSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcConveyorSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcConveyorSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcConveyorSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcConveyorSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcConveyorSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcConveyorSegment::declaration() const { return *IFC4X3_RC2_IfcConveyorSegment_type; }
@@ -15112,7 +15112,7 @@ Ifc4x3_rc2::IfcConveyorSegmentType::IfcConveyorSegmentType(std::string v1_Global
 
 // Function implementations for IfcCooledBeam
 boost::optional< ::Ifc4x3_rc2::IfcCooledBeamTypeEnum::Value > Ifc4x3_rc2::IfcCooledBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCooledBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCooledBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCooledBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCooledBeam::declaration() const { return *IFC4X3_RC2_IfcCooledBeam_type; }
@@ -15132,7 +15132,7 @@ Ifc4x3_rc2::IfcCooledBeamType::IfcCooledBeamType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCoolingTower
 boost::optional< ::Ifc4x3_rc2::IfcCoolingTowerTypeEnum::Value > Ifc4x3_rc2::IfcCoolingTower::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCoolingTowerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCoolingTowerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCoolingTowerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCoolingTower::declaration() const { return *IFC4X3_RC2_IfcCoolingTower_type; }
@@ -15166,11 +15166,11 @@ Ifc4x3_rc2::IfcCoordinateOperation::IfcCoordinateOperation(::Ifc4x3_rc2::IfcCoor
 std::string Ifc4x3_rc2::IfcCoordinateReferenceSystem::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc2::IfcCoordinateReferenceSystem::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcCoordinateReferenceSystem::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcCoordinateReferenceSystem::GeodeticDatum() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcCoordinateReferenceSystem::VerticalDatum() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 ::Ifc4x3_rc2::IfcCoordinateOperation::list::ptr Ifc4x3_rc2::IfcCoordinateReferenceSystem::HasCoordinateOperation() const { return data_->getInverse(IFC4X3_RC2_IfcCoordinateOperation_type, 0)->as<IfcCoordinateOperation>(); }
 
@@ -15181,11 +15181,11 @@ Ifc4x3_rc2::IfcCoordinateReferenceSystem::IfcCoordinateReferenceSystem(std::stri
 
 // Function implementations for IfcCostItem
 boost::optional< ::Ifc4x3_rc2::IfcCostItemTypeEnum::Value > Ifc4x3_rc2::IfcCostItem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCostItemTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc2::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCostItemTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCostItemTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcCostValue >::ptr > Ifc4x3_rc2::IfcCostItem::CostValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc2::IfcCostValue >(); }
-void Ifc4x3_rc2::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPhysicalQuantity >::ptr > Ifc4x3_rc2::IfcCostItem::CostQuantities() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc2::IfcPhysicalQuantity >(); }
-void Ifc4x3_rc2::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCostItem::declaration() const { return *IFC4X3_RC2_IfcCostItem_type; }
@@ -15195,13 +15195,13 @@ Ifc4x3_rc2::IfcCostItem::IfcCostItem(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcCostSchedule
 boost::optional< ::Ifc4x3_rc2::IfcCostScheduleTypeEnum::Value > Ifc4x3_rc2::IfcCostSchedule::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCostScheduleTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc2::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCostScheduleTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCostScheduleTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcCostSchedule::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcCostSchedule::SubmittedOn() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcCostSchedule::UpdateDate() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCostSchedule::declaration() const { return *IFC4X3_RC2_IfcCostSchedule_type; }
@@ -15219,7 +15219,7 @@ Ifc4x3_rc2::IfcCostValue::IfcCostValue(boost::optional< std::string > v1_Name, b
 
 // Function implementations for IfcCourse
 boost::optional< ::Ifc4x3_rc2::IfcCourseTypeEnum::Value > Ifc4x3_rc2::IfcCourse::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCourseTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCourse::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCourseTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCourseTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCourse::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCourseTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCourseTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCourse::declaration() const { return *IFC4X3_RC2_IfcCourse_type; }
@@ -15239,7 +15239,7 @@ Ifc4x3_rc2::IfcCourseType::IfcCourseType(std::string v1_GlobalId, ::Ifc4x3_rc2::
 
 // Function implementations for IfcCovering
 boost::optional< ::Ifc4x3_rc2::IfcCoveringTypeEnum::Value > Ifc4x3_rc2::IfcCovering::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCoveringTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCoveringTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCoveringTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc2::IfcRelCoversSpaces::list::ptr Ifc4x3_rc2::IfcCovering::CoversSpaces() const { return data_->getInverse(IFC4X3_RC2_IfcRelCoversSpaces_type, 5)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x3_rc2::IfcRelCoversBldgElements::list::ptr Ifc4x3_rc2::IfcCovering::CoversElements() const { return data_->getInverse(IFC4X3_RC2_IfcRelCoversBldgElements_type, 5)->as<IfcRelCoversBldgElements>(); }
@@ -15261,7 +15261,7 @@ Ifc4x3_rc2::IfcCoveringType::IfcCoveringType(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcCrewResource
 boost::optional< ::Ifc4x3_rc2::IfcCrewResourceTypeEnum::Value > Ifc4x3_rc2::IfcCrewResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCrewResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCrewResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCrewResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCrewResource::declaration() const { return *IFC4X3_RC2_IfcCrewResource_type; }
@@ -15307,7 +15307,7 @@ void Ifc4x3_rc2::IfcCurrencyRelationship::setRelatedMonetaryUnit(::Ifc4x3_rc2::I
 double Ifc4x3_rc2::IfcCurrencyRelationship::ExchangeRate() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc2::IfcCurrencyRelationship::setExchangeRate(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcCurrencyRelationship::RateDateTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc2::IfcLibraryInformation* Ifc4x3_rc2::IfcCurrencyRelationship::RateSource() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcLibraryInformation>(true); }
 void Ifc4x3_rc2::IfcCurrencyRelationship::setRateSource(::Ifc4x3_rc2::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -15319,7 +15319,7 @@ Ifc4x3_rc2::IfcCurrencyRelationship::IfcCurrencyRelationship(boost::optional< st
 
 // Function implementations for IfcCurtainWall
 boost::optional< ::Ifc4x3_rc2::IfcCurtainWallTypeEnum::Value > Ifc4x3_rc2::IfcCurtainWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCurtainWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCurtainWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCurtainWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCurtainWall::declaration() const { return *IFC4X3_RC2_IfcCurtainWall_type; }
@@ -15409,7 +15409,7 @@ void Ifc4x3_rc2::IfcCurveStyle::setCurveWidth(::Ifc4x3_rc2::IfcSizeSelect* v) {
 ::Ifc4x3_rc2::IfcColour* Ifc4x3_rc2::IfcCurveStyle::CurveColour() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcColour>(true); }
 void Ifc4x3_rc2::IfcCurveStyle::setCurveColour(::Ifc4x3_rc2::IfcColour* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x3_rc2::IfcCurveStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcCurveStyle::declaration() const { return *IFC4X3_RC2_IfcCurveStyle_type; }
@@ -15419,7 +15419,7 @@ Ifc4x3_rc2::IfcCurveStyle::IfcCurveStyle(boost::optional< std::string > v1_Name,
 
 // Function implementations for IfcCurveStyleFont
 boost::optional< std::string > Ifc4x3_rc2::IfcCurveStyleFont::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc4x3_rc2::IfcCurveStyleFontPattern >::ptr Ifc4x3_rc2::IfcCurveStyleFont::PatternList() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc2::IfcCurveStyleFontPattern >(); }
 void Ifc4x3_rc2::IfcCurveStyleFont::setPatternList(aggregate_of< ::Ifc4x3_rc2::IfcCurveStyleFontPattern >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -15431,7 +15431,7 @@ Ifc4x3_rc2::IfcCurveStyleFont::IfcCurveStyleFont(boost::optional< std::string >
 
 // Function implementations for IfcCurveStyleFontAndScaling
 boost::optional< std::string > Ifc4x3_rc2::IfcCurveStyleFontAndScaling::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc2::IfcCurveStyleFontSelect* Ifc4x3_rc2::IfcCurveStyleFontAndScaling::CurveFont() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc2::IfcCurveStyleFontSelect>(true); }
 void Ifc4x3_rc2::IfcCurveStyleFontAndScaling::setCurveFont(::Ifc4x3_rc2::IfcCurveStyleFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 double Ifc4x3_rc2::IfcCurveStyleFontAndScaling::CurveFontScaling() const {  double v = *data_->getArgument(2); return v; }
@@ -15467,7 +15467,7 @@ Ifc4x3_rc2::IfcCylindricalSurface::IfcCylindricalSurface(::Ifc4x3_rc2::IfcAxis2P
 
 // Function implementations for IfcDamper
 boost::optional< ::Ifc4x3_rc2::IfcDamperTypeEnum::Value > Ifc4x3_rc2::IfcDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDamper::declaration() const { return *IFC4X3_RC2_IfcDamper_type; }
@@ -15507,7 +15507,7 @@ void Ifc4x3_rc2::IfcDerivedProfileDef::setParentProfile(::Ifc4x3_rc2::IfcProfile
 ::Ifc4x3_rc2::IfcCartesianTransformationOperator2D* Ifc4x3_rc2::IfcDerivedProfileDef::Operator() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x3_rc2::IfcDerivedProfileDef::setOperator(::Ifc4x3_rc2::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDerivedProfileDef::Label() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDerivedProfileDef::declaration() const { return *IFC4X3_RC2_IfcDerivedProfileDef_type; }
@@ -15521,7 +15521,7 @@ void Ifc4x3_rc2::IfcDerivedUnit::setElements(aggregate_of< ::Ifc4x3_rc2::IfcDeri
 ::Ifc4x3_rc2::IfcDerivedUnitEnum::Value Ifc4x3_rc2::IfcDerivedUnit::UnitType() const {  return ::Ifc4x3_rc2::IfcDerivedUnitEnum::FromString(*data_->getArgument(1)); }
 void Ifc4x3_rc2::IfcDerivedUnit::setUnitType(::Ifc4x3_rc2::IfcDerivedUnitEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcDerivedUnitEnum::ToString(v)));data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDerivedUnit::UserDefinedType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDerivedUnit::declaration() const { return *IFC4X3_RC2_IfcDerivedUnit_type; }
@@ -15603,7 +15603,7 @@ Ifc4x3_rc2::IfcDirectrixDistanceSweptAreaSolid::IfcDirectrixDistanceSweptAreaSol
 
 // Function implementations for IfcDiscreteAccessory
 boost::optional< ::Ifc4x3_rc2::IfcDiscreteAccessoryTypeEnum::Value > Ifc4x3_rc2::IfcDiscreteAccessory::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDiscreteAccessoryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDiscreteAccessoryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDiscreteAccessoryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDiscreteAccessory::declaration() const { return *IFC4X3_RC2_IfcDiscreteAccessory_type; }
@@ -15623,7 +15623,7 @@ Ifc4x3_rc2::IfcDiscreteAccessoryType::IfcDiscreteAccessoryType(std::string v1_Gl
 
 // Function implementations for IfcDistributionBoard
 boost::optional< ::Ifc4x3_rc2::IfcDistributionBoardTypeEnum::Value > Ifc4x3_rc2::IfcDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDistributionBoard::declaration() const { return *IFC4X3_RC2_IfcDistributionBoard_type; }
@@ -15643,7 +15643,7 @@ Ifc4x3_rc2::IfcDistributionBoardType::IfcDistributionBoardType(std::string v1_Gl
 
 // Function implementations for IfcDistributionChamberElement
 boost::optional< ::Ifc4x3_rc2::IfcDistributionChamberElementTypeEnum::Value > Ifc4x3_rc2::IfcDistributionChamberElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDistributionChamberElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDistributionChamberElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDistributionChamberElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDistributionChamberElement::declaration() const { return *IFC4X3_RC2_IfcDistributionChamberElement_type; }
@@ -15722,11 +15722,11 @@ Ifc4x3_rc2::IfcDistributionFlowElementType::IfcDistributionFlowElementType(std::
 
 // Function implementations for IfcDistributionPort
 boost::optional< ::Ifc4x3_rc2::IfcFlowDirectionEnum::Value > Ifc4x3_rc2::IfcDistributionPort::FlowDirection() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcFlowDirectionEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc2::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x3_rc2::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFlowDirectionEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x3_rc2::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFlowDirectionEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcDistributionPortTypeEnum::Value > Ifc4x3_rc2::IfcDistributionPort::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDistributionPortTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDistributionPortTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDistributionPortTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcDistributionSystemEnum::Value > Ifc4x3_rc2::IfcDistributionPort::SystemType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDistributionSystemEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc2::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x3_rc2::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x3_rc2::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDistributionPort::declaration() const { return *IFC4X3_RC2_IfcDistributionPort_type; }
@@ -15736,9 +15736,9 @@ Ifc4x3_rc2::IfcDistributionPort::IfcDistributionPort(std::string v1_GlobalId, ::
 
 // Function implementations for IfcDistributionSystem
 boost::optional< std::string > Ifc4x3_rc2::IfcDistributionSystem::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcDistributionSystemEnum::Value > Ifc4x3_rc2::IfcDistributionSystem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDistributionSystemEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc2::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDistributionSystem::declaration() const { return *IFC4X3_RC2_IfcDistributionSystem_type; }
@@ -15752,35 +15752,35 @@ void Ifc4x3_rc2::IfcDocumentInformation::setIdentification(std::string v) { {Ifc
 std::string Ifc4x3_rc2::IfcDocumentInformation::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcDocumentInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::Location() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::Purpose() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::IntendedUse() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::Scope() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::Revision() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc2::IfcActorSelect* Ifc4x3_rc2::IfcDocumentInformation::DocumentOwner() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc2::IfcActorSelect>(true); }
 void Ifc4x3_rc2::IfcDocumentInformation::setDocumentOwner(::Ifc4x3_rc2::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc2::IfcDocumentInformation::Editors() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::CreationTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::LastRevisionTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::ElectronicFormat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::ValidFrom() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformation::ValidUntil() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc2::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcDocumentConfidentialityEnum::Value > Ifc4x3_rc2::IfcDocumentInformation::Confidentiality() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDocumentConfidentialityEnum::FromString(*data_->getArgument(15)); }
-void Ifc4x3_rc2::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x3_rc2::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDocumentConfidentialityEnum::ToString(*v)));data_->setArgument(15,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x3_rc2::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDocumentConfidentialityEnum::ToString(*v)));}data_->setArgument(15,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcDocumentStatusEnum::Value > Ifc4x3_rc2::IfcDocumentInformation::Status() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDocumentStatusEnum::FromString(*data_->getArgument(16)); }
-void Ifc4x3_rc2::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x3_rc2::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDocumentStatusEnum::ToString(*v)));data_->setArgument(16,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x3_rc2::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDocumentStatusEnum::ToString(*v)));}data_->setArgument(16,attr);} }
 
 ::Ifc4x3_rc2::IfcRelAssociatesDocument::list::ptr Ifc4x3_rc2::IfcDocumentInformation::DocumentInfoForObjects() const { return data_->getInverse(IFC4X3_RC2_IfcRelAssociatesDocument_type, 5)->as<IfcRelAssociatesDocument>(); }
 ::Ifc4x3_rc2::IfcDocumentReference::list::ptr Ifc4x3_rc2::IfcDocumentInformation::HasDocumentReferences() const { return data_->getInverse(IFC4X3_RC2_IfcDocumentReference_type, 4)->as<IfcDocumentReference>(); }
@@ -15798,7 +15798,7 @@ void Ifc4x3_rc2::IfcDocumentInformationRelationship::setRelatingDocument(::Ifc4x
 aggregate_of< ::Ifc4x3_rc2::IfcDocumentInformation >::ptr Ifc4x3_rc2::IfcDocumentInformationRelationship::RelatedDocuments() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc2::IfcDocumentInformation >(); }
 void Ifc4x3_rc2::IfcDocumentInformationRelationship::setRelatedDocuments(aggregate_of< ::Ifc4x3_rc2::IfcDocumentInformation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentInformationRelationship::RelationshipType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDocumentInformationRelationship::declaration() const { return *IFC4X3_RC2_IfcDocumentInformationRelationship_type; }
@@ -15808,7 +15808,7 @@ Ifc4x3_rc2::IfcDocumentInformationRelationship::IfcDocumentInformationRelationsh
 
 // Function implementations for IfcDocumentReference
 boost::optional< std::string > Ifc4x3_rc2::IfcDocumentReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc2::IfcDocumentInformation* Ifc4x3_rc2::IfcDocumentReference::ReferencedDocument() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc2::IfcDocumentInformation>(true); }
 void Ifc4x3_rc2::IfcDocumentReference::setReferencedDocument(::Ifc4x3_rc2::IfcDocumentInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -15821,15 +15821,15 @@ Ifc4x3_rc2::IfcDocumentReference::IfcDocumentReference(boost::optional< std::str
 
 // Function implementations for IfcDoor
 boost::optional< double > Ifc4x3_rc2::IfcDoor::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoor::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcDoorTypeEnum::Value > Ifc4x3_rc2::IfcDoor::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDoorTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDoorTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDoorTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcDoorTypeOperationEnum::Value > Ifc4x3_rc2::IfcDoor::OperationType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc2::IfcDoor::setOperationType(boost::optional< ::Ifc4x3_rc2::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDoorTypeOperationEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcDoor::setOperationType(boost::optional< ::Ifc4x3_rc2::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDoorTypeOperationEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDoor::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDoor::declaration() const { return *IFC4X3_RC2_IfcDoor_type; }
@@ -15839,31 +15839,31 @@ Ifc4x3_rc2::IfcDoor::IfcDoor(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHist
 
 // Function implementations for IfcDoorLiningProperties
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::ThresholdDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::ThresholdThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::TransomThickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::TransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::LiningOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::ThresholdOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::CasingThickness() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::CasingDepth() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 ::Ifc4x3_rc2::IfcShapeAspect* Ifc4x3_rc2::IfcDoorLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(14)))->as<::Ifc4x3_rc2::IfcShapeAspect>(true); }
 void Ifc4x3_rc2::IfcDoorLiningProperties::setShapeAspectStyle(::Ifc4x3_rc2::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc2::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc2::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDoorLiningProperties::declaration() const { return *IFC4X3_RC2_IfcDoorLiningProperties_type; }
@@ -15873,11 +15873,11 @@ Ifc4x3_rc2::IfcDoorLiningProperties::IfcDoorLiningProperties(std::string v1_Glob
 
 // Function implementations for IfcDoorPanelProperties
 boost::optional< double > Ifc4x3_rc2::IfcDoorPanelProperties::PanelDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc2::IfcDoorPanelOperationEnum::Value Ifc4x3_rc2::IfcDoorPanelProperties::PanelOperation() const {  return ::Ifc4x3_rc2::IfcDoorPanelOperationEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc2::IfcDoorPanelProperties::setPanelOperation(::Ifc4x3_rc2::IfcDoorPanelOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcDoorPanelOperationEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcDoorPanelProperties::PanelWidth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc2::IfcDoorPanelPositionEnum::Value Ifc4x3_rc2::IfcDoorPanelProperties::PanelPosition() const {  return ::Ifc4x3_rc2::IfcDoorPanelPositionEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc2::IfcDoorPanelProperties::setPanelPosition(::Ifc4x3_rc2::IfcDoorPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcDoorPanelPositionEnum::ToString(v)));data_->setArgument(7,attr);} }
 ::Ifc4x3_rc2::IfcShapeAspect* Ifc4x3_rc2::IfcDoorPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc2::IfcShapeAspect>(true); }
@@ -15919,9 +15919,9 @@ void Ifc4x3_rc2::IfcDoorType::setPredefinedType(::Ifc4x3_rc2::IfcDoorTypeEnum::V
 ::Ifc4x3_rc2::IfcDoorTypeOperationEnum::Value Ifc4x3_rc2::IfcDoorType::OperationType() const {  return ::Ifc4x3_rc2::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc2::IfcDoorType::setOperationType(::Ifc4x3_rc2::IfcDoorTypeOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcDoorTypeOperationEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x3_rc2::IfcDoorType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcDoorType::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDoorType::declaration() const { return *IFC4X3_RC2_IfcDoorType_type; }
@@ -15947,7 +15947,7 @@ Ifc4x3_rc2::IfcDraughtingPreDefinedCurveFont::IfcDraughtingPreDefinedCurveFont(s
 
 // Function implementations for IfcDuctFitting
 boost::optional< ::Ifc4x3_rc2::IfcDuctFittingTypeEnum::Value > Ifc4x3_rc2::IfcDuctFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDuctFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDuctFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDuctFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDuctFitting::declaration() const { return *IFC4X3_RC2_IfcDuctFitting_type; }
@@ -15967,7 +15967,7 @@ Ifc4x3_rc2::IfcDuctFittingType::IfcDuctFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcDuctSegment
 boost::optional< ::Ifc4x3_rc2::IfcDuctSegmentTypeEnum::Value > Ifc4x3_rc2::IfcDuctSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDuctSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDuctSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDuctSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDuctSegment::declaration() const { return *IFC4X3_RC2_IfcDuctSegment_type; }
@@ -15987,7 +15987,7 @@ Ifc4x3_rc2::IfcDuctSegmentType::IfcDuctSegmentType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcDuctSilencer
 boost::optional< ::Ifc4x3_rc2::IfcDuctSilencerTypeEnum::Value > Ifc4x3_rc2::IfcDuctSilencer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDuctSilencerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDuctSilencerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDuctSilencerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcDuctSilencer::declaration() const { return *IFC4X3_RC2_IfcDuctSilencer_type; }
@@ -16007,7 +16007,7 @@ Ifc4x3_rc2::IfcDuctSilencerType::IfcDuctSilencerType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcEarthworksCut
 boost::optional< ::Ifc4x3_rc2::IfcEarthworksCutTypeEnum::Value > Ifc4x3_rc2::IfcEarthworksCut::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcEarthworksCutTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcEarthworksCut::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEarthworksCutTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEarthworksCutTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcEarthworksCut::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEarthworksCutTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEarthworksCutTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcEarthworksCut::declaration() const { return *IFC4X3_RC2_IfcEarthworksCut_type; }
@@ -16025,7 +16025,7 @@ Ifc4x3_rc2::IfcEarthworksElement::IfcEarthworksElement(std::string v1_GlobalId,
 
 // Function implementations for IfcEarthworksFill
 boost::optional< ::Ifc4x3_rc2::IfcEarthworksFillTypeEnum::Value > Ifc4x3_rc2::IfcEarthworksFill::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcEarthworksFillTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcEarthworksFill::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEarthworksFillTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEarthworksFillTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcEarthworksFill::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEarthworksFillTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEarthworksFillTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcEarthworksFill::declaration() const { return *IFC4X3_RC2_IfcEarthworksFill_type; }
@@ -16069,7 +16069,7 @@ Ifc4x3_rc2::IfcEdgeLoop::IfcEdgeLoop(aggregate_of< ::Ifc4x3_rc2::IfcOrientedEdge
 
 // Function implementations for IfcElectricAppliance
 boost::optional< ::Ifc4x3_rc2::IfcElectricApplianceTypeEnum::Value > Ifc4x3_rc2::IfcElectricAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcElectricApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcElectricAppliance::declaration() const { return *IFC4X3_RC2_IfcElectricAppliance_type; }
@@ -16089,7 +16089,7 @@ Ifc4x3_rc2::IfcElectricApplianceType::IfcElectricApplianceType(std::string v1_Gl
 
 // Function implementations for IfcElectricDistributionBoard
 boost::optional< ::Ifc4x3_rc2::IfcElectricDistributionBoardTypeEnum::Value > Ifc4x3_rc2::IfcElectricDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcElectricDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcElectricDistributionBoard::declaration() const { return *IFC4X3_RC2_IfcElectricDistributionBoard_type; }
@@ -16109,7 +16109,7 @@ Ifc4x3_rc2::IfcElectricDistributionBoardType::IfcElectricDistributionBoardType(s
 
 // Function implementations for IfcElectricFlowStorageDevice
 boost::optional< ::Ifc4x3_rc2::IfcElectricFlowStorageDeviceTypeEnum::Value > Ifc4x3_rc2::IfcElectricFlowStorageDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcElectricFlowStorageDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcElectricFlowStorageDevice::declaration() const { return *IFC4X3_RC2_IfcElectricFlowStorageDevice_type; }
@@ -16129,7 +16129,7 @@ Ifc4x3_rc2::IfcElectricFlowStorageDeviceType::IfcElectricFlowStorageDeviceType(s
 
 // Function implementations for IfcElectricFlowTreatmentDevice
 boost::optional< ::Ifc4x3_rc2::IfcElectricFlowTreatmentDeviceTypeEnum::Value > Ifc4x3_rc2::IfcElectricFlowTreatmentDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcElectricFlowTreatmentDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcElectricFlowTreatmentDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricFlowTreatmentDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricFlowTreatmentDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcElectricFlowTreatmentDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricFlowTreatmentDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricFlowTreatmentDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcElectricFlowTreatmentDevice::declaration() const { return *IFC4X3_RC2_IfcElectricFlowTreatmentDevice_type; }
@@ -16149,7 +16149,7 @@ Ifc4x3_rc2::IfcElectricFlowTreatmentDeviceType::IfcElectricFlowTreatmentDeviceTy
 
 // Function implementations for IfcElectricGenerator
 boost::optional< ::Ifc4x3_rc2::IfcElectricGeneratorTypeEnum::Value > Ifc4x3_rc2::IfcElectricGenerator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcElectricGeneratorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricGeneratorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricGeneratorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcElectricGenerator::declaration() const { return *IFC4X3_RC2_IfcElectricGenerator_type; }
@@ -16169,7 +16169,7 @@ Ifc4x3_rc2::IfcElectricGeneratorType::IfcElectricGeneratorType(std::string v1_Gl
 
 // Function implementations for IfcElectricMotor
 boost::optional< ::Ifc4x3_rc2::IfcElectricMotorTypeEnum::Value > Ifc4x3_rc2::IfcElectricMotor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcElectricMotorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricMotorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricMotorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcElectricMotor::declaration() const { return *IFC4X3_RC2_IfcElectricMotor_type; }
@@ -16189,7 +16189,7 @@ Ifc4x3_rc2::IfcElectricMotorType::IfcElectricMotorType(std::string v1_GlobalId,
 
 // Function implementations for IfcElectricTimeControl
 boost::optional< ::Ifc4x3_rc2::IfcElectricTimeControlTypeEnum::Value > Ifc4x3_rc2::IfcElectricTimeControl::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcElectricTimeControlTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricTimeControlTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElectricTimeControlTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcElectricTimeControl::declaration() const { return *IFC4X3_RC2_IfcElectricTimeControl_type; }
@@ -16209,7 +16209,7 @@ Ifc4x3_rc2::IfcElectricTimeControlType::IfcElectricTimeControlType(std::string v
 
 // Function implementations for IfcElement
 boost::optional< std::string > Ifc4x3_rc2::IfcElement::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc2::IfcRelFillsElement::list::ptr Ifc4x3_rc2::IfcElement::FillsVoids() const { return data_->getInverse(IFC4X3_RC2_IfcRelFillsElement_type, 5)->as<IfcRelFillsElement>(); }
 ::Ifc4x3_rc2::IfcRelConnectsElements::list::ptr Ifc4x3_rc2::IfcElement::ConnectedTo() const { return data_->getInverse(IFC4X3_RC2_IfcRelConnectsElements_type, 5)->as<IfcRelConnectsElements>(); }
@@ -16230,9 +16230,9 @@ Ifc4x3_rc2::IfcElement::IfcElement(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwn
 
 // Function implementations for IfcElementAssembly
 boost::optional< ::Ifc4x3_rc2::IfcAssemblyPlaceEnum::Value > Ifc4x3_rc2::IfcElementAssembly::AssemblyPlace() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x3_rc2::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAssemblyPlaceEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x3_rc2::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcAssemblyPlaceEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcElementAssemblyTypeEnum::Value > Ifc4x3_rc2::IfcElementAssembly::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcElementAssemblyTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc2::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElementAssemblyTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElementAssemblyTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcElementAssembly::declaration() const { return *IFC4X3_RC2_IfcElementAssembly_type; }
@@ -16268,7 +16268,7 @@ Ifc4x3_rc2::IfcElementComponentType::IfcElementComponentType(std::string v1_Glob
 
 // Function implementations for IfcElementQuantity
 boost::optional< std::string > Ifc4x3_rc2::IfcElementQuantity::MethodOfMeasurement() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x3_rc2::IfcPhysicalQuantity >::ptr Ifc4x3_rc2::IfcElementQuantity::Quantities() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc2::IfcPhysicalQuantity >(); }
 void Ifc4x3_rc2::IfcElementQuantity::setQuantities(aggregate_of< ::Ifc4x3_rc2::IfcPhysicalQuantity >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -16280,7 +16280,7 @@ Ifc4x3_rc2::IfcElementQuantity::IfcElementQuantity(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcElementType
 boost::optional< std::string > Ifc4x3_rc2::IfcElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcElementType::declaration() const { return *IFC4X3_RC2_IfcElementType_type; }
@@ -16340,7 +16340,7 @@ Ifc4x3_rc2::IfcEnergyConversionDeviceType::IfcEnergyConversionDeviceType(std::st
 
 // Function implementations for IfcEngine
 boost::optional< ::Ifc4x3_rc2::IfcEngineTypeEnum::Value > Ifc4x3_rc2::IfcEngine::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcEngineTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEngineTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEngineTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcEngine::declaration() const { return *IFC4X3_RC2_IfcEngine_type; }
@@ -16360,7 +16360,7 @@ Ifc4x3_rc2::IfcEngineType::IfcEngineType(std::string v1_GlobalId, ::Ifc4x3_rc2::
 
 // Function implementations for IfcEvaporativeCooler
 boost::optional< ::Ifc4x3_rc2::IfcEvaporativeCoolerTypeEnum::Value > Ifc4x3_rc2::IfcEvaporativeCooler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcEvaporativeCoolerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEvaporativeCoolerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEvaporativeCoolerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcEvaporativeCooler::declaration() const { return *IFC4X3_RC2_IfcEvaporativeCooler_type; }
@@ -16380,7 +16380,7 @@ Ifc4x3_rc2::IfcEvaporativeCoolerType::IfcEvaporativeCoolerType(std::string v1_Gl
 
 // Function implementations for IfcEvaporator
 boost::optional< ::Ifc4x3_rc2::IfcEvaporatorTypeEnum::Value > Ifc4x3_rc2::IfcEvaporator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcEvaporatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEvaporatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEvaporatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcEvaporator::declaration() const { return *IFC4X3_RC2_IfcEvaporator_type; }
@@ -16400,11 +16400,11 @@ Ifc4x3_rc2::IfcEvaporatorType::IfcEvaporatorType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcEvent
 boost::optional< ::Ifc4x3_rc2::IfcEventTypeEnum::Value > Ifc4x3_rc2::IfcEvent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcEventTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc2::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEventTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEventTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcEventTriggerTypeEnum::Value > Ifc4x3_rc2::IfcEvent::EventTriggerType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x3_rc2::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEventTriggerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x3_rc2::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcEventTriggerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcEvent::UserDefinedEventTriggerType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 ::Ifc4x3_rc2::IfcEventTime* Ifc4x3_rc2::IfcEvent::EventOccurenceTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc2::IfcEventTime>(true); }
 void Ifc4x3_rc2::IfcEvent::setEventOccurenceTime(::Ifc4x3_rc2::IfcEventTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -16416,13 +16416,13 @@ Ifc4x3_rc2::IfcEvent::IfcEvent(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHi
 
 // Function implementations for IfcEventTime
 boost::optional< std::string > Ifc4x3_rc2::IfcEventTime::ActualDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcEventTime::EarlyDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcEventTime::LateDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcEventTime::ScheduleDate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcEventTime::declaration() const { return *IFC4X3_RC2_IfcEventTime_type; }
@@ -16436,7 +16436,7 @@ void Ifc4x3_rc2::IfcEventType::setPredefinedType(::Ifc4x3_rc2::IfcEventTypeEnum:
 ::Ifc4x3_rc2::IfcEventTriggerTypeEnum::Value Ifc4x3_rc2::IfcEventType::EventTriggerType() const {  return ::Ifc4x3_rc2::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc2::IfcEventType::setEventTriggerType(::Ifc4x3_rc2::IfcEventTriggerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcEventTriggerTypeEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcEventType::UserDefinedEventTriggerType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcEventType::declaration() const { return *IFC4X3_RC2_IfcEventType_type; }
@@ -16446,9 +16446,9 @@ Ifc4x3_rc2::IfcEventType::IfcEventType(std::string v1_GlobalId, ::Ifc4x3_rc2::If
 
 // Function implementations for IfcExtendedProperties
 boost::optional< std::string > Ifc4x3_rc2::IfcExtendedProperties::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcExtendedProperties::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc2::IfcProperty >::ptr Ifc4x3_rc2::IfcExtendedProperties::Properties() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc2::IfcProperty >(); }
 void Ifc4x3_rc2::IfcExtendedProperties::setProperties(aggregate_of< ::Ifc4x3_rc2::IfcProperty >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -16468,11 +16468,11 @@ Ifc4x3_rc2::IfcExternalInformation::IfcExternalInformation() : IfcUtil::IfcBaseE
 
 // Function implementations for IfcExternalReference
 boost::optional< std::string > Ifc4x3_rc2::IfcExternalReference::Location() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcExternalReference::Identification() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcExternalReference::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc2::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc2::IfcExternalReference::ExternalReferenceForResources() const { return data_->getInverse(IFC4X3_RC2_IfcExternalReferenceRelationship_type, 2)->as<IfcExternalReferenceRelationship>(); }
 
@@ -16495,7 +16495,7 @@ Ifc4x3_rc2::IfcExternalReferenceRelationship::IfcExternalReferenceRelationship(b
 
 // Function implementations for IfcExternalSpatialElement
 boost::optional< ::Ifc4x3_rc2::IfcExternalSpatialElementTypeEnum::Value > Ifc4x3_rc2::IfcExternalSpatialElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcExternalSpatialElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcExternalSpatialElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcExternalSpatialElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc2::IfcRelSpaceBoundary::list::ptr Ifc4x3_rc2::IfcExternalSpatialElement::BoundedBy() const { return data_->getInverse(IFC4X3_RC2_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
 
@@ -16651,17 +16651,17 @@ Ifc4x3_rc2::IfcFacilityPart::IfcFacilityPart(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcFailureConnectionCondition
 boost::optional< double > Ifc4x3_rc2::IfcFailureConnectionCondition::TensionFailureX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcFailureConnectionCondition::TensionFailureY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcFailureConnectionCondition::TensionFailureZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcFailureConnectionCondition::CompressionFailureX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcFailureConnectionCondition::CompressionFailureY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcFailureConnectionCondition::CompressionFailureZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFailureConnectionCondition::declaration() const { return *IFC4X3_RC2_IfcFailureConnectionCondition_type; }
@@ -16671,7 +16671,7 @@ Ifc4x3_rc2::IfcFailureConnectionCondition::IfcFailureConnectionCondition(boost::
 
 // Function implementations for IfcFan
 boost::optional< ::Ifc4x3_rc2::IfcFanTypeEnum::Value > Ifc4x3_rc2::IfcFan::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcFanTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcFan::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFanTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcFan::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFanTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFan::declaration() const { return *IFC4X3_RC2_IfcFan_type; }
@@ -16691,7 +16691,7 @@ Ifc4x3_rc2::IfcFanType::IfcFanType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwn
 
 // Function implementations for IfcFastener
 boost::optional< ::Ifc4x3_rc2::IfcFastenerTypeEnum::Value > Ifc4x3_rc2::IfcFastener::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcFastenerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFastenerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFastenerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFastener::declaration() const { return *IFC4X3_RC2_IfcFastener_type; }
@@ -16739,7 +16739,7 @@ Ifc4x3_rc2::IfcFeatureElementSubtraction::IfcFeatureElementSubtraction(std::stri
 aggregate_of_instance::ptr Ifc4x3_rc2::IfcFillAreaStyle::FillStyles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcFillAreaStyle::setFillStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc2::IfcFillAreaStyle::ModelOrDraughting() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcFillAreaStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcFillAreaStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFillAreaStyle::declaration() const { return *IFC4X3_RC2_IfcFillAreaStyle_type; }
@@ -16781,7 +16781,7 @@ Ifc4x3_rc2::IfcFillAreaStyleTiles::IfcFillAreaStyleTiles(aggregate_of< ::Ifc4x3_
 
 // Function implementations for IfcFilter
 boost::optional< ::Ifc4x3_rc2::IfcFilterTypeEnum::Value > Ifc4x3_rc2::IfcFilter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcFilterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFilterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFilterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFilter::declaration() const { return *IFC4X3_RC2_IfcFilter_type; }
@@ -16801,7 +16801,7 @@ Ifc4x3_rc2::IfcFilterType::IfcFilterType(std::string v1_GlobalId, ::Ifc4x3_rc2::
 
 // Function implementations for IfcFireSuppressionTerminal
 boost::optional< ::Ifc4x3_rc2::IfcFireSuppressionTerminalTypeEnum::Value > Ifc4x3_rc2::IfcFireSuppressionTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcFireSuppressionTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFireSuppressionTerminal::declaration() const { return *IFC4X3_RC2_IfcFireSuppressionTerminal_type; }
@@ -16863,7 +16863,7 @@ Ifc4x3_rc2::IfcFlowFittingType::IfcFlowFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcFlowInstrument
 boost::optional< ::Ifc4x3_rc2::IfcFlowInstrumentTypeEnum::Value > Ifc4x3_rc2::IfcFlowInstrument::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcFlowInstrumentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFlowInstrumentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFlowInstrumentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFlowInstrument::declaration() const { return *IFC4X3_RC2_IfcFlowInstrument_type; }
@@ -16883,7 +16883,7 @@ Ifc4x3_rc2::IfcFlowInstrumentType::IfcFlowInstrumentType(std::string v1_GlobalId
 
 // Function implementations for IfcFlowMeter
 boost::optional< ::Ifc4x3_rc2::IfcFlowMeterTypeEnum::Value > Ifc4x3_rc2::IfcFlowMeter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcFlowMeterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFlowMeterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFlowMeterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFlowMeter::declaration() const { return *IFC4X3_RC2_IfcFlowMeter_type; }
@@ -16983,7 +16983,7 @@ Ifc4x3_rc2::IfcFlowTreatmentDeviceType::IfcFlowTreatmentDeviceType(std::string v
 
 // Function implementations for IfcFooting
 boost::optional< ::Ifc4x3_rc2::IfcFootingTypeEnum::Value > Ifc4x3_rc2::IfcFooting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcFootingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFootingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFootingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFooting::declaration() const { return *IFC4X3_RC2_IfcFooting_type; }
@@ -17019,7 +17019,7 @@ Ifc4x3_rc2::IfcFurnishingElementType::IfcFurnishingElementType(std::string v1_Gl
 
 // Function implementations for IfcFurniture
 boost::optional< ::Ifc4x3_rc2::IfcFurnitureTypeEnum::Value > Ifc4x3_rc2::IfcFurniture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcFurnitureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFurniture::declaration() const { return *IFC4X3_RC2_IfcFurniture_type; }
@@ -17031,7 +17031,7 @@ Ifc4x3_rc2::IfcFurniture::IfcFurniture(std::string v1_GlobalId, ::Ifc4x3_rc2::If
 ::Ifc4x3_rc2::IfcAssemblyPlaceEnum::Value Ifc4x3_rc2::IfcFurnitureType::AssemblyPlace() const {  return ::Ifc4x3_rc2::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc2::IfcFurnitureType::setAssemblyPlace(::Ifc4x3_rc2::IfcAssemblyPlaceEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcAssemblyPlaceEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcFurnitureTypeEnum::Value > Ifc4x3_rc2::IfcFurnitureType::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcFurnitureTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcFurnitureType::declaration() const { return *IFC4X3_RC2_IfcFurnitureType_type; }
@@ -17041,7 +17041,7 @@ Ifc4x3_rc2::IfcFurnitureType::IfcFurnitureType(std::string v1_GlobalId, ::Ifc4x3
 
 // Function implementations for IfcGeographicElement
 boost::optional< ::Ifc4x3_rc2::IfcGeographicElementTypeEnum::Value > Ifc4x3_rc2::IfcGeographicElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcGeographicElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcGeographicElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcGeographicElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcGeographicElement::declaration() const { return *IFC4X3_RC2_IfcGeographicElement_type; }
@@ -17071,7 +17071,7 @@ Ifc4x3_rc2::IfcGeometricCurveSet::IfcGeometricCurveSet(aggregate_of_instance::pt
 int Ifc4x3_rc2::IfcGeometricRepresentationContext::CoordinateSpaceDimension() const {  int v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc2::IfcGeometricRepresentationContext::setCoordinateSpaceDimension(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcGeometricRepresentationContext::Precision() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc2::IfcAxis2Placement* Ifc4x3_rc2::IfcGeometricRepresentationContext::WorldCoordinateSystem() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc2::IfcAxis2Placement>(true); }
 void Ifc4x3_rc2::IfcGeometricRepresentationContext::setWorldCoordinateSystem(::Ifc4x3_rc2::IfcAxis2Placement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 ::Ifc4x3_rc2::IfcDirection* Ifc4x3_rc2::IfcGeometricRepresentationContext::TrueNorth() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc2::IfcDirection>(true); }
@@ -17097,11 +17097,11 @@ Ifc4x3_rc2::IfcGeometricRepresentationItem::IfcGeometricRepresentationItem() : I
 ::Ifc4x3_rc2::IfcGeometricRepresentationContext* Ifc4x3_rc2::IfcGeometricRepresentationSubContext::ParentContext() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcGeometricRepresentationContext>(true); }
 void Ifc4x3_rc2::IfcGeometricRepresentationSubContext::setParentContext(::Ifc4x3_rc2::IfcGeometricRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcGeometricRepresentationSubContext::TargetScale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc2::IfcGeometricProjectionEnum::Value Ifc4x3_rc2::IfcGeometricRepresentationSubContext::TargetView() const {  return ::Ifc4x3_rc2::IfcGeometricProjectionEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc2::IfcGeometricRepresentationSubContext::setTargetView(::Ifc4x3_rc2::IfcGeometricProjectionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcGeometricProjectionEnum::ToString(v)));data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcGeometricRepresentationSubContext::UserDefinedTargetView() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcGeometricRepresentationSubContext::declaration() const { return *IFC4X3_RC2_IfcGeometricRepresentationSubContext_type; }
@@ -17179,9 +17179,9 @@ void Ifc4x3_rc2::IfcGrid::setUAxes(aggregate_of< ::Ifc4x3_rc2::IfcGridAxis >::pt
 aggregate_of< ::Ifc4x3_rc2::IfcGridAxis >::ptr Ifc4x3_rc2::IfcGrid::VAxes() const {  aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc2::IfcGridAxis >(); }
 void Ifc4x3_rc2::IfcGrid::setVAxes(aggregate_of< ::Ifc4x3_rc2::IfcGridAxis >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcGridAxis >::ptr > Ifc4x3_rc2::IfcGrid::WAxes() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc2::IfcGridAxis >(); }
-void Ifc4x3_rc2::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcGridTypeEnum::Value > Ifc4x3_rc2::IfcGrid::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcGridTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcGridTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcGridTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcGrid::declaration() const { return *IFC4X3_RC2_IfcGrid_type; }
@@ -17191,7 +17191,7 @@ Ifc4x3_rc2::IfcGrid::IfcGrid(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHist
 
 // Function implementations for IfcGridAxis
 boost::optional< std::string > Ifc4x3_rc2::IfcGridAxis::AxisTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc2::IfcCurve* Ifc4x3_rc2::IfcGridAxis::AxisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc2::IfcCurve>(true); }
 void Ifc4x3_rc2::IfcGridAxis::setAxisCurve(::Ifc4x3_rc2::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 bool Ifc4x3_rc2::IfcGridAxis::SameSense() const {  bool v = *data_->getArgument(2); return v; }
@@ -17242,7 +17242,7 @@ Ifc4x3_rc2::IfcHalfSpaceSolid::IfcHalfSpaceSolid(::Ifc4x3_rc2::IfcSurface* v1_Ba
 
 // Function implementations for IfcHeatExchanger
 boost::optional< ::Ifc4x3_rc2::IfcHeatExchangerTypeEnum::Value > Ifc4x3_rc2::IfcHeatExchanger::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcHeatExchangerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcHeatExchangerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcHeatExchangerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcHeatExchanger::declaration() const { return *IFC4X3_RC2_IfcHeatExchanger_type; }
@@ -17262,7 +17262,7 @@ Ifc4x3_rc2::IfcHeatExchangerType::IfcHeatExchangerType(std::string v1_GlobalId,
 
 // Function implementations for IfcHumidifier
 boost::optional< ::Ifc4x3_rc2::IfcHumidifierTypeEnum::Value > Ifc4x3_rc2::IfcHumidifier::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcHumidifierTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcHumidifierTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcHumidifierTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcHumidifier::declaration() const { return *IFC4X3_RC2_IfcHumidifier_type; }
@@ -17290,11 +17290,11 @@ void Ifc4x3_rc2::IfcIShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc2::IfcIShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcIShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcIShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcIShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcIShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcIShapeProfileDef::declaration() const { return *IFC4X3_RC2_IfcIShapeProfileDef_type; }
@@ -17334,7 +17334,7 @@ Ifc4x3_rc2::IfcImpactProtectionDeviceType::IfcImpactProtectionDeviceType(std::st
 
 // Function implementations for IfcInclinedReferenceSweptAreaSolid
 boost::optional< bool > Ifc4x3_rc2::IfcInclinedReferenceSweptAreaSolid::FixedAxisVertical() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } bool v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcInclinedReferenceSweptAreaSolid::setFixedAxisVertical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcInclinedReferenceSweptAreaSolid::setFixedAxisVertical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc2::IfcAxisLateralInclination* Ifc4x3_rc2::IfcInclinedReferenceSweptAreaSolid::Inclinating() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcAxisLateralInclination>(true); }
 void Ifc4x3_rc2::IfcInclinedReferenceSweptAreaSolid::setInclinating(::Ifc4x3_rc2::IfcAxisLateralInclination* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -17348,7 +17348,7 @@ Ifc4x3_rc2::IfcInclinedReferenceSweptAreaSolid::IfcInclinedReferenceSweptAreaSol
 ::Ifc4x3_rc2::IfcTessellatedFaceSet* Ifc4x3_rc2::IfcIndexedColourMap::MappedTo() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc2::IfcTessellatedFaceSet>(true); }
 void Ifc4x3_rc2::IfcIndexedColourMap::setMappedTo(::Ifc4x3_rc2::IfcTessellatedFaceSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcIndexedColourMap::Opacity() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc2::IfcColourRgbList* Ifc4x3_rc2::IfcIndexedColourMap::Colours() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc2::IfcColourRgbList>(true); }
 void Ifc4x3_rc2::IfcIndexedColourMap::setColours(::Ifc4x3_rc2::IfcColourRgbList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::vector< int > /*[1:?]*/ Ifc4x3_rc2::IfcIndexedColourMap::ColourIndex() const {  std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
@@ -17364,9 +17364,9 @@ Ifc4x3_rc2::IfcIndexedColourMap::IfcIndexedColourMap(::Ifc4x3_rc2::IfcTessellate
 ::Ifc4x3_rc2::IfcCartesianPointList* Ifc4x3_rc2::IfcIndexedPolyCurve::Points() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc2::IfcCartesianPointList>(true); }
 void Ifc4x3_rc2::IfcIndexedPolyCurve::setPoints(::Ifc4x3_rc2::IfcCartesianPointList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc2::IfcIndexedPolyCurve::Segments() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc2::IfcIndexedPolyCurve::SelfIntersect() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcIndexedPolyCurve::declaration() const { return *IFC4X3_RC2_IfcIndexedPolyCurve_type; }
@@ -17409,7 +17409,7 @@ Ifc4x3_rc2::IfcIndexedTextureMap::IfcIndexedTextureMap(aggregate_of< ::Ifc4x3_rc
 
 // Function implementations for IfcIndexedTriangleTextureMap
 boost::optional< std::vector< std::vector< int > > > Ifc4x3_rc2::IfcIndexedTriangleTextureMap::TexCoordIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcIndexedTriangleTextureMap::declaration() const { return *IFC4X3_RC2_IfcIndexedTriangleTextureMap_type; }
@@ -17419,7 +17419,7 @@ Ifc4x3_rc2::IfcIndexedTriangleTextureMap::IfcIndexedTriangleTextureMap(aggregate
 
 // Function implementations for IfcInterceptor
 boost::optional< ::Ifc4x3_rc2::IfcInterceptorTypeEnum::Value > Ifc4x3_rc2::IfcInterceptor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcInterceptorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcInterceptorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcInterceptorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcInterceptor::declaration() const { return *IFC4X3_RC2_IfcInterceptor_type; }
@@ -17447,13 +17447,13 @@ Ifc4x3_rc2::IfcIntersectionCurve::IfcIntersectionCurve(::Ifc4x3_rc2::IfcCurve* v
 
 // Function implementations for IfcInventory
 boost::optional< ::Ifc4x3_rc2::IfcInventoryTypeEnum::Value > Ifc4x3_rc2::IfcInventory::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcInventoryTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc2::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcInventoryTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcInventoryTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc2::IfcActorSelect* Ifc4x3_rc2::IfcInventory::Jurisdiction() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcActorSelect>(true); }
 void Ifc4x3_rc2::IfcInventory::setJurisdiction(::Ifc4x3_rc2::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPerson >::ptr > Ifc4x3_rc2::IfcInventory::ResponsiblePersons() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc2::IfcPerson >(); }
-void Ifc4x3_rc2::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcInventory::LastUpdateDate() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc2::IfcCostValue* Ifc4x3_rc2::IfcInventory::CurrentValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc2::IfcCostValue>(true); }
 void Ifc4x3_rc2::IfcInventory::setCurrentValue(::Ifc4x3_rc2::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x3_rc2::IfcCostValue* Ifc4x3_rc2::IfcInventory::OriginalValue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc2::IfcCostValue>(true); }
@@ -17489,7 +17489,7 @@ Ifc4x3_rc2::IfcIrregularTimeSeriesValue::IfcIrregularTimeSeriesValue(std::string
 
 // Function implementations for IfcJunctionBox
 boost::optional< ::Ifc4x3_rc2::IfcJunctionBoxTypeEnum::Value > Ifc4x3_rc2::IfcJunctionBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcJunctionBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcJunctionBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcJunctionBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcJunctionBox::declaration() const { return *IFC4X3_RC2_IfcJunctionBox_type; }
@@ -17531,15 +17531,15 @@ Ifc4x3_rc2::IfcKerbType::IfcKerbType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 double Ifc4x3_rc2::IfcLShapeProfileDef::Depth() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcLShapeProfileDef::setDepth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcLShapeProfileDef::Width() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 double Ifc4x3_rc2::IfcLShapeProfileDef::Thickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc2::IfcLShapeProfileDef::setThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcLShapeProfileDef::FilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcLShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcLShapeProfileDef::LegSlope() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcLShapeProfileDef::declaration() const { return *IFC4X3_RC2_IfcLShapeProfileDef_type; }
@@ -17549,7 +17549,7 @@ Ifc4x3_rc2::IfcLShapeProfileDef::IfcLShapeProfileDef(::Ifc4x3_rc2::IfcProfileTyp
 
 // Function implementations for IfcLaborResource
 boost::optional< ::Ifc4x3_rc2::IfcLaborResourceTypeEnum::Value > Ifc4x3_rc2::IfcLaborResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcLaborResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcLaborResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcLaborResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcLaborResource::declaration() const { return *IFC4X3_RC2_IfcLaborResource_type; }
@@ -17581,7 +17581,7 @@ Ifc4x3_rc2::IfcLagTime::IfcLagTime(boost::optional< std::string > v1_Name, boost
 
 // Function implementations for IfcLamp
 boost::optional< ::Ifc4x3_rc2::IfcLampTypeEnum::Value > Ifc4x3_rc2::IfcLamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcLampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcLampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcLampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcLamp::declaration() const { return *IFC4X3_RC2_IfcLamp_type; }
@@ -17603,15 +17603,15 @@ Ifc4x3_rc2::IfcLampType::IfcLampType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 std::string Ifc4x3_rc2::IfcLibraryInformation::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc2::IfcLibraryInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcLibraryInformation::Version() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc2::IfcActorSelect* Ifc4x3_rc2::IfcLibraryInformation::Publisher() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc2::IfcActorSelect>(true); }
 void Ifc4x3_rc2::IfcLibraryInformation::setPublisher(::Ifc4x3_rc2::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcLibraryInformation::VersionDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcLibraryInformation::Location() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcLibraryInformation::Description() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc2::IfcRelAssociatesLibrary::list::ptr Ifc4x3_rc2::IfcLibraryInformation::LibraryInfoForObjects() const { return data_->getInverse(IFC4X3_RC2_IfcRelAssociatesLibrary_type, 5)->as<IfcRelAssociatesLibrary>(); }
 ::Ifc4x3_rc2::IfcLibraryReference::list::ptr Ifc4x3_rc2::IfcLibraryInformation::HasLibraryReferences() const { return data_->getInverse(IFC4X3_RC2_IfcLibraryReference_type, 5)->as<IfcLibraryReference>(); }
@@ -17623,9 +17623,9 @@ Ifc4x3_rc2::IfcLibraryInformation::IfcLibraryInformation(std::string v1_Name, bo
 
 // Function implementations for IfcLibraryReference
 boost::optional< std::string > Ifc4x3_rc2::IfcLibraryReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcLibraryReference::Language() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc2::IfcLibraryInformation* Ifc4x3_rc2::IfcLibraryReference::ReferencedLibrary() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc2::IfcLibraryInformation>(true); }
 void Ifc4x3_rc2::IfcLibraryReference::setReferencedLibrary(::Ifc4x3_rc2::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -17652,7 +17652,7 @@ Ifc4x3_rc2::IfcLightDistributionData::IfcLightDistributionData(double v1_MainPla
 
 // Function implementations for IfcLightFixture
 boost::optional< ::Ifc4x3_rc2::IfcLightFixtureTypeEnum::Value > Ifc4x3_rc2::IfcLightFixture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcLightFixtureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcLightFixtureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcLightFixtureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcLightFixture::declaration() const { return *IFC4X3_RC2_IfcLightFixture_type; }
@@ -17684,13 +17684,13 @@ Ifc4x3_rc2::IfcLightIntensityDistribution::IfcLightIntensityDistribution(::Ifc4x
 
 // Function implementations for IfcLightSource
 boost::optional< std::string > Ifc4x3_rc2::IfcLightSource::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc2::IfcColourRgb* Ifc4x3_rc2::IfcLightSource::LightColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc2::IfcColourRgb>(true); }
 void Ifc4x3_rc2::IfcLightSource::setLightColour(::Ifc4x3_rc2::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcLightSource::AmbientIntensity() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcLightSource::Intensity() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcLightSource::declaration() const { return *IFC4X3_RC2_IfcLightSource_type; }
@@ -17758,7 +17758,7 @@ Ifc4x3_rc2::IfcLightSourcePositional::IfcLightSourcePositional(boost::optional<
 ::Ifc4x3_rc2::IfcDirection* Ifc4x3_rc2::IfcLightSourceSpot::Orientation() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc2::IfcDirection>(true); }
 void Ifc4x3_rc2::IfcLightSourceSpot::setOrientation(::Ifc4x3_rc2::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcLightSourceSpot::ConcentrationExponent() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 double Ifc4x3_rc2::IfcLightSourceSpot::SpreadAngle() const {  double v = *data_->getArgument(11); return v; }
 void Ifc4x3_rc2::IfcLightSourceSpot::setSpreadAngle(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 double Ifc4x3_rc2::IfcLightSourceSpot::BeamWidthAngle() const {  double v = *data_->getArgument(12); return v; }
@@ -17858,7 +17858,7 @@ Ifc4x3_rc2::IfcLinearSpanPlacement::IfcLinearSpanPlacement(::Ifc4x3_rc2::IfcObje
 
 // Function implementations for IfcLiquidTerminal
 boost::optional< ::Ifc4x3_rc2::IfcLiquidTerminalTypeEnum::Value > Ifc4x3_rc2::IfcLiquidTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcLiquidTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcLiquidTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcLiquidTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcLiquidTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcLiquidTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcLiquidTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcLiquidTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcLiquidTerminal::declaration() const { return *IFC4X3_RC2_IfcLiquidTerminal_type; }
@@ -17912,11 +17912,11 @@ void Ifc4x3_rc2::IfcMapConversion::setNorthings(double v) { {IfcWrite::IfcWriteA
 double Ifc4x3_rc2::IfcMapConversion::OrthogonalHeight() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc2::IfcMapConversion::setOrthogonalHeight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcMapConversion::XAxisAbscissa() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcMapConversion::XAxisOrdinate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcMapConversion::Scale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMapConversion::declaration() const { return *IFC4X3_RC2_IfcMapConversion_type; }
@@ -17950,9 +17950,9 @@ Ifc4x3_rc2::IfcMarineFacility::IfcMarineFacility(std::string v1_GlobalId, ::Ifc4
 std::string Ifc4x3_rc2::IfcMaterial::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc2::IfcMaterial::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterial::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterial::Category() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc2::IfcMaterialDefinitionRepresentation::list::ptr Ifc4x3_rc2::IfcMaterial::HasRepresentation() const { return data_->getInverse(IFC4X3_RC2_IfcMaterialDefinitionRepresentation_type, 3)->as<IfcMaterialDefinitionRepresentation>(); }
 ::Ifc4x3_rc2::IfcMaterialRelationship::list::ptr Ifc4x3_rc2::IfcMaterial::IsRelatedWith() const { return data_->getInverse(IFC4X3_RC2_IfcMaterialRelationship_type, 3)->as<IfcMaterialRelationship>(); }
@@ -17977,15 +17977,15 @@ Ifc4x3_rc2::IfcMaterialClassificationRelationship::IfcMaterialClassificationRela
 
 // Function implementations for IfcMaterialConstituent
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialConstituent::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialConstituent::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc2::IfcMaterial* Ifc4x3_rc2::IfcMaterialConstituent::Material() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc2::IfcMaterial>(true); }
 void Ifc4x3_rc2::IfcMaterialConstituent::setMaterial(::Ifc4x3_rc2::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcMaterialConstituent::Fraction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialConstituent::Category() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc2::IfcMaterialConstituentSet::list::ptr Ifc4x3_rc2::IfcMaterialConstituent::ToMaterialConstituentSet() const { return data_->getInverse(IFC4X3_RC2_IfcMaterialConstituentSet_type, 2)->as<IfcMaterialConstituentSet>(); }
 
@@ -17996,11 +17996,11 @@ Ifc4x3_rc2::IfcMaterialConstituent::IfcMaterialConstituent(boost::optional< std:
 
 // Function implementations for IfcMaterialConstituentSet
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialConstituentSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialConstituentSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcMaterialConstituent >::ptr > Ifc4x3_rc2::IfcMaterialConstituentSet::MaterialConstituents() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc2::IfcMaterialConstituent >(); }
-void Ifc4x3_rc2::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMaterialConstituentSet::declaration() const { return *IFC4X3_RC2_IfcMaterialConstituentSet_type; }
@@ -18035,15 +18035,15 @@ void Ifc4x3_rc2::IfcMaterialLayer::setMaterial(::Ifc4x3_rc2::IfcMaterial* v) { {
 double Ifc4x3_rc2::IfcMaterialLayer::LayerThickness() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcMaterialLayer::setLayerThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< boost::logic::tribool > Ifc4x3_rc2::IfcMaterialLayer::IsVentilated() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } boost::logic::tribool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialLayer::Name() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialLayer::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialLayer::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x3_rc2::IfcMaterialLayer::Priority() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc2::IfcMaterialLayerSet::list::ptr Ifc4x3_rc2::IfcMaterialLayer::ToMaterialLayerSet() const { return data_->getInverse(IFC4X3_RC2_IfcMaterialLayerSet_type, 0)->as<IfcMaterialLayerSet>(); }
 
@@ -18056,9 +18056,9 @@ Ifc4x3_rc2::IfcMaterialLayer::IfcMaterialLayer(::Ifc4x3_rc2::IfcMaterial* v1_Mat
 aggregate_of< ::Ifc4x3_rc2::IfcMaterialLayer >::ptr Ifc4x3_rc2::IfcMaterialLayerSet::MaterialLayers() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x3_rc2::IfcMaterialLayer >(); }
 void Ifc4x3_rc2::IfcMaterialLayerSet::setMaterialLayers(aggregate_of< ::Ifc4x3_rc2::IfcMaterialLayer >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialLayerSet::LayerSetName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialLayerSet::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMaterialLayerSet::declaration() const { return *IFC4X3_RC2_IfcMaterialLayerSet_type; }
@@ -18076,7 +18076,7 @@ void Ifc4x3_rc2::IfcMaterialLayerSetUsage::setDirectionSense(::Ifc4x3_rc2::IfcDi
 double Ifc4x3_rc2::IfcMaterialLayerSetUsage::OffsetFromReferenceLine() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcMaterialLayerSetUsage::setOffsetFromReferenceLine(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcMaterialLayerSetUsage::ReferenceExtent() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMaterialLayerSetUsage::declaration() const { return *IFC4X3_RC2_IfcMaterialLayerSetUsage_type; }
@@ -18108,17 +18108,17 @@ Ifc4x3_rc2::IfcMaterialList::IfcMaterialList(aggregate_of< ::Ifc4x3_rc2::IfcMate
 
 // Function implementations for IfcMaterialProfile
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialProfile::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialProfile::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc2::IfcMaterial* Ifc4x3_rc2::IfcMaterialProfile::Material() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc2::IfcMaterial>(true); }
 void Ifc4x3_rc2::IfcMaterialProfile::setMaterial(::Ifc4x3_rc2::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcProfileDef* Ifc4x3_rc2::IfcMaterialProfile::Profile() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcProfileDef>(true); }
 void Ifc4x3_rc2::IfcMaterialProfile::setProfile(::Ifc4x3_rc2::IfcProfileDef* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc2::IfcMaterialProfile::Priority() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialProfile::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc2::IfcMaterialProfileSet::list::ptr Ifc4x3_rc2::IfcMaterialProfile::ToMaterialProfileSet() const { return data_->getInverse(IFC4X3_RC2_IfcMaterialProfileSet_type, 2)->as<IfcMaterialProfileSet>(); }
 
@@ -18129,9 +18129,9 @@ Ifc4x3_rc2::IfcMaterialProfile::IfcMaterialProfile(boost::optional< std::string
 
 // Function implementations for IfcMaterialProfileSet
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialProfileSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialProfileSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc2::IfcMaterialProfile >::ptr Ifc4x3_rc2::IfcMaterialProfileSet::MaterialProfiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc2::IfcMaterialProfile >(); }
 void Ifc4x3_rc2::IfcMaterialProfileSet::setMaterialProfiles(aggregate_of< ::Ifc4x3_rc2::IfcMaterialProfile >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcCompositeProfileDef* Ifc4x3_rc2::IfcMaterialProfileSet::CompositeProfile() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcCompositeProfileDef>(true); }
@@ -18147,9 +18147,9 @@ Ifc4x3_rc2::IfcMaterialProfileSet::IfcMaterialProfileSet(boost::optional< std::s
 ::Ifc4x3_rc2::IfcMaterialProfileSet* Ifc4x3_rc2::IfcMaterialProfileSetUsage::ForProfileSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc2::IfcMaterialProfileSet>(true); }
 void Ifc4x3_rc2::IfcMaterialProfileSetUsage::setForProfileSet(::Ifc4x3_rc2::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< int > Ifc4x3_rc2::IfcMaterialProfileSetUsage::CardinalPoint() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } int v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcMaterialProfileSetUsage::ReferenceExtent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMaterialProfileSetUsage::declaration() const { return *IFC4X3_RC2_IfcMaterialProfileSetUsage_type; }
@@ -18161,7 +18161,7 @@ Ifc4x3_rc2::IfcMaterialProfileSetUsage::IfcMaterialProfileSetUsage(::Ifc4x3_rc2:
 ::Ifc4x3_rc2::IfcMaterialProfileSet* Ifc4x3_rc2::IfcMaterialProfileSetUsageTapering::ForProfileEndSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcMaterialProfileSet>(true); }
 void Ifc4x3_rc2::IfcMaterialProfileSetUsageTapering::setForProfileEndSet(::Ifc4x3_rc2::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc2::IfcMaterialProfileSetUsageTapering::CardinalEndPoint() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMaterialProfileSetUsageTapering::declaration() const { return *IFC4X3_RC2_IfcMaterialProfileSetUsageTapering_type; }
@@ -18195,7 +18195,7 @@ void Ifc4x3_rc2::IfcMaterialRelationship::setRelatingMaterial(::Ifc4x3_rc2::IfcM
 aggregate_of< ::Ifc4x3_rc2::IfcMaterial >::ptr Ifc4x3_rc2::IfcMaterialRelationship::RelatedMaterials() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc2::IfcMaterial >(); }
 void Ifc4x3_rc2::IfcMaterialRelationship::setRelatedMaterials(aggregate_of< ::Ifc4x3_rc2::IfcMaterial >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMaterialRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMaterialRelationship::declaration() const { return *IFC4X3_RC2_IfcMaterialRelationship_type; }
@@ -18226,11 +18226,11 @@ Ifc4x3_rc2::IfcMeasureWithUnit::IfcMeasureWithUnit(::Ifc4x3_rc2::IfcValue* v1_Va
 
 // Function implementations for IfcMechanicalFastener
 boost::optional< double > Ifc4x3_rc2::IfcMechanicalFastener::NominalDiameter() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcMechanicalFastener::NominalLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcMechanicalFastenerTypeEnum::Value > Ifc4x3_rc2::IfcMechanicalFastener::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMechanicalFastenerTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMechanicalFastenerTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMechanicalFastener::declaration() const { return *IFC4X3_RC2_IfcMechanicalFastener_type; }
@@ -18242,9 +18242,9 @@ Ifc4x3_rc2::IfcMechanicalFastener::IfcMechanicalFastener(std::string v1_GlobalId
 ::Ifc4x3_rc2::IfcMechanicalFastenerTypeEnum::Value Ifc4x3_rc2::IfcMechanicalFastenerType::PredefinedType() const {  return ::Ifc4x3_rc2::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc2::IfcMechanicalFastenerType::setPredefinedType(::Ifc4x3_rc2::IfcMechanicalFastenerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcMechanicalFastenerTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcMechanicalFastenerType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcMechanicalFastenerType::NominalLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMechanicalFastenerType::declaration() const { return *IFC4X3_RC2_IfcMechanicalFastenerType_type; }
@@ -18254,7 +18254,7 @@ Ifc4x3_rc2::IfcMechanicalFastenerType::IfcMechanicalFastenerType(std::string v1_
 
 // Function implementations for IfcMedicalDevice
 boost::optional< ::Ifc4x3_rc2::IfcMedicalDeviceTypeEnum::Value > Ifc4x3_rc2::IfcMedicalDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcMedicalDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMedicalDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMedicalDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMedicalDevice::declaration() const { return *IFC4X3_RC2_IfcMedicalDevice_type; }
@@ -18274,7 +18274,7 @@ Ifc4x3_rc2::IfcMedicalDeviceType::IfcMedicalDeviceType(std::string v1_GlobalId,
 
 // Function implementations for IfcMember
 boost::optional< ::Ifc4x3_rc2::IfcMemberTypeEnum::Value > Ifc4x3_rc2::IfcMember::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcMemberTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcMember::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMemberTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcMember::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMemberTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMember::declaration() const { return *IFC4X3_RC2_IfcMember_type; }
@@ -18304,7 +18304,7 @@ Ifc4x3_rc2::IfcMemberType::IfcMemberType(std::string v1_GlobalId, ::Ifc4x3_rc2::
 ::Ifc4x3_rc2::IfcBenchmarkEnum::Value Ifc4x3_rc2::IfcMetric::Benchmark() const {  return ::Ifc4x3_rc2::IfcBenchmarkEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc2::IfcMetric::setBenchmark(::Ifc4x3_rc2::IfcBenchmarkEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcBenchmarkEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcMetric::ValueSource() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc2::IfcMetricValueSelect* Ifc4x3_rc2::IfcMetric::DataValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc2::IfcMetricValueSelect>(true); }
 void Ifc4x3_rc2::IfcMetric::setDataValue(::Ifc4x3_rc2::IfcMetricValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x3_rc2::IfcReference* Ifc4x3_rc2::IfcMetric::ReferencePath() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc2::IfcReference>(true); }
@@ -18326,7 +18326,7 @@ Ifc4x3_rc2::IfcMirroredProfileDef::IfcMirroredProfileDef(::Ifc4x3_rc2::IfcProfil
 
 // Function implementations for IfcMobileTelecommunicationsAppliance
 boost::optional< ::Ifc4x3_rc2::IfcMobileTelecommunicationsApplianceTypeEnum::Value > Ifc4x3_rc2::IfcMobileTelecommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcMobileTelecommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcMobileTelecommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMobileTelecommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMobileTelecommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcMobileTelecommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMobileTelecommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMobileTelecommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMobileTelecommunicationsAppliance::declaration() const { return *IFC4X3_RC2_IfcMobileTelecommunicationsAppliance_type; }
@@ -18356,7 +18356,7 @@ Ifc4x3_rc2::IfcMonetaryUnit::IfcMonetaryUnit(std::string v1_Currency) : IfcUtil:
 
 // Function implementations for IfcMooringDevice
 boost::optional< ::Ifc4x3_rc2::IfcMooringDeviceTypeEnum::Value > Ifc4x3_rc2::IfcMooringDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcMooringDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcMooringDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMooringDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMooringDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcMooringDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMooringDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMooringDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMooringDevice::declaration() const { return *IFC4X3_RC2_IfcMooringDevice_type; }
@@ -18376,7 +18376,7 @@ Ifc4x3_rc2::IfcMooringDeviceType::IfcMooringDeviceType(std::string v1_GlobalId,
 
 // Function implementations for IfcMotorConnection
 boost::optional< ::Ifc4x3_rc2::IfcMotorConnectionTypeEnum::Value > Ifc4x3_rc2::IfcMotorConnection::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcMotorConnectionTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMotorConnectionTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcMotorConnectionTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcMotorConnection::declaration() const { return *IFC4X3_RC2_IfcMotorConnection_type; }
@@ -18408,7 +18408,7 @@ Ifc4x3_rc2::IfcNamedUnit::IfcNamedUnit(::Ifc4x3_rc2::IfcDimensionalExponents* v1
 
 // Function implementations for IfcNavigationElement
 boost::optional< ::Ifc4x3_rc2::IfcNavigationElementTypeEnum::Value > Ifc4x3_rc2::IfcNavigationElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcNavigationElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcNavigationElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcNavigationElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcNavigationElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcNavigationElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcNavigationElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcNavigationElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcNavigationElement::declaration() const { return *IFC4X3_RC2_IfcNavigationElement_type; }
@@ -18428,7 +18428,7 @@ Ifc4x3_rc2::IfcNavigationElementType::IfcNavigationElementType(std::string v1_Gl
 
 // Function implementations for IfcObject
 boost::optional< std::string > Ifc4x3_rc2::IfcObject::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc2::IfcRelDefinesByObject::list::ptr Ifc4x3_rc2::IfcObject::IsDeclaredBy() const { return data_->getInverse(IFC4X3_RC2_IfcRelDefinesByObject_type, 4)->as<IfcRelDefinesByObject>(); }
 ::Ifc4x3_rc2::IfcRelDefinesByObject::list::ptr Ifc4x3_rc2::IfcObject::Declares() const { return data_->getInverse(IFC4X3_RC2_IfcRelDefinesByObject_type, 5)->as<IfcRelDefinesByObject>(); }
@@ -18468,13 +18468,13 @@ Ifc4x3_rc2::IfcObjectPlacement::IfcObjectPlacement(::Ifc4x3_rc2::IfcObjectPlacem
 
 // Function implementations for IfcObjective
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcConstraint >::ptr > Ifc4x3_rc2::IfcObjective::BenchmarkValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc2::IfcConstraint >(); }
-void Ifc4x3_rc2::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcLogicalOperatorEnum::Value > Ifc4x3_rc2::IfcObjective::LogicalAggregator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcLogicalOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x3_rc2::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcLogicalOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x3_rc2::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcLogicalOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc2::IfcObjectiveEnum::Value Ifc4x3_rc2::IfcObjective::ObjectiveQualifier() const {  return ::Ifc4x3_rc2::IfcObjectiveEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc2::IfcObjective::setObjectiveQualifier(::Ifc4x3_rc2::IfcObjectiveEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcObjectiveEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcObjective::UserDefinedQualifier() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcObjective::declaration() const { return *IFC4X3_RC2_IfcObjective_type; }
@@ -18484,7 +18484,7 @@ Ifc4x3_rc2::IfcObjective::IfcObjective(std::string v1_Name, boost::optional< std
 
 // Function implementations for IfcOccupant
 boost::optional< ::Ifc4x3_rc2::IfcOccupantTypeEnum::Value > Ifc4x3_rc2::IfcOccupant::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcOccupantTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc2::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcOccupantTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcOccupantTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcOccupant::declaration() const { return *IFC4X3_RC2_IfcOccupant_type; }
@@ -18532,7 +18532,7 @@ Ifc4x3_rc2::IfcOffsetCurve3D::IfcOffsetCurve3D(::Ifc4x3_rc2::IfcCurve* v1_BasisC
 aggregate_of< ::Ifc4x3_rc2::IfcPointByDistanceExpression >::ptr Ifc4x3_rc2::IfcOffsetCurveByDistances::OffsetValues() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc2::IfcPointByDistanceExpression >(); }
 void Ifc4x3_rc2::IfcOffsetCurveByDistances::setOffsetValues(aggregate_of< ::Ifc4x3_rc2::IfcPointByDistanceExpression >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcOffsetCurveByDistances::Tag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcOffsetCurveByDistances::declaration() const { return *IFC4X3_RC2_IfcOffsetCurveByDistances_type; }
@@ -18548,7 +18548,7 @@ void Ifc4x3_rc2::IfcOpenCrossProfileDef::setWidths(std::vector< double > /*[1:?]
 std::vector< double > /*[1:?]*/ Ifc4x3_rc2::IfcOpenCrossProfileDef::Slopes() const {  std::vector< double > /*[1:?]*/ v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc2::IfcOpenCrossProfileDef::setSlopes(std::vector< double > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[2:?]*/ > Ifc4x3_rc2::IfcOpenCrossProfileDef::Tags() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[2:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcOpenCrossProfileDef::setTags(boost::optional< std::vector< std::string > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcOpenCrossProfileDef::setTags(boost::optional< std::vector< std::string > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcOpenCrossProfileDef::declaration() const { return *IFC4X3_RC2_IfcOpenCrossProfileDef_type; }
@@ -18566,7 +18566,7 @@ Ifc4x3_rc2::IfcOpenShell::IfcOpenShell(aggregate_of< ::Ifc4x3_rc2::IfcFace >::pt
 
 // Function implementations for IfcOpeningElement
 boost::optional< ::Ifc4x3_rc2::IfcOpeningElementTypeEnum::Value > Ifc4x3_rc2::IfcOpeningElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcOpeningElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcOpeningElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcOpeningElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc2::IfcRelFillsElement::list::ptr Ifc4x3_rc2::IfcOpeningElement::HasFillings() const { return data_->getInverse(IFC4X3_RC2_IfcRelFillsElement_type, 4)->as<IfcRelFillsElement>(); }
 
@@ -18585,15 +18585,15 @@ Ifc4x3_rc2::IfcOpeningStandardCase::IfcOpeningStandardCase(std::string v1_Global
 
 // Function implementations for IfcOrganization
 boost::optional< std::string > Ifc4x3_rc2::IfcOrganization::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 std::string Ifc4x3_rc2::IfcOrganization::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcOrganization::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcOrganization::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcActorRole >::ptr > Ifc4x3_rc2::IfcOrganization::Roles() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc2::IfcActorRole >(); }
-void Ifc4x3_rc2::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(3,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAddress >::ptr > Ifc4x3_rc2::IfcOrganization::Addresses() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x3_rc2::IfcAddress >(); }
-void Ifc4x3_rc2::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc2::IfcOrganizationRelationship::list::ptr Ifc4x3_rc2::IfcOrganization::IsRelatedBy() const { return data_->getInverse(IFC4X3_RC2_IfcOrganizationRelationship_type, 3)->as<IfcOrganizationRelationship>(); }
 ::Ifc4x3_rc2::IfcOrganizationRelationship::list::ptr Ifc4x3_rc2::IfcOrganization::Relates() const { return data_->getInverse(IFC4X3_RC2_IfcOrganizationRelationship_type, 2)->as<IfcOrganizationRelationship>(); }
@@ -18638,7 +18638,7 @@ Ifc4x3_rc2::IfcOuterBoundaryCurve::IfcOuterBoundaryCurve(aggregate_of< ::Ifc4x3_
 
 // Function implementations for IfcOutlet
 boost::optional< ::Ifc4x3_rc2::IfcOutletTypeEnum::Value > Ifc4x3_rc2::IfcOutlet::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcOutletTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcOutletTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcOutletTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcOutlet::declaration() const { return *IFC4X3_RC2_IfcOutlet_type; }
@@ -18662,11 +18662,11 @@ void Ifc4x3_rc2::IfcOwnerHistory::setOwningUser(::Ifc4x3_rc2::IfcPersonAndOrgani
 ::Ifc4x3_rc2::IfcApplication* Ifc4x3_rc2::IfcOwnerHistory::OwningApplication() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc2::IfcApplication>(true); }
 void Ifc4x3_rc2::IfcOwnerHistory::setOwningApplication(::Ifc4x3_rc2::IfcApplication* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcStateEnum::Value > Ifc4x3_rc2::IfcOwnerHistory::State() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcStateEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc2::IfcOwnerHistory::setState(boost::optional< ::Ifc4x3_rc2::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcStateEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcOwnerHistory::setState(boost::optional< ::Ifc4x3_rc2::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcStateEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcChangeActionEnum::Value > Ifc4x3_rc2::IfcOwnerHistory::ChangeAction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcChangeActionEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x3_rc2::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x3_rc2::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcChangeActionEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x3_rc2::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcChangeActionEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc2::IfcOwnerHistory::LastModifiedDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc2::IfcPersonAndOrganization* Ifc4x3_rc2::IfcOwnerHistory::LastModifyingUser() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc2::IfcPersonAndOrganization>(true); }
 void Ifc4x3_rc2::IfcOwnerHistory::setLastModifyingUser(::Ifc4x3_rc2::IfcPersonAndOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x3_rc2::IfcApplication* Ifc4x3_rc2::IfcOwnerHistory::LastModifyingApplication() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcApplication>(true); }
@@ -18702,7 +18702,7 @@ Ifc4x3_rc2::IfcPath::IfcPath(aggregate_of< ::Ifc4x3_rc2::IfcOrientedEdge >::ptr
 
 // Function implementations for IfcPavement
 boost::optional< bool > Ifc4x3_rc2::IfcPavement::Flexible() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } bool v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcPavement::setFlexible(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcPavement::setFlexible(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPavement::declaration() const { return *IFC4X3_RC2_IfcPavement_type; }
@@ -18736,7 +18736,7 @@ Ifc4x3_rc2::IfcPcurve::IfcPcurve(::Ifc4x3_rc2::IfcSurface* v1_BasisSurface, ::If
 std::string Ifc4x3_rc2::IfcPerformanceHistory::LifeCyclePhase() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcPerformanceHistory::setLifeCyclePhase(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcPerformanceHistoryTypeEnum::Value > Ifc4x3_rc2::IfcPerformanceHistory::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcPerformanceHistoryTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc2::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPerformanceHistoryTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPerformanceHistoryTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPerformanceHistory::declaration() const { return *IFC4X3_RC2_IfcPerformanceHistory_type; }
@@ -18750,9 +18750,9 @@ void Ifc4x3_rc2::IfcPermeableCoveringProperties::setOperationType(::Ifc4x3_rc2::
 ::Ifc4x3_rc2::IfcWindowPanelPositionEnum::Value Ifc4x3_rc2::IfcPermeableCoveringProperties::PanelPosition() const {  return ::Ifc4x3_rc2::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc2::IfcPermeableCoveringProperties::setPanelPosition(::Ifc4x3_rc2::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcPermeableCoveringProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcPermeableCoveringProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc2::IfcShapeAspect* Ifc4x3_rc2::IfcPermeableCoveringProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc2::IfcShapeAspect>(true); }
 void Ifc4x3_rc2::IfcPermeableCoveringProperties::setShapeAspectStyle(::Ifc4x3_rc2::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -18764,11 +18764,11 @@ Ifc4x3_rc2::IfcPermeableCoveringProperties::IfcPermeableCoveringProperties(std::
 
 // Function implementations for IfcPermit
 boost::optional< ::Ifc4x3_rc2::IfcPermitTypeEnum::Value > Ifc4x3_rc2::IfcPermit::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcPermitTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc2::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPermitTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPermitTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPermit::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPermit::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPermit::declaration() const { return *IFC4X3_RC2_IfcPermit_type; }
@@ -18778,21 +18778,21 @@ Ifc4x3_rc2::IfcPermit::IfcPermit(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwner
 
 // Function implementations for IfcPerson
 boost::optional< std::string > Ifc4x3_rc2::IfcPerson::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPerson::FamilyName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPerson::GivenName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcPerson::MiddleNames() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcPerson::PrefixTitles() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcPerson::SuffixTitles() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcActorRole >::ptr > Ifc4x3_rc2::IfcPerson::Roles() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc2::IfcActorRole >(); }
-void Ifc4x3_rc2::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAddress >::ptr > Ifc4x3_rc2::IfcPerson::Addresses() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc2::IfcAddress >(); }
-void Ifc4x3_rc2::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc2::IfcPersonAndOrganization::list::ptr Ifc4x3_rc2::IfcPerson::EngagedIn() const { return data_->getInverse(IFC4X3_RC2_IfcPersonAndOrganization_type, 0)->as<IfcPersonAndOrganization>(); }
 
@@ -18807,7 +18807,7 @@ void Ifc4x3_rc2::IfcPersonAndOrganization::setThePerson(::Ifc4x3_rc2::IfcPerson*
 ::Ifc4x3_rc2::IfcOrganization* Ifc4x3_rc2::IfcPersonAndOrganization::TheOrganization() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc2::IfcOrganization>(true); }
 void Ifc4x3_rc2::IfcPersonAndOrganization::setTheOrganization(::Ifc4x3_rc2::IfcOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcActorRole >::ptr > Ifc4x3_rc2::IfcPersonAndOrganization::Roles() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc2::IfcActorRole >(); }
-void Ifc4x3_rc2::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPersonAndOrganization::declaration() const { return *IFC4X3_RC2_IfcPersonAndOrganization_type; }
@@ -18821,9 +18821,9 @@ void Ifc4x3_rc2::IfcPhysicalComplexQuantity::setHasQuantities(aggregate_of< ::If
 std::string Ifc4x3_rc2::IfcPhysicalComplexQuantity::Discrimination() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcPhysicalComplexQuantity::setDiscrimination(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPhysicalComplexQuantity::Quality() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPhysicalComplexQuantity::Usage() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPhysicalComplexQuantity::declaration() const { return *IFC4X3_RC2_IfcPhysicalComplexQuantity_type; }
@@ -18835,7 +18835,7 @@ Ifc4x3_rc2::IfcPhysicalComplexQuantity::IfcPhysicalComplexQuantity(std::string v
 std::string Ifc4x3_rc2::IfcPhysicalQuantity::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc2::IfcPhysicalQuantity::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPhysicalQuantity::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc2::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc2::IfcPhysicalQuantity::HasExternalReferences() const { return data_->getInverse(IFC4X3_RC2_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc2::IfcPhysicalComplexQuantity::list::ptr Ifc4x3_rc2::IfcPhysicalQuantity::PartOfComplex() const { return data_->getInverse(IFC4X3_RC2_IfcPhysicalComplexQuantity_type, 2)->as<IfcPhysicalComplexQuantity>(); }
@@ -18857,9 +18857,9 @@ Ifc4x3_rc2::IfcPhysicalSimpleQuantity::IfcPhysicalSimpleQuantity(std::string v1_
 
 // Function implementations for IfcPile
 boost::optional< ::Ifc4x3_rc2::IfcPileTypeEnum::Value > Ifc4x3_rc2::IfcPile::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcPileTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcPile::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPileTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcPile::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPileTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcPileConstructionEnum::Value > Ifc4x3_rc2::IfcPile::ConstructionType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcPileConstructionEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc2::IfcPile::setConstructionType(boost::optional< ::Ifc4x3_rc2::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPileConstructionEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcPile::setConstructionType(boost::optional< ::Ifc4x3_rc2::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPileConstructionEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPile::declaration() const { return *IFC4X3_RC2_IfcPile_type; }
@@ -18879,7 +18879,7 @@ Ifc4x3_rc2::IfcPileType::IfcPileType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcPipeFitting
 boost::optional< ::Ifc4x3_rc2::IfcPipeFittingTypeEnum::Value > Ifc4x3_rc2::IfcPipeFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcPipeFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPipeFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPipeFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPipeFitting::declaration() const { return *IFC4X3_RC2_IfcPipeFitting_type; }
@@ -18899,7 +18899,7 @@ Ifc4x3_rc2::IfcPipeFittingType::IfcPipeFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcPipeSegment
 boost::optional< ::Ifc4x3_rc2::IfcPipeSegmentTypeEnum::Value > Ifc4x3_rc2::IfcPipeSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcPipeSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPipeSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPipeSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPipeSegment::declaration() const { return *IFC4X3_RC2_IfcPipeSegment_type; }
@@ -18983,7 +18983,7 @@ Ifc4x3_rc2::IfcPlant::IfcPlant(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHi
 
 // Function implementations for IfcPlate
 boost::optional< ::Ifc4x3_rc2::IfcPlateTypeEnum::Value > Ifc4x3_rc2::IfcPlate::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcPlateTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPlateTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPlateTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPlate::declaration() const { return *IFC4X3_RC2_IfcPlate_type; }
@@ -19021,11 +19021,11 @@ Ifc4x3_rc2::IfcPoint::IfcPoint() : IfcGeometricRepresentationItem((IfcEntityInst
 ::Ifc4x3_rc2::IfcCurveMeasureSelect* Ifc4x3_rc2::IfcPointByDistanceExpression::DistanceAlong() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc2::IfcCurveMeasureSelect>(true); }
 void Ifc4x3_rc2::IfcPointByDistanceExpression::setDistanceAlong(::Ifc4x3_rc2::IfcCurveMeasureSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcPointByDistanceExpression::OffsetLateral() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcPointByDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcPointByDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcPointByDistanceExpression::OffsetVertical() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcPointByDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcPointByDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcPointByDistanceExpression::OffsetLongitudinal() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcPointByDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcPointByDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc2::IfcCurve* Ifc4x3_rc2::IfcPointByDistanceExpression::BasisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc2::IfcCurve>(true); }
 void Ifc4x3_rc2::IfcPointByDistanceExpression::setBasisCurve(::Ifc4x3_rc2::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -19085,11 +19085,11 @@ Ifc4x3_rc2::IfcPolygonalBoundedHalfSpace::IfcPolygonalBoundedHalfSpace(::Ifc4x3_
 
 // Function implementations for IfcPolygonalFaceSet
 boost::optional< bool > Ifc4x3_rc2::IfcPolygonalFaceSet::Closed() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc2::IfcIndexedPolygonalFace >::ptr Ifc4x3_rc2::IfcPolygonalFaceSet::Faces() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc2::IfcIndexedPolygonalFace >(); }
 void Ifc4x3_rc2::IfcPolygonalFaceSet::setFaces(aggregate_of< ::Ifc4x3_rc2::IfcIndexedPolygonalFace >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc2::IfcPolygonalFaceSet::PnIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPolygonalFaceSet::declaration() const { return *IFC4X3_RC2_IfcPolygonalFaceSet_type; }
@@ -19130,19 +19130,19 @@ Ifc4x3_rc2::IfcPositioningElement::IfcPositioningElement(std::string v1_GlobalId
 
 // Function implementations for IfcPostalAddress
 boost::optional< std::string > Ifc4x3_rc2::IfcPostalAddress::InternalLocation() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcPostalAddress::AddressLines() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPostalAddress::PostalBox() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPostalAddress::Town() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPostalAddress::Region() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPostalAddress::PostalCode() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPostalAddress::Country() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPostalAddress::declaration() const { return *IFC4X3_RC2_IfcPostalAddress_type; }
@@ -19212,11 +19212,11 @@ Ifc4x3_rc2::IfcPresentationItem::IfcPresentationItem() : IfcUtil::IfcBaseEntity(
 std::string Ifc4x3_rc2::IfcPresentationLayerAssignment::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc2::IfcPresentationLayerAssignment::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPresentationLayerAssignment::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of_instance::ptr Ifc4x3_rc2::IfcPresentationLayerAssignment::AssignedItems() const {  aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc2::IfcPresentationLayerAssignment::setAssignedItems(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPresentationLayerAssignment::Identifier() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPresentationLayerAssignment::declaration() const { return *IFC4X3_RC2_IfcPresentationLayerAssignment_type; }
@@ -19242,7 +19242,7 @@ Ifc4x3_rc2::IfcPresentationLayerWithStyle::IfcPresentationLayerWithStyle(std::st
 
 // Function implementations for IfcPresentationStyle
 boost::optional< std::string > Ifc4x3_rc2::IfcPresentationStyle::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPresentationStyle::declaration() const { return *IFC4X3_RC2_IfcPresentationStyle_type; }
@@ -19262,7 +19262,7 @@ Ifc4x3_rc2::IfcPresentationStyleAssignment::IfcPresentationStyleAssignment(aggre
 
 // Function implementations for IfcProcedure
 boost::optional< ::Ifc4x3_rc2::IfcProcedureTypeEnum::Value > Ifc4x3_rc2::IfcProcedure::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcProcedureTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc2::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProcedureTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProcedureTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcProcedure::declaration() const { return *IFC4X3_RC2_IfcProcedure_type; }
@@ -19282,9 +19282,9 @@ Ifc4x3_rc2::IfcProcedureType::IfcProcedureType(std::string v1_GlobalId, ::Ifc4x3
 
 // Function implementations for IfcProcess
 boost::optional< std::string > Ifc4x3_rc2::IfcProcess::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcProcess::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc2::IfcRelSequence::list::ptr Ifc4x3_rc2::IfcProcess::IsPredecessorTo() const { return data_->getInverse(IFC4X3_RC2_IfcRelSequence_type, 4)->as<IfcRelSequence>(); }
 ::Ifc4x3_rc2::IfcRelSequence::list::ptr Ifc4x3_rc2::IfcProcess::IsSuccessorFrom() const { return data_->getInverse(IFC4X3_RC2_IfcRelSequence_type, 5)->as<IfcRelSequence>(); }
@@ -19322,9 +19322,9 @@ Ifc4x3_rc2::IfcProductDefinitionShape::IfcProductDefinitionShape(boost::optional
 
 // Function implementations for IfcProductRepresentation
 boost::optional< std::string > Ifc4x3_rc2::IfcProductRepresentation::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcProductRepresentation::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc2::IfcRepresentation >::ptr Ifc4x3_rc2::IfcProductRepresentation::Representations() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc2::IfcRepresentation >(); }
 void Ifc4x3_rc2::IfcProductRepresentation::setRepresentations(aggregate_of< ::Ifc4x3_rc2::IfcRepresentation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -19338,7 +19338,7 @@ Ifc4x3_rc2::IfcProductRepresentation::IfcProductRepresentation(boost::optional<
 ::Ifc4x3_rc2::IfcProfileTypeEnum::Value Ifc4x3_rc2::IfcProfileDef::ProfileType() const {  return ::Ifc4x3_rc2::IfcProfileTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc2::IfcProfileDef::setProfileType(::Ifc4x3_rc2::IfcProfileTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcProfileTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcProfileDef::ProfileName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc2::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc2::IfcProfileDef::HasExternalReference() const { return data_->getInverse(IFC4X3_RC2_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc2::IfcProfileProperties::list::ptr Ifc4x3_rc2::IfcProfileDef::HasProperties() const { return data_->getInverse(IFC4X3_RC2_IfcProfileProperties_type, 3)->as<IfcProfileProperties>(); }
@@ -19376,11 +19376,11 @@ Ifc4x3_rc2::IfcProjectLibrary::IfcProjectLibrary(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcProjectOrder
 boost::optional< ::Ifc4x3_rc2::IfcProjectOrderTypeEnum::Value > Ifc4x3_rc2::IfcProjectOrder::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcProjectOrderTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc2::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProjectOrderTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProjectOrderTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcProjectOrder::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcProjectOrder::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcProjectOrder::declaration() const { return *IFC4X3_RC2_IfcProjectOrder_type; }
@@ -19390,9 +19390,9 @@ Ifc4x3_rc2::IfcProjectOrder::IfcProjectOrder(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcProjectedCRS
 boost::optional< std::string > Ifc4x3_rc2::IfcProjectedCRS::MapProjection() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcProjectedCRS::MapZone() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc2::IfcNamedUnit* Ifc4x3_rc2::IfcProjectedCRS::MapUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcNamedUnit>(true); }
 void Ifc4x3_rc2::IfcProjectedCRS::setMapUnit(::Ifc4x3_rc2::IfcNamedUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -19404,7 +19404,7 @@ Ifc4x3_rc2::IfcProjectedCRS::IfcProjectedCRS(std::string v1_Name, boost::optiona
 
 // Function implementations for IfcProjectionElement
 boost::optional< ::Ifc4x3_rc2::IfcProjectionElementTypeEnum::Value > Ifc4x3_rc2::IfcProjectionElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcProjectionElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProjectionElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProjectionElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcProjectionElement::declaration() const { return *IFC4X3_RC2_IfcProjectionElement_type; }
@@ -19416,7 +19416,7 @@ Ifc4x3_rc2::IfcProjectionElement::IfcProjectionElement(std::string v1_GlobalId,
 std::string Ifc4x3_rc2::IfcProperty::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc2::IfcProperty::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcProperty::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc2::IfcPropertySet::list::ptr Ifc4x3_rc2::IfcProperty::PartOfPset() const { return data_->getInverse(IFC4X3_RC2_IfcPropertySet_type, 4)->as<IfcPropertySet>(); }
 ::Ifc4x3_rc2::IfcPropertyDependencyRelationship::list::ptr Ifc4x3_rc2::IfcProperty::PropertyForDependance() const { return data_->getInverse(IFC4X3_RC2_IfcPropertyDependencyRelationship_type, 2)->as<IfcPropertyDependencyRelationship>(); }
@@ -19471,7 +19471,7 @@ void Ifc4x3_rc2::IfcPropertyDependencyRelationship::setDependingProperty(::Ifc4x
 ::Ifc4x3_rc2::IfcProperty* Ifc4x3_rc2::IfcPropertyDependencyRelationship::DependantProperty() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcProperty>(true); }
 void Ifc4x3_rc2::IfcPropertyDependencyRelationship::setDependantProperty(::Ifc4x3_rc2::IfcProperty* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPropertyDependencyRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPropertyDependencyRelationship::declaration() const { return *IFC4X3_RC2_IfcPropertyDependencyRelationship_type; }
@@ -19481,7 +19481,7 @@ Ifc4x3_rc2::IfcPropertyDependencyRelationship::IfcPropertyDependencyRelationship
 
 // Function implementations for IfcPropertyEnumeratedValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc2::IfcPropertyEnumeratedValue::EnumerationValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcPropertyEnumeration* Ifc4x3_rc2::IfcPropertyEnumeratedValue::EnumerationReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcPropertyEnumeration>(true); }
 void Ifc4x3_rc2::IfcPropertyEnumeratedValue::setEnumerationReference(::Ifc4x3_rc2::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19507,7 +19507,7 @@ Ifc4x3_rc2::IfcPropertyEnumeration::IfcPropertyEnumeration(std::string v1_Name,
 
 // Function implementations for IfcPropertyListValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc2::IfcPropertyListValue::ListValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcUnit* Ifc4x3_rc2::IfcPropertyListValue::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcUnit>(true); }
 void Ifc4x3_rc2::IfcPropertyListValue::setUnit(::Ifc4x3_rc2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19519,7 +19519,7 @@ Ifc4x3_rc2::IfcPropertyListValue::IfcPropertyListValue(std::string v1_Name, boos
 
 // Function implementations for IfcPropertyReferenceValue
 boost::optional< std::string > Ifc4x3_rc2::IfcPropertyReferenceValue::UsageName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcObjectReferenceSelect* Ifc4x3_rc2::IfcPropertyReferenceValue::PropertyReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcObjectReferenceSelect>(true); }
 void Ifc4x3_rc2::IfcPropertyReferenceValue::setPropertyReference(::Ifc4x3_rc2::IfcObjectReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19552,9 +19552,9 @@ Ifc4x3_rc2::IfcPropertySetDefinition::IfcPropertySetDefinition(std::string v1_Gl
 
 // Function implementations for IfcPropertySetTemplate
 boost::optional< ::Ifc4x3_rc2::IfcPropertySetTemplateTypeEnum::Value > Ifc4x3_rc2::IfcPropertySetTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcPropertySetTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x3_rc2::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc2::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPropertySetTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc2::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPropertySetTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPropertySetTemplate::ApplicableEntity() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 aggregate_of< ::Ifc4x3_rc2::IfcPropertyTemplate >::ptr Ifc4x3_rc2::IfcPropertySetTemplate::HasPropertyTemplates() const {  aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc2::IfcPropertyTemplate >(); }
 void Ifc4x3_rc2::IfcPropertySetTemplate::setHasPropertyTemplates(aggregate_of< ::Ifc4x3_rc2::IfcPropertyTemplate >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(6,attr);} }
 
@@ -19579,17 +19579,17 @@ Ifc4x3_rc2::IfcPropertySingleValue::IfcPropertySingleValue(std::string v1_Name,
 
 // Function implementations for IfcPropertyTableValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc2::IfcPropertyTableValue::DefiningValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc2::IfcPropertyTableValue::DefinedValues() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcPropertyTableValue::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc2::IfcUnit* Ifc4x3_rc2::IfcPropertyTableValue::DefiningUnit() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc2::IfcUnit>(true); }
 void Ifc4x3_rc2::IfcPropertyTableValue::setDefiningUnit(::Ifc4x3_rc2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x3_rc2::IfcUnit* Ifc4x3_rc2::IfcPropertyTableValue::DefinedUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcUnit>(true); }
 void Ifc4x3_rc2::IfcPropertyTableValue::setDefinedUnit(::Ifc4x3_rc2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcCurveInterpolationEnum::Value > Ifc4x3_rc2::IfcPropertyTableValue::CurveInterpolation() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcCurveInterpolationEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc2::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x3_rc2::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCurveInterpolationEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x3_rc2::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcCurveInterpolationEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPropertyTableValue::declaration() const { return *IFC4X3_RC2_IfcPropertyTableValue_type; }
@@ -19617,7 +19617,7 @@ Ifc4x3_rc2::IfcPropertyTemplateDefinition::IfcPropertyTemplateDefinition(std::st
 
 // Function implementations for IfcProtectiveDevice
 boost::optional< ::Ifc4x3_rc2::IfcProtectiveDeviceTypeEnum::Value > Ifc4x3_rc2::IfcProtectiveDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcProtectiveDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProtectiveDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProtectiveDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcProtectiveDevice::declaration() const { return *IFC4X3_RC2_IfcProtectiveDevice_type; }
@@ -19627,7 +19627,7 @@ Ifc4x3_rc2::IfcProtectiveDevice::IfcProtectiveDevice(std::string v1_GlobalId, ::
 
 // Function implementations for IfcProtectiveDeviceTrippingUnit
 boost::optional< ::Ifc4x3_rc2::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > Ifc4x3_rc2::IfcProtectiveDeviceTrippingUnit::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcProtectiveDeviceTrippingUnitTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcProtectiveDeviceTrippingUnit::declaration() const { return *IFC4X3_RC2_IfcProtectiveDeviceTrippingUnit_type; }
@@ -19659,7 +19659,7 @@ Ifc4x3_rc2::IfcProtectiveDeviceType::IfcProtectiveDeviceType(std::string v1_Glob
 ::Ifc4x3_rc2::IfcObjectTypeEnum::Value Ifc4x3_rc2::IfcProxy::ProxyType() const {  return ::Ifc4x3_rc2::IfcObjectTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc2::IfcProxy::setProxyType(::Ifc4x3_rc2::IfcObjectTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcObjectTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcProxy::Tag() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcProxy::declaration() const { return *IFC4X3_RC2_IfcProxy_type; }
@@ -19669,7 +19669,7 @@ Ifc4x3_rc2::IfcProxy::IfcProxy(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHi
 
 // Function implementations for IfcPump
 boost::optional< ::Ifc4x3_rc2::IfcPumpTypeEnum::Value > Ifc4x3_rc2::IfcPump::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcPumpTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcPump::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPumpTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcPump::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcPumpTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcPump::declaration() const { return *IFC4X3_RC2_IfcPump_type; }
@@ -19691,7 +19691,7 @@ Ifc4x3_rc2::IfcPumpType::IfcPumpType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 double Ifc4x3_rc2::IfcQuantityArea::AreaValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcQuantityArea::setAreaValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcQuantityArea::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcQuantityArea::declaration() const { return *IFC4X3_RC2_IfcQuantityArea_type; }
@@ -19703,7 +19703,7 @@ Ifc4x3_rc2::IfcQuantityArea::IfcQuantityArea(std::string v1_Name, boost::optiona
 double Ifc4x3_rc2::IfcQuantityCount::CountValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcQuantityCount::setCountValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcQuantityCount::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcQuantityCount::declaration() const { return *IFC4X3_RC2_IfcQuantityCount_type; }
@@ -19715,7 +19715,7 @@ Ifc4x3_rc2::IfcQuantityCount::IfcQuantityCount(std::string v1_Name, boost::optio
 double Ifc4x3_rc2::IfcQuantityLength::LengthValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcQuantityLength::setLengthValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcQuantityLength::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcQuantityLength::declaration() const { return *IFC4X3_RC2_IfcQuantityLength_type; }
@@ -19735,7 +19735,7 @@ Ifc4x3_rc2::IfcQuantitySet::IfcQuantitySet(std::string v1_GlobalId, ::Ifc4x3_rc2
 double Ifc4x3_rc2::IfcQuantityTime::TimeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcQuantityTime::setTimeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcQuantityTime::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcQuantityTime::declaration() const { return *IFC4X3_RC2_IfcQuantityTime_type; }
@@ -19747,7 +19747,7 @@ Ifc4x3_rc2::IfcQuantityTime::IfcQuantityTime(std::string v1_Name, boost::optiona
 double Ifc4x3_rc2::IfcQuantityVolume::VolumeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcQuantityVolume::setVolumeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcQuantityVolume::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcQuantityVolume::declaration() const { return *IFC4X3_RC2_IfcQuantityVolume_type; }
@@ -19759,7 +19759,7 @@ Ifc4x3_rc2::IfcQuantityVolume::IfcQuantityVolume(std::string v1_Name, boost::opt
 double Ifc4x3_rc2::IfcQuantityWeight::WeightValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcQuantityWeight::setWeightValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcQuantityWeight::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcQuantityWeight::declaration() const { return *IFC4X3_RC2_IfcQuantityWeight_type; }
@@ -19769,7 +19769,7 @@ Ifc4x3_rc2::IfcQuantityWeight::IfcQuantityWeight(std::string v1_Name, boost::opt
 
 // Function implementations for IfcRail
 boost::optional< ::Ifc4x3_rc2::IfcRailTypeEnum::Value > Ifc4x3_rc2::IfcRail::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcRailTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcRail::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcRailTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcRailTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcRail::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcRailTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcRailTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRail::declaration() const { return *IFC4X3_RC2_IfcRail_type; }
@@ -19789,7 +19789,7 @@ Ifc4x3_rc2::IfcRailType::IfcRailType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcRailing
 boost::optional< ::Ifc4x3_rc2::IfcRailingTypeEnum::Value > Ifc4x3_rc2::IfcRailing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcRailingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcRailingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcRailingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRailing::declaration() const { return *IFC4X3_RC2_IfcRailing_type; }
@@ -19817,7 +19817,7 @@ Ifc4x3_rc2::IfcRailway::IfcRailway(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwn
 
 // Function implementations for IfcRamp
 boost::optional< ::Ifc4x3_rc2::IfcRampTypeEnum::Value > Ifc4x3_rc2::IfcRamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcRampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcRampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcRampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRamp::declaration() const { return *IFC4X3_RC2_IfcRamp_type; }
@@ -19827,7 +19827,7 @@ Ifc4x3_rc2::IfcRamp::IfcRamp(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHist
 
 // Function implementations for IfcRampFlight
 boost::optional< ::Ifc4x3_rc2::IfcRampFlightTypeEnum::Value > Ifc4x3_rc2::IfcRampFlight::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcRampFlightTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcRampFlightTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcRampFlightTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRampFlight::declaration() const { return *IFC4X3_RC2_IfcRampFlight_type; }
@@ -19879,9 +19879,9 @@ Ifc4x3_rc2::IfcRationalBSplineSurfaceWithKnots::IfcRationalBSplineSurfaceWithKno
 double Ifc4x3_rc2::IfcRectangleHollowProfileDef::WallThickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc2::IfcRectangleHollowProfileDef::setWallThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcRectangleHollowProfileDef::InnerFilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcRectangleHollowProfileDef::OuterFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRectangleHollowProfileDef::declaration() const { return *IFC4X3_RC2_IfcRectangleHollowProfileDef_type; }
@@ -19941,19 +19941,19 @@ Ifc4x3_rc2::IfcRectangularTrimmedSurface::IfcRectangularTrimmedSurface(::Ifc4x3_
 ::Ifc4x3_rc2::IfcRecurrenceTypeEnum::Value Ifc4x3_rc2::IfcRecurrencePattern::RecurrenceType() const {  return ::Ifc4x3_rc2::IfcRecurrenceTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc2::IfcRecurrencePattern::setRecurrenceType(::Ifc4x3_rc2::IfcRecurrenceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcRecurrenceTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc2::IfcRecurrencePattern::DayComponent() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc2::IfcRecurrencePattern::WeekdayComponent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc2::IfcRecurrencePattern::MonthComponent() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc2::IfcRecurrencePattern::Position() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< int > Ifc4x3_rc2::IfcRecurrencePattern::Interval() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } int v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x3_rc2::IfcRecurrencePattern::Occurrences() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcTimePeriod >::ptr > Ifc4x3_rc2::IfcRecurrencePattern::TimePeriods() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc2::IfcTimePeriod >(); }
-void Ifc4x3_rc2::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRecurrencePattern::declaration() const { return *IFC4X3_RC2_IfcRecurrencePattern_type; }
@@ -19963,13 +19963,13 @@ Ifc4x3_rc2::IfcRecurrencePattern::IfcRecurrencePattern(::Ifc4x3_rc2::IfcRecurren
 
 // Function implementations for IfcReference
 boost::optional< std::string > Ifc4x3_rc2::IfcReference::TypeIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcReference::AttributeIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcReference::InstanceName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc2::IfcReference::ListPositions() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc2::IfcReference* Ifc4x3_rc2::IfcReference::InnerReference() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc2::IfcReference>(true); }
 void Ifc4x3_rc2::IfcReference::setInnerReference(::Ifc4x3_rc2::IfcReference* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -19981,9 +19981,9 @@ Ifc4x3_rc2::IfcReference::IfcReference(boost::optional< std::string > v1_TypeIde
 
 // Function implementations for IfcReferent
 boost::optional< ::Ifc4x3_rc2::IfcReferentTypeEnum::Value > Ifc4x3_rc2::IfcReferent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcReferentTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc2::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReferentTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReferentTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReferent::RestartDistance() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcReferent::declaration() const { return *IFC4X3_RC2_IfcReferent_type; }
@@ -20005,7 +20005,7 @@ Ifc4x3_rc2::IfcRegularTimeSeries::IfcRegularTimeSeries(std::string v1_Name, boos
 
 // Function implementations for IfcReinforcedSoil
 boost::optional< ::Ifc4x3_rc2::IfcReinforcedSoilTypeEnum::Value > Ifc4x3_rc2::IfcReinforcedSoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcReinforcedSoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcReinforcedSoil::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcReinforcedSoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcedSoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcReinforcedSoil::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcReinforcedSoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcedSoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcReinforcedSoil::declaration() const { return *IFC4X3_RC2_IfcReinforcedSoil_type; }
@@ -20019,13 +20019,13 @@ void Ifc4x3_rc2::IfcReinforcementBarProperties::setTotalCrossSectionArea(double
 std::string Ifc4x3_rc2::IfcReinforcementBarProperties::SteelGrade() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcReinforcementBarProperties::setSteelGrade(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc2::IfcReinforcementBarProperties::BarSurface() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc2::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcementBarProperties::EffectiveDepth() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcementBarProperties::NominalBarDiameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcementBarProperties::BarCount() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcReinforcementBarProperties::declaration() const { return *IFC4X3_RC2_IfcReinforcementBarProperties_type; }
@@ -20035,7 +20035,7 @@ Ifc4x3_rc2::IfcReinforcementBarProperties::IfcReinforcementBarProperties(double
 
 // Function implementations for IfcReinforcementDefinitionProperties
 boost::optional< std::string > Ifc4x3_rc2::IfcReinforcementDefinitionProperties::DefinitionType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x3_rc2::IfcSectionReinforcementProperties >::ptr Ifc4x3_rc2::IfcReinforcementDefinitionProperties::ReinforcementSectionDefinitions() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc2::IfcSectionReinforcementProperties >(); }
 void Ifc4x3_rc2::IfcReinforcementDefinitionProperties::setReinforcementSectionDefinitions(aggregate_of< ::Ifc4x3_rc2::IfcSectionReinforcementProperties >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -20047,15 +20047,15 @@ Ifc4x3_rc2::IfcReinforcementDefinitionProperties::IfcReinforcementDefinitionProp
 
 // Function implementations for IfcReinforcingBar
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingBar::NominalDiameter() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingBar::CrossSectionArea() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingBar::BarLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarTypeEnum::Value > Ifc4x3_rc2::IfcReinforcingBar::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc2::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcingBarTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcingBarTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc2::IfcReinforcingBar::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc2::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcReinforcingBar::declaration() const { return *IFC4X3_RC2_IfcReinforcingBar_type; }
@@ -20067,17 +20067,17 @@ Ifc4x3_rc2::IfcReinforcingBar::IfcReinforcingBar(std::string v1_GlobalId, ::Ifc4
 ::Ifc4x3_rc2::IfcReinforcingBarTypeEnum::Value Ifc4x3_rc2::IfcReinforcingBarType::PredefinedType() const {  return ::Ifc4x3_rc2::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc2::IfcReinforcingBarType::setPredefinedType(::Ifc4x3_rc2::IfcReinforcingBarTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcReinforcingBarTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingBarType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingBarType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingBarType::BarLength() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc2::IfcReinforcingBarType::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc2::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcReinforcingBarType::BendingShapeCode() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc2::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc2::IfcReinforcingBarType::BendingParameters() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc2::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc2::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcReinforcingBarType::declaration() const { return *IFC4X3_RC2_IfcReinforcingBarType_type; }
@@ -20087,7 +20087,7 @@ Ifc4x3_rc2::IfcReinforcingBarType::IfcReinforcingBarType(std::string v1_GlobalId
 
 // Function implementations for IfcReinforcingElement
 boost::optional< std::string > Ifc4x3_rc2::IfcReinforcingElement::SteelGrade() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcReinforcingElement::declaration() const { return *IFC4X3_RC2_IfcReinforcingElement_type; }
@@ -20105,23 +20105,23 @@ Ifc4x3_rc2::IfcReinforcingElementType::IfcReinforcingElementType(std::string v1_
 
 // Function implementations for IfcReinforcingMesh
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMesh::MeshLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMesh::MeshWidth() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMesh::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMesh::TransverseBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMesh::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc2::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMesh::TransverseBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc2::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMesh::LongitudinalBarSpacing() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc2::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMesh::TransverseBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc2::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcReinforcingMeshTypeEnum::Value > Ifc4x3_rc2::IfcReinforcingMesh::PredefinedType() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(17)); }
-void Ifc4x3_rc2::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcingMeshTypeEnum::ToString(*v)));data_->setArgument(17,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcReinforcingMeshTypeEnum::ToString(*v)));}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcReinforcingMesh::declaration() const { return *IFC4X3_RC2_IfcReinforcingMesh_type; }
@@ -20133,25 +20133,25 @@ Ifc4x3_rc2::IfcReinforcingMesh::IfcReinforcingMesh(std::string v1_GlobalId, ::If
 ::Ifc4x3_rc2::IfcReinforcingMeshTypeEnum::Value Ifc4x3_rc2::IfcReinforcingMeshType::PredefinedType() const {  return ::Ifc4x3_rc2::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc2::IfcReinforcingMeshType::setPredefinedType(::Ifc4x3_rc2::IfcReinforcingMeshTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcReinforcingMeshTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMeshType::MeshLength() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMeshType::MeshWidth() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMeshType::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMeshType::TransverseBarNominalDiameter() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc2::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMeshType::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc2::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMeshType::TransverseBarCrossSectionArea() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc2::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMeshType::LongitudinalBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc2::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcReinforcingMeshType::TransverseBarSpacing() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc2::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcReinforcingMeshType::BendingShapeCode() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x3_rc2::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc2::IfcReinforcingMeshType::BendingParameters() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(19); return v; }
-void Ifc4x3_rc2::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x3_rc2::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcReinforcingMeshType::declaration() const { return *IFC4X3_RC2_IfcReinforcingMeshType_type; }
@@ -20175,7 +20175,7 @@ Ifc4x3_rc2::IfcRelAggregates::IfcRelAggregates(std::string v1_GlobalId, ::Ifc4x3
 aggregate_of< ::Ifc4x3_rc2::IfcObjectDefinition >::ptr Ifc4x3_rc2::IfcRelAssigns::RelatedObjects() const {  aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x3_rc2::IfcObjectDefinition >(); }
 void Ifc4x3_rc2::IfcRelAssigns::setRelatedObjects(aggregate_of< ::Ifc4x3_rc2::IfcObjectDefinition >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcObjectTypeEnum::Value > Ifc4x3_rc2::IfcRelAssigns::RelatedObjectsType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcObjectTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc2::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x3_rc2::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcObjectTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x3_rc2::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcObjectTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRelAssigns::declaration() const { return *IFC4X3_RC2_IfcRelAssigns_type; }
@@ -20289,7 +20289,7 @@ Ifc4x3_rc2::IfcRelAssociatesClassification::IfcRelAssociatesClassification(std::
 
 // Function implementations for IfcRelAssociatesConstraint
 boost::optional< std::string > Ifc4x3_rc2::IfcRelAssociatesConstraint::Intent() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc2::IfcConstraint* Ifc4x3_rc2::IfcRelAssociatesConstraint::RelatingConstraint() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcConstraint>(true); }
 void Ifc4x3_rc2::IfcRelAssociatesConstraint::setRelatingConstraint(::Ifc4x3_rc2::IfcConstraint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -20425,7 +20425,7 @@ void Ifc4x3_rc2::IfcRelConnectsStructuralMember::setAppliedCondition(::Ifc4x3_rc
 ::Ifc4x3_rc2::IfcStructuralConnectionCondition* Ifc4x3_rc2::IfcRelConnectsStructuralMember::AdditionalConditions() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc2::IfcStructuralConnectionCondition>(true); }
 void Ifc4x3_rc2::IfcRelConnectsStructuralMember::setAdditionalConditions(::Ifc4x3_rc2::IfcStructuralConnectionCondition* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcRelConnectsStructuralMember::SupportedLength() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc2::IfcAxis2Placement3D* Ifc4x3_rc2::IfcRelConnectsStructuralMember::ConditionCoordinateSystem() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc2::IfcAxis2Placement3D>(true); }
 void Ifc4x3_rc2::IfcRelConnectsStructuralMember::setConditionCoordinateSystem(::Ifc4x3_rc2::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -20449,7 +20449,7 @@ Ifc4x3_rc2::IfcRelConnectsWithEccentricity::IfcRelConnectsWithEccentricity(std::
 aggregate_of< ::Ifc4x3_rc2::IfcElement >::ptr Ifc4x3_rc2::IfcRelConnectsWithRealizingElements::RealizingElements() const {  aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc2::IfcElement >(); }
 void Ifc4x3_rc2::IfcRelConnectsWithRealizingElements::setRealizingElements(aggregate_of< ::Ifc4x3_rc2::IfcElement >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcRelConnectsWithRealizingElements::ConnectionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRelConnectsWithRealizingElements::declaration() const { return *IFC4X3_RC2_IfcRelConnectsWithRealizingElements_type; }
@@ -20601,7 +20601,7 @@ void Ifc4x3_rc2::IfcRelInterferesElements::setRelatedElement(::Ifc4x3_rc2::IfcIn
 ::Ifc4x3_rc2::IfcConnectionGeometry* Ifc4x3_rc2::IfcRelInterferesElements::InterferenceGeometry() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcConnectionGeometry>(true); }
 void Ifc4x3_rc2::IfcRelInterferesElements::setInterferenceGeometry(::Ifc4x3_rc2::IfcConnectionGeometry* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcRelInterferesElements::InterferenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::logic::tribool Ifc4x3_rc2::IfcRelInterferesElements::ImpliedOrder() const {  boost::logic::tribool v = *data_->getArgument(8); return v; }
 void Ifc4x3_rc2::IfcRelInterferesElements::setImpliedOrder(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -20667,9 +20667,9 @@ void Ifc4x3_rc2::IfcRelSequence::setRelatedProcess(::Ifc4x3_rc2::IfcProcess* v)
 ::Ifc4x3_rc2::IfcLagTime* Ifc4x3_rc2::IfcRelSequence::TimeLag() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcLagTime>(true); }
 void Ifc4x3_rc2::IfcRelSequence::setTimeLag(::Ifc4x3_rc2::IfcLagTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcSequenceEnum::Value > Ifc4x3_rc2::IfcRelSequence::SequenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSequenceEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc2::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x3_rc2::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSequenceEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x3_rc2::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSequenceEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcRelSequence::UserDefinedSequenceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRelSequence::declaration() const { return *IFC4X3_RC2_IfcRelSequence_type; }
@@ -20763,9 +20763,9 @@ Ifc4x3_rc2::IfcReparametrisedCompositeCurveSegment::IfcReparametrisedCompositeCu
 ::Ifc4x3_rc2::IfcRepresentationContext* Ifc4x3_rc2::IfcRepresentation::ContextOfItems() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc2::IfcRepresentationContext>(true); }
 void Ifc4x3_rc2::IfcRepresentation::setContextOfItems(::Ifc4x3_rc2::IfcRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcRepresentation::RepresentationIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcRepresentation::RepresentationType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc4x3_rc2::IfcRepresentationItem >::ptr Ifc4x3_rc2::IfcRepresentation::Items() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc2::IfcRepresentationItem >(); }
 void Ifc4x3_rc2::IfcRepresentation::setItems(aggregate_of< ::Ifc4x3_rc2::IfcRepresentationItem >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 
@@ -20780,9 +20780,9 @@ Ifc4x3_rc2::IfcRepresentation::IfcRepresentation(::Ifc4x3_rc2::IfcRepresentation
 
 // Function implementations for IfcRepresentationContext
 boost::optional< std::string > Ifc4x3_rc2::IfcRepresentationContext::ContextIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcRepresentationContext::ContextType() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc2::IfcRepresentation::list::ptr Ifc4x3_rc2::IfcRepresentationContext::RepresentationsInContext() const { return data_->getInverse(IFC4X3_RC2_IfcRepresentation_type, 0)->as<IfcRepresentation>(); }
 
@@ -20817,9 +20817,9 @@ Ifc4x3_rc2::IfcRepresentationMap::IfcRepresentationMap(::Ifc4x3_rc2::IfcAxis2Pla
 
 // Function implementations for IfcResource
 boost::optional< std::string > Ifc4x3_rc2::IfcResource::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResource::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc2::IfcRelAssignsToResource::list::ptr Ifc4x3_rc2::IfcResource::ResourceOf() const { return data_->getInverse(IFC4X3_RC2_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -20854,9 +20854,9 @@ Ifc4x3_rc2::IfcResourceConstraintRelationship::IfcResourceConstraintRelationship
 
 // Function implementations for IfcResourceLevelRelationship
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceLevelRelationship::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceLevelRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcResourceLevelRelationship::declaration() const { return *IFC4X3_RC2_IfcResourceLevelRelationship_type; }
@@ -20866,35 +20866,35 @@ Ifc4x3_rc2::IfcResourceLevelRelationship::IfcResourceLevelRelationship(boost::op
 
 // Function implementations for IfcResourceTime
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceTime::ScheduleWork() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcResourceTime::ScheduleUsage() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceTime::ScheduleContour() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceTime::LevelingDelay() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< bool > Ifc4x3_rc2::IfcResourceTime::IsOverAllocated() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceTime::StatusTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceTime::ActualWork() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcResourceTime::ActualUsage() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceTime::ActualStart() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceTime::ActualFinish() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcResourceTime::RemainingWork() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcResourceTime::RemainingUsage() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcResourceTime::Completion() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc2::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc2::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcResourceTime::declaration() const { return *IFC4X3_RC2_IfcResourceTime_type; }
@@ -20958,7 +20958,7 @@ Ifc4x3_rc2::IfcRoad::IfcRoad(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHist
 
 // Function implementations for IfcRoof
 boost::optional< ::Ifc4x3_rc2::IfcRoofTypeEnum::Value > Ifc4x3_rc2::IfcRoof::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcRoofTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcRoofTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcRoofTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRoof::declaration() const { return *IFC4X3_RC2_IfcRoof_type; }
@@ -20982,9 +20982,9 @@ void Ifc4x3_rc2::IfcRoot::setGlobalId(std::string v) { {IfcWrite::IfcWriteArgume
 ::Ifc4x3_rc2::IfcOwnerHistory* Ifc4x3_rc2::IfcRoot::OwnerHistory() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc2::IfcOwnerHistory>(true); }
 void Ifc4x3_rc2::IfcRoot::setOwnerHistory(::Ifc4x3_rc2::IfcOwnerHistory* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcRoot::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcRoot::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcRoot::declaration() const { return *IFC4X3_RC2_IfcRoot_type; }
@@ -21004,7 +21004,7 @@ Ifc4x3_rc2::IfcRoundedRectangleProfileDef::IfcRoundedRectangleProfileDef(::Ifc4x
 
 // Function implementations for IfcSIUnit
 boost::optional< ::Ifc4x3_rc2::IfcSIPrefix::Value > Ifc4x3_rc2::IfcSIUnit::Prefix() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSIPrefix::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc2::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x3_rc2::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSIPrefix::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x3_rc2::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSIPrefix::ToString(*v)));}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcSIUnitName::Value Ifc4x3_rc2::IfcSIUnit::Name() const {  return ::Ifc4x3_rc2::IfcSIUnitName::FromString(*data_->getArgument(3)); }
 void Ifc4x3_rc2::IfcSIUnit::setName(::Ifc4x3_rc2::IfcSIUnitName::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcSIUnitName::ToString(v)));data_->setArgument(3,attr);} }
 
@@ -21016,7 +21016,7 @@ Ifc4x3_rc2::IfcSIUnit::IfcSIUnit(::Ifc4x3_rc2::IfcUnitEnum::Value v2_UnitType, b
 
 // Function implementations for IfcSanitaryTerminal
 boost::optional< ::Ifc4x3_rc2::IfcSanitaryTerminalTypeEnum::Value > Ifc4x3_rc2::IfcSanitaryTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSanitaryTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSanitaryTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSanitaryTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSanitaryTerminal::declaration() const { return *IFC4X3_RC2_IfcSanitaryTerminal_type; }
@@ -21036,11 +21036,11 @@ Ifc4x3_rc2::IfcSanitaryTerminalType::IfcSanitaryTerminalType(std::string v1_Glob
 
 // Function implementations for IfcSchedulingTime
 boost::optional< std::string > Ifc4x3_rc2::IfcSchedulingTime::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcDataOriginEnum::Value > Ifc4x3_rc2::IfcSchedulingTime::DataOrigin() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcDataOriginEnum::FromString(*data_->getArgument(1)); }
-void Ifc4x3_rc2::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x3_rc2::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDataOriginEnum::ToString(*v)));data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x3_rc2::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcDataOriginEnum::ToString(*v)));}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcSchedulingTime::UserDefinedDataOrigin() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSchedulingTime::declaration() const { return *IFC4X3_RC2_IfcSchedulingTime_type; }
@@ -21076,7 +21076,7 @@ void Ifc4x3_rc2::IfcSectionReinforcementProperties::setLongitudinalStartPosition
 double Ifc4x3_rc2::IfcSectionReinforcementProperties::LongitudinalEndPosition() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcSectionReinforcementProperties::setLongitudinalEndPosition(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSectionReinforcementProperties::TransversePosition() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcReinforcingBarRoleEnum::Value Ifc4x3_rc2::IfcSectionReinforcementProperties::ReinforcementRole() const {  return ::Ifc4x3_rc2::IfcReinforcingBarRoleEnum::FromString(*data_->getArgument(3)); }
 void Ifc4x3_rc2::IfcSectionReinforcementProperties::setReinforcementRole(::Ifc4x3_rc2::IfcReinforcingBarRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcReinforcingBarRoleEnum::ToString(v)));data_->setArgument(3,attr);} }
 ::Ifc4x3_rc2::IfcSectionProperties* Ifc4x3_rc2::IfcSectionReinforcementProperties::SectionDefinition() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc2::IfcSectionProperties>(true); }
@@ -21170,7 +21170,7 @@ Ifc4x3_rc2::IfcSegmentedReferenceCurve::IfcSegmentedReferenceCurve(::Ifc4x3_rc2:
 
 // Function implementations for IfcSensor
 boost::optional< ::Ifc4x3_rc2::IfcSensorTypeEnum::Value > Ifc4x3_rc2::IfcSensor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSensorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSensorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSensorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSensor::declaration() const { return *IFC4X3_RC2_IfcSensor_type; }
@@ -21204,7 +21204,7 @@ Ifc4x3_rc2::IfcSeriesParameterCurve::IfcSeriesParameterCurve(::Ifc4x3_rc2::IfcPl
 
 // Function implementations for IfcShadingDevice
 boost::optional< ::Ifc4x3_rc2::IfcShadingDeviceTypeEnum::Value > Ifc4x3_rc2::IfcShadingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcShadingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcShadingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcShadingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcShadingDevice::declaration() const { return *IFC4X3_RC2_IfcShadingDevice_type; }
@@ -21226,9 +21226,9 @@ Ifc4x3_rc2::IfcShadingDeviceType::IfcShadingDeviceType(std::string v1_GlobalId,
 aggregate_of< ::Ifc4x3_rc2::IfcShapeModel >::ptr Ifc4x3_rc2::IfcShapeAspect::ShapeRepresentations() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x3_rc2::IfcShapeModel >(); }
 void Ifc4x3_rc2::IfcShapeAspect::setShapeRepresentations(aggregate_of< ::Ifc4x3_rc2::IfcShapeModel >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcShapeAspect::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcShapeAspect::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::logic::tribool Ifc4x3_rc2::IfcShapeAspect::ProductDefinitional() const {  boost::logic::tribool v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcShapeAspect::setProductDefinitional(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc2::IfcProductRepresentationSelect* Ifc4x3_rc2::IfcShapeAspect::PartOfProductDefinitionShape() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc2::IfcProductRepresentationSelect>(true); }
@@ -21270,7 +21270,7 @@ Ifc4x3_rc2::IfcShellBasedSurfaceModel::IfcShellBasedSurfaceModel(aggregate_of_in
 
 // Function implementations for IfcSign
 boost::optional< ::Ifc4x3_rc2::IfcSignTypeEnum::Value > Ifc4x3_rc2::IfcSign::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSignTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSign::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSignTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSignTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSign::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSignTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSignTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSign::declaration() const { return *IFC4X3_RC2_IfcSign_type; }
@@ -21290,7 +21290,7 @@ Ifc4x3_rc2::IfcSignType::IfcSignType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcSignal
 boost::optional< ::Ifc4x3_rc2::IfcSignalTypeEnum::Value > Ifc4x3_rc2::IfcSignal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSignalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSignal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSignalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSignalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSignal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSignalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSignalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSignal::declaration() const { return *IFC4X3_RC2_IfcSignal_type; }
@@ -21318,11 +21318,11 @@ Ifc4x3_rc2::IfcSimpleProperty::IfcSimpleProperty(std::string v1_Name, boost::opt
 
 // Function implementations for IfcSimplePropertyTemplate
 boost::optional< ::Ifc4x3_rc2::IfcSimplePropertyTemplateTypeEnum::Value > Ifc4x3_rc2::IfcSimplePropertyTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSimplePropertyTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x3_rc2::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc2::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc2::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcSimplePropertyTemplate::PrimaryMeasureType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcSimplePropertyTemplate::SecondaryMeasureType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc2::IfcPropertyEnumeration* Ifc4x3_rc2::IfcSimplePropertyTemplate::Enumerators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc2::IfcPropertyEnumeration>(true); }
 void Ifc4x3_rc2::IfcSimplePropertyTemplate::setEnumerators(::Ifc4x3_rc2::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x3_rc2::IfcUnit* Ifc4x3_rc2::IfcSimplePropertyTemplate::PrimaryUnit() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc2::IfcUnit>(true); }
@@ -21330,9 +21330,9 @@ void Ifc4x3_rc2::IfcSimplePropertyTemplate::setPrimaryUnit(::Ifc4x3_rc2::IfcUnit
 ::Ifc4x3_rc2::IfcUnit* Ifc4x3_rc2::IfcSimplePropertyTemplate::SecondaryUnit() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc2::IfcUnit>(true); }
 void Ifc4x3_rc2::IfcSimplePropertyTemplate::setSecondaryUnit(::Ifc4x3_rc2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcSimplePropertyTemplate::Expression() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcStateEnum::Value > Ifc4x3_rc2::IfcSimplePropertyTemplate::AccessState() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcStateEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc2::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x3_rc2::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcStateEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x3_rc2::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcStateEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSimplePropertyTemplate::declaration() const { return *IFC4X3_RC2_IfcSimplePropertyTemplate_type; }
@@ -21342,13 +21342,13 @@ Ifc4x3_rc2::IfcSimplePropertyTemplate::IfcSimplePropertyTemplate(std::string v1_
 
 // Function implementations for IfcSite
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x3_rc2::IfcSite::RefLatitude() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x3_rc2::IfcSite::RefLongitude() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSite::RefElevation() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcSite::LandTitleNumber() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x3_rc2::IfcPostalAddress* Ifc4x3_rc2::IfcSite::SiteAddress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x3_rc2::IfcPostalAddress>(true); }
 void Ifc4x3_rc2::IfcSite::setSiteAddress(::Ifc4x3_rc2::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -21360,7 +21360,7 @@ Ifc4x3_rc2::IfcSite::IfcSite(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHist
 
 // Function implementations for IfcSlab
 boost::optional< ::Ifc4x3_rc2::IfcSlabTypeEnum::Value > Ifc4x3_rc2::IfcSlab::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSlabTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSlabTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSlabTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSlab::declaration() const { return *IFC4X3_RC2_IfcSlab_type; }
@@ -21396,11 +21396,11 @@ Ifc4x3_rc2::IfcSlabType::IfcSlabType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcSlippageConnectionCondition
 boost::optional< double > Ifc4x3_rc2::IfcSlippageConnectionCondition::SlippageX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSlippageConnectionCondition::SlippageY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSlippageConnectionCondition::SlippageZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSlippageConnectionCondition::declaration() const { return *IFC4X3_RC2_IfcSlippageConnectionCondition_type; }
@@ -21410,7 +21410,7 @@ Ifc4x3_rc2::IfcSlippageConnectionCondition::IfcSlippageConnectionCondition(boost
 
 // Function implementations for IfcSolarDevice
 boost::optional< ::Ifc4x3_rc2::IfcSolarDeviceTypeEnum::Value > Ifc4x3_rc2::IfcSolarDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSolarDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSolarDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSolarDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSolarDevice::declaration() const { return *IFC4X3_RC2_IfcSolarDevice_type; }
@@ -21446,9 +21446,9 @@ Ifc4x3_rc2::IfcSolidStratum::IfcSolidStratum(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcSpace
 boost::optional< ::Ifc4x3_rc2::IfcSpaceTypeEnum::Value > Ifc4x3_rc2::IfcSpace::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc2::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSpaceTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSpaceTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSpace::ElevationWithFlooring() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 ::Ifc4x3_rc2::IfcRelCoversSpaces::list::ptr Ifc4x3_rc2::IfcSpace::HasCoverings() const { return data_->getInverse(IFC4X3_RC2_IfcRelCoversSpaces_type, 4)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x3_rc2::IfcRelSpaceBoundary::list::ptr Ifc4x3_rc2::IfcSpace::BoundedBy() const { return data_->getInverse(IFC4X3_RC2_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
@@ -21460,7 +21460,7 @@ Ifc4x3_rc2::IfcSpace::IfcSpace(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHi
 
 // Function implementations for IfcSpaceHeater
 boost::optional< ::Ifc4x3_rc2::IfcSpaceHeaterTypeEnum::Value > Ifc4x3_rc2::IfcSpaceHeater::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSpaceHeaterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSpaceHeaterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSpaceHeaterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSpaceHeater::declaration() const { return *IFC4X3_RC2_IfcSpaceHeater_type; }
@@ -21482,7 +21482,7 @@ Ifc4x3_rc2::IfcSpaceHeaterType::IfcSpaceHeaterType(std::string v1_GlobalId, ::If
 ::Ifc4x3_rc2::IfcSpaceTypeEnum::Value Ifc4x3_rc2::IfcSpaceType::PredefinedType() const {  return ::Ifc4x3_rc2::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc2::IfcSpaceType::setPredefinedType(::Ifc4x3_rc2::IfcSpaceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcSpaceTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcSpaceType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSpaceType::declaration() const { return *IFC4X3_RC2_IfcSpaceType_type; }
@@ -21492,7 +21492,7 @@ Ifc4x3_rc2::IfcSpaceType::IfcSpaceType(std::string v1_GlobalId, ::Ifc4x3_rc2::If
 
 // Function implementations for IfcSpatialElement
 boost::optional< std::string > Ifc4x3_rc2::IfcSpatialElement::LongName() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc2::IfcRelContainedInSpatialStructure::list::ptr Ifc4x3_rc2::IfcSpatialElement::ContainsElements() const { return data_->getInverse(IFC4X3_RC2_IfcRelContainedInSpatialStructure_type, 5)->as<IfcRelContainedInSpatialStructure>(); }
 ::Ifc4x3_rc2::IfcRelServicesBuildings::list::ptr Ifc4x3_rc2::IfcSpatialElement::ServicedBySystems() const { return data_->getInverse(IFC4X3_RC2_IfcRelServicesBuildings_type, 5)->as<IfcRelServicesBuildings>(); }
@@ -21505,7 +21505,7 @@ Ifc4x3_rc2::IfcSpatialElement::IfcSpatialElement(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcSpatialElementType
 boost::optional< std::string > Ifc4x3_rc2::IfcSpatialElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSpatialElementType::declaration() const { return *IFC4X3_RC2_IfcSpatialElementType_type; }
@@ -21515,7 +21515,7 @@ Ifc4x3_rc2::IfcSpatialElementType::IfcSpatialElementType(std::string v1_GlobalId
 
 // Function implementations for IfcSpatialStructureElement
 boost::optional< ::Ifc4x3_rc2::IfcElementCompositionEnum::Value > Ifc4x3_rc2::IfcSpatialStructureElement::CompositionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcElementCompositionEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x3_rc2::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElementCompositionEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x3_rc2::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcElementCompositionEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSpatialStructureElement::declaration() const { return *IFC4X3_RC2_IfcSpatialStructureElement_type; }
@@ -21533,7 +21533,7 @@ Ifc4x3_rc2::IfcSpatialStructureElementType::IfcSpatialStructureElementType(std::
 
 // Function implementations for IfcSpatialZone
 boost::optional< ::Ifc4x3_rc2::IfcSpatialZoneTypeEnum::Value > Ifc4x3_rc2::IfcSpatialZone::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSpatialZoneTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSpatialZoneTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSpatialZone::declaration() const { return *IFC4X3_RC2_IfcSpatialZone_type; }
@@ -21545,7 +21545,7 @@ Ifc4x3_rc2::IfcSpatialZone::IfcSpatialZone(std::string v1_GlobalId, ::Ifc4x3_rc2
 ::Ifc4x3_rc2::IfcSpatialZoneTypeEnum::Value Ifc4x3_rc2::IfcSpatialZoneType::PredefinedType() const {  return ::Ifc4x3_rc2::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc2::IfcSpatialZoneType::setPredefinedType(::Ifc4x3_rc2::IfcSpatialZoneTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcSpatialZoneTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcSpatialZoneType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSpatialZoneType::declaration() const { return *IFC4X3_RC2_IfcSpatialZoneType_type; }
@@ -21575,7 +21575,7 @@ Ifc4x3_rc2::IfcSphericalSurface::IfcSphericalSurface(::Ifc4x3_rc2::IfcAxis2Place
 
 // Function implementations for IfcStackTerminal
 boost::optional< ::Ifc4x3_rc2::IfcStackTerminalTypeEnum::Value > Ifc4x3_rc2::IfcStackTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcStackTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcStackTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcStackTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStackTerminal::declaration() const { return *IFC4X3_RC2_IfcStackTerminal_type; }
@@ -21595,7 +21595,7 @@ Ifc4x3_rc2::IfcStackTerminalType::IfcStackTerminalType(std::string v1_GlobalId,
 
 // Function implementations for IfcStair
 boost::optional< ::Ifc4x3_rc2::IfcStairTypeEnum::Value > Ifc4x3_rc2::IfcStair::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcStairTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcStair::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcStairTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcStair::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcStairTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStair::declaration() const { return *IFC4X3_RC2_IfcStair_type; }
@@ -21605,15 +21605,15 @@ Ifc4x3_rc2::IfcStair::IfcStair(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHi
 
 // Function implementations for IfcStairFlight
 boost::optional< int > Ifc4x3_rc2::IfcStairFlight::NumberOfRisers() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } int v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< int > Ifc4x3_rc2::IfcStairFlight::NumberOfTreads() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } int v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStairFlight::RiserHeight() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStairFlight::TreadLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcStairFlightTypeEnum::Value > Ifc4x3_rc2::IfcStairFlight::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcStairFlightTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc2::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcStairFlightTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcStairFlightTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStairFlight::declaration() const { return *IFC4X3_RC2_IfcStairFlight_type; }
@@ -21643,7 +21643,7 @@ Ifc4x3_rc2::IfcStairType::IfcStairType(std::string v1_GlobalId, ::Ifc4x3_rc2::If
 
 // Function implementations for IfcStructuralAction
 boost::optional< bool > Ifc4x3_rc2::IfcStructuralAction::DestabilizingLoad() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralAction::declaration() const { return *IFC4X3_RC2_IfcStructuralAction_type; }
@@ -21670,9 +21670,9 @@ void Ifc4x3_rc2::IfcStructuralAnalysisModel::setPredefinedType(::Ifc4x3_rc2::Ifc
 ::Ifc4x3_rc2::IfcAxis2Placement3D* Ifc4x3_rc2::IfcStructuralAnalysisModel::OrientationOf2DPlane() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcAxis2Placement3D>(true); }
 void Ifc4x3_rc2::IfcStructuralAnalysisModel::setOrientationOf2DPlane(::Ifc4x3_rc2::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcStructuralLoadGroup >::ptr > Ifc4x3_rc2::IfcStructuralAnalysisModel::LoadedBy() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc2::IfcStructuralLoadGroup >(); }
-void Ifc4x3_rc2::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcStructuralResultGroup >::ptr > Ifc4x3_rc2::IfcStructuralAnalysisModel::HasResults() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc2::IfcStructuralResultGroup >(); }
-void Ifc4x3_rc2::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc2::IfcObjectPlacement* Ifc4x3_rc2::IfcStructuralAnalysisModel::SharedPlacement() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc2::IfcObjectPlacement>(true); }
 void Ifc4x3_rc2::IfcStructuralAnalysisModel::setSharedPlacement(::Ifc4x3_rc2::IfcObjectPlacement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -21695,7 +21695,7 @@ Ifc4x3_rc2::IfcStructuralConnection::IfcStructuralConnection(std::string v1_Glob
 
 // Function implementations for IfcStructuralConnectionCondition
 boost::optional< std::string > Ifc4x3_rc2::IfcStructuralConnectionCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralConnectionCondition::declaration() const { return *IFC4X3_RC2_IfcStructuralConnectionCondition_type; }
@@ -21705,7 +21705,7 @@ Ifc4x3_rc2::IfcStructuralConnectionCondition::IfcStructuralConnectionCondition(b
 
 // Function implementations for IfcStructuralCurveAction
 boost::optional< ::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::Value > Ifc4x3_rc2::IfcStructuralCurveAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc2::IfcStructuralCurveActivityTypeEnum::Value Ifc4x3_rc2::IfcStructuralCurveAction::PredefinedType() const {  return ::Ifc4x3_rc2::IfcStructuralCurveActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x3_rc2::IfcStructuralCurveAction::setPredefinedType(::Ifc4x3_rc2::IfcStructuralCurveActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcStructuralCurveActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -21774,7 +21774,7 @@ Ifc4x3_rc2::IfcStructuralLinearAction::IfcStructuralLinearAction(std::string v1_
 
 // Function implementations for IfcStructuralLoad
 boost::optional< std::string > Ifc4x3_rc2::IfcStructuralLoad::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralLoad::declaration() const { return *IFC4X3_RC2_IfcStructuralLoad_type; }
@@ -21784,7 +21784,7 @@ Ifc4x3_rc2::IfcStructuralLoad::IfcStructuralLoad(boost::optional< std::string >
 
 // Function implementations for IfcStructuralLoadCase
 boost::optional< std::vector< double > /*[3:3]*/ > Ifc4x3_rc2::IfcStructuralLoadCase::SelfWeightCoefficients() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< double > /*[3:3]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralLoadCase::declaration() const { return *IFC4X3_RC2_IfcStructuralLoadCase_type; }
@@ -21796,7 +21796,7 @@ Ifc4x3_rc2::IfcStructuralLoadCase::IfcStructuralLoadCase(std::string v1_GlobalId
 aggregate_of< ::Ifc4x3_rc2::IfcStructuralLoadOrResult >::ptr Ifc4x3_rc2::IfcStructuralLoadConfiguration::Values() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc2::IfcStructuralLoadOrResult >(); }
 void Ifc4x3_rc2::IfcStructuralLoadConfiguration::setValues(aggregate_of< ::Ifc4x3_rc2::IfcStructuralLoadOrResult >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::vector< std::vector< double > > > Ifc4x3_rc2::IfcStructuralLoadConfiguration::Locations() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralLoadConfiguration::declaration() const { return *IFC4X3_RC2_IfcStructuralLoadConfiguration_type; }
@@ -21812,9 +21812,9 @@ void Ifc4x3_rc2::IfcStructuralLoadGroup::setActionType(::Ifc4x3_rc2::IfcActionTy
 ::Ifc4x3_rc2::IfcActionSourceTypeEnum::Value Ifc4x3_rc2::IfcStructuralLoadGroup::ActionSource() const {  return ::Ifc4x3_rc2::IfcActionSourceTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc2::IfcStructuralLoadGroup::setActionSource(::Ifc4x3_rc2::IfcActionSourceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcActionSourceTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadGroup::Coefficient() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcStructuralLoadGroup::Purpose() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 ::Ifc4x3_rc2::IfcStructuralResultGroup::list::ptr Ifc4x3_rc2::IfcStructuralLoadGroup::SourceOfResultGroup() const { return data_->getInverse(IFC4X3_RC2_IfcStructuralResultGroup_type, 6)->as<IfcStructuralResultGroup>(); }
 ::Ifc4x3_rc2::IfcStructuralAnalysisModel::list::ptr Ifc4x3_rc2::IfcStructuralLoadGroup::LoadGroupFor() const { return data_->getInverse(IFC4X3_RC2_IfcStructuralAnalysisModel_type, 7)->as<IfcStructuralAnalysisModel>(); }
@@ -21826,17 +21826,17 @@ Ifc4x3_rc2::IfcStructuralLoadGroup::IfcStructuralLoadGroup(std::string v1_Global
 
 // Function implementations for IfcStructuralLoadLinearForce
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadLinearForce::LinearForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadLinearForce::LinearForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadLinearForce::LinearForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadLinearForce::LinearMomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadLinearForce::LinearMomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadLinearForce::LinearMomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralLoadLinearForce::declaration() const { return *IFC4X3_RC2_IfcStructuralLoadLinearForce_type; }
@@ -21854,11 +21854,11 @@ Ifc4x3_rc2::IfcStructuralLoadOrResult::IfcStructuralLoadOrResult(boost::optional
 
 // Function implementations for IfcStructuralLoadPlanarForce
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadPlanarForce::PlanarForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadPlanarForce::PlanarForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadPlanarForce::PlanarForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralLoadPlanarForce::declaration() const { return *IFC4X3_RC2_IfcStructuralLoadPlanarForce_type; }
@@ -21868,17 +21868,17 @@ Ifc4x3_rc2::IfcStructuralLoadPlanarForce::IfcStructuralLoadPlanarForce(boost::op
 
 // Function implementations for IfcStructuralLoadSingleDisplacement
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::DisplacementX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::DisplacementY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::DisplacementZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::declaration() const { return *IFC4X3_RC2_IfcStructuralLoadSingleDisplacement_type; }
@@ -21888,7 +21888,7 @@ Ifc4x3_rc2::IfcStructuralLoadSingleDisplacement::IfcStructuralLoadSingleDisplace
 
 // Function implementations for IfcStructuralLoadSingleDisplacementDistortion
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleDisplacementDistortion::Distortion() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralLoadSingleDisplacementDistortion::declaration() const { return *IFC4X3_RC2_IfcStructuralLoadSingleDisplacementDistortion_type; }
@@ -21898,17 +21898,17 @@ Ifc4x3_rc2::IfcStructuralLoadSingleDisplacementDistortion::IfcStructuralLoadSing
 
 // Function implementations for IfcStructuralLoadSingleForce
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleForce::ForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleForce::ForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleForce::ForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleForce::MomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleForce::MomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleForce::MomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralLoadSingleForce::declaration() const { return *IFC4X3_RC2_IfcStructuralLoadSingleForce_type; }
@@ -21918,7 +21918,7 @@ Ifc4x3_rc2::IfcStructuralLoadSingleForce::IfcStructuralLoadSingleForce(boost::op
 
 // Function implementations for IfcStructuralLoadSingleForceWarping
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadSingleForceWarping::WarpingMoment() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralLoadSingleForceWarping::declaration() const { return *IFC4X3_RC2_IfcStructuralLoadSingleForceWarping_type; }
@@ -21936,11 +21936,11 @@ Ifc4x3_rc2::IfcStructuralLoadStatic::IfcStructuralLoadStatic(boost::optional< st
 
 // Function implementations for IfcStructuralLoadTemperature
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadTemperature::DeltaTConstant() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadTemperature::DeltaTY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralLoadTemperature::DeltaTZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralLoadTemperature::declaration() const { return *IFC4X3_RC2_IfcStructuralLoadTemperature_type; }
@@ -22016,7 +22016,7 @@ Ifc4x3_rc2::IfcStructuralResultGroup::IfcStructuralResultGroup(std::string v1_Gl
 
 // Function implementations for IfcStructuralSurfaceAction
 boost::optional< ::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::Value > Ifc4x3_rc2::IfcStructuralSurfaceAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc2::IfcStructuralSurfaceActivityTypeEnum::Value Ifc4x3_rc2::IfcStructuralSurfaceAction::PredefinedType() const {  return ::Ifc4x3_rc2::IfcStructuralSurfaceActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x3_rc2::IfcStructuralSurfaceAction::setPredefinedType(::Ifc4x3_rc2::IfcStructuralSurfaceActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcStructuralSurfaceActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -22038,7 +22038,7 @@ Ifc4x3_rc2::IfcStructuralSurfaceConnection::IfcStructuralSurfaceConnection(std::
 ::Ifc4x3_rc2::IfcStructuralSurfaceMemberTypeEnum::Value Ifc4x3_rc2::IfcStructuralSurfaceMember::PredefinedType() const {  return ::Ifc4x3_rc2::IfcStructuralSurfaceMemberTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc2::IfcStructuralSurfaceMember::setPredefinedType(::Ifc4x3_rc2::IfcStructuralSurfaceMemberTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcStructuralSurfaceMemberTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcStructuralSurfaceMember::Thickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStructuralSurfaceMember::declaration() const { return *IFC4X3_RC2_IfcStructuralSurfaceMember_type; }
@@ -22078,7 +22078,7 @@ void Ifc4x3_rc2::IfcStyledItem::setItem(::Ifc4x3_rc2::IfcRepresentationItem* v)
 aggregate_of_instance::ptr Ifc4x3_rc2::IfcStyledItem::Styles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcStyledItem::setStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcStyledItem::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcStyledItem::declaration() const { return *IFC4X3_RC2_IfcStyledItem_type; }
@@ -22096,7 +22096,7 @@ Ifc4x3_rc2::IfcStyledRepresentation::IfcStyledRepresentation(::Ifc4x3_rc2::IfcRe
 
 // Function implementations for IfcSubContractResource
 boost::optional< ::Ifc4x3_rc2::IfcSubContractResourceTypeEnum::Value > Ifc4x3_rc2::IfcSubContractResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSubContractResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSubContractResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSubContractResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSubContractResource::declaration() const { return *IFC4X3_RC2_IfcSubContractResource_type; }
@@ -22158,7 +22158,7 @@ Ifc4x3_rc2::IfcSurfaceCurveSweptAreaSolid::IfcSurfaceCurveSweptAreaSolid(::Ifc4x
 
 // Function implementations for IfcSurfaceFeature
 boost::optional< ::Ifc4x3_rc2::IfcSurfaceFeatureTypeEnum::Value > Ifc4x3_rc2::IfcSurfaceFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSurfaceFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSurfaceFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSurfaceFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSurfaceFeature::declaration() const { return *IFC4X3_RC2_IfcSurfaceFeature_type; }
@@ -22190,11 +22190,11 @@ Ifc4x3_rc2::IfcSurfaceOfRevolution::IfcSurfaceOfRevolution(::Ifc4x3_rc2::IfcProf
 
 // Function implementations for IfcSurfaceReinforcementArea
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x3_rc2::IfcSurfaceReinforcementArea::SurfaceReinforcement1() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x3_rc2::IfcSurfaceReinforcementArea::SurfaceReinforcement2() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSurfaceReinforcementArea::ShearReinforcement() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSurfaceReinforcementArea::declaration() const { return *IFC4X3_RC2_IfcSurfaceReinforcementArea_type; }
@@ -22232,9 +22232,9 @@ Ifc4x3_rc2::IfcSurfaceStyleLighting::IfcSurfaceStyleLighting(::Ifc4x3_rc2::IfcCo
 
 // Function implementations for IfcSurfaceStyleRefraction
 boost::optional< double > Ifc4x3_rc2::IfcSurfaceStyleRefraction::RefractionIndex() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSurfaceStyleRefraction::DispersionFactor() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSurfaceStyleRefraction::declaration() const { return *IFC4X3_RC2_IfcSurfaceStyleRefraction_type; }
@@ -22268,7 +22268,7 @@ Ifc4x3_rc2::IfcSurfaceStyleRendering::IfcSurfaceStyleRendering(::Ifc4x3_rc2::Ifc
 ::Ifc4x3_rc2::IfcColourRgb* Ifc4x3_rc2::IfcSurfaceStyleShading::SurfaceColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc2::IfcColourRgb>(true); }
 void Ifc4x3_rc2::IfcSurfaceStyleShading::setSurfaceColour(::Ifc4x3_rc2::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSurfaceStyleShading::Transparency() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSurfaceStyleShading::declaration() const { return *IFC4X3_RC2_IfcSurfaceStyleShading_type; }
@@ -22292,11 +22292,11 @@ void Ifc4x3_rc2::IfcSurfaceTexture::setRepeatS(bool v) { {IfcWrite::IfcWriteArgu
 bool Ifc4x3_rc2::IfcSurfaceTexture::RepeatT() const {  bool v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcSurfaceTexture::setRepeatT(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcSurfaceTexture::Mode() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcCartesianTransformationOperator2D* Ifc4x3_rc2::IfcSurfaceTexture::TextureTransform() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x3_rc2::IfcSurfaceTexture::setTextureTransform(::Ifc4x3_rc2::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcSurfaceTexture::Parameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc2::IfcTextureCoordinate::list::ptr Ifc4x3_rc2::IfcSurfaceTexture::IsMappedBy() const { return data_->getInverse(IFC4X3_RC2_IfcTextureCoordinate_type, 0)->as<IfcTextureCoordinate>(); }
 ::Ifc4x3_rc2::IfcSurfaceStyleWithTextures::list::ptr Ifc4x3_rc2::IfcSurfaceTexture::UsedInStyles() const { return data_->getInverse(IFC4X3_RC2_IfcSurfaceStyleWithTextures_type, 0)->as<IfcSurfaceStyleWithTextures>(); }
@@ -22324,11 +22324,11 @@ void Ifc4x3_rc2::IfcSweptDiskSolid::setDirectrix(::Ifc4x3_rc2::IfcCurve* v) { {I
 double Ifc4x3_rc2::IfcSweptDiskSolid::Radius() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcSweptDiskSolid::setRadius(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSweptDiskSolid::InnerRadius() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSweptDiskSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcSweptDiskSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSweptDiskSolid::declaration() const { return *IFC4X3_RC2_IfcSweptDiskSolid_type; }
@@ -22338,7 +22338,7 @@ Ifc4x3_rc2::IfcSweptDiskSolid::IfcSweptDiskSolid(::Ifc4x3_rc2::IfcCurve* v1_Dire
 
 // Function implementations for IfcSweptDiskSolidPolygonal
 boost::optional< double > Ifc4x3_rc2::IfcSweptDiskSolidPolygonal::FilletRadius() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSweptDiskSolidPolygonal::declaration() const { return *IFC4X3_RC2_IfcSweptDiskSolidPolygonal_type; }
@@ -22360,7 +22360,7 @@ Ifc4x3_rc2::IfcSweptSurface::IfcSweptSurface(::Ifc4x3_rc2::IfcProfileDef* v1_Swe
 
 // Function implementations for IfcSwitchingDevice
 boost::optional< ::Ifc4x3_rc2::IfcSwitchingDeviceTypeEnum::Value > Ifc4x3_rc2::IfcSwitchingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSwitchingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSwitchingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSwitchingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSwitchingDevice::declaration() const { return *IFC4X3_RC2_IfcSwitchingDevice_type; }
@@ -22390,7 +22390,7 @@ Ifc4x3_rc2::IfcSystem::IfcSystem(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwner
 
 // Function implementations for IfcSystemFurnitureElement
 boost::optional< ::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x3_rc2::IfcSystemFurnitureElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSystemFurnitureElement::declaration() const { return *IFC4X3_RC2_IfcSystemFurnitureElement_type; }
@@ -22400,7 +22400,7 @@ Ifc4x3_rc2::IfcSystemFurnitureElement::IfcSystemFurnitureElement(std::string v1_
 
 // Function implementations for IfcSystemFurnitureElementType
 boost::optional< ::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x3_rc2::IfcSystemFurnitureElementType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc2::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcSystemFurnitureElementType::declaration() const { return *IFC4X3_RC2_IfcSystemFurnitureElementType_type; }
@@ -22418,15 +22418,15 @@ void Ifc4x3_rc2::IfcTShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc2::IfcTShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcTShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTShapeProfileDef::WebEdgeRadius() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTShapeProfileDef::WebSlope() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTShapeProfileDef::declaration() const { return *IFC4X3_RC2_IfcTShapeProfileDef_type; }
@@ -22436,11 +22436,11 @@ Ifc4x3_rc2::IfcTShapeProfileDef::IfcTShapeProfileDef(::Ifc4x3_rc2::IfcProfileTyp
 
 // Function implementations for IfcTable
 boost::optional< std::string > Ifc4x3_rc2::IfcTable::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcTableRow >::ptr > Ifc4x3_rc2::IfcTable::Rows() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc2::IfcTableRow >(); }
-void Ifc4x3_rc2::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcTableColumn >::ptr > Ifc4x3_rc2::IfcTable::Columns() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc2::IfcTableColumn >(); }
-void Ifc4x3_rc2::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTable::declaration() const { return *IFC4X3_RC2_IfcTable_type; }
@@ -22450,11 +22450,11 @@ Ifc4x3_rc2::IfcTable::IfcTable(boost::optional< std::string > v1_Name, boost::op
 
 // Function implementations for IfcTableColumn
 boost::optional< std::string > Ifc4x3_rc2::IfcTableColumn::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTableColumn::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTableColumn::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcUnit* Ifc4x3_rc2::IfcTableColumn::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcUnit>(true); }
 void Ifc4x3_rc2::IfcTableColumn::setUnit(::Ifc4x3_rc2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc2::IfcReference* Ifc4x3_rc2::IfcTableColumn::ReferencePath() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc2::IfcReference>(true); }
@@ -22468,9 +22468,9 @@ Ifc4x3_rc2::IfcTableColumn::IfcTableColumn(boost::optional< std::string > v1_Ide
 
 // Function implementations for IfcTableRow
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc2::IfcTableRow::RowCells() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc2::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc2::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< bool > Ifc4x3_rc2::IfcTableRow::IsHeading() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTableRow::declaration() const { return *IFC4X3_RC2_IfcTableRow_type; }
@@ -22480,7 +22480,7 @@ Ifc4x3_rc2::IfcTableRow::IfcTableRow(boost::optional< aggregate_of_instance::ptr
 
 // Function implementations for IfcTank
 boost::optional< ::Ifc4x3_rc2::IfcTankTypeEnum::Value > Ifc4x3_rc2::IfcTank::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcTankTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcTank::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTankTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcTank::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTankTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTank::declaration() const { return *IFC4X3_RC2_IfcTank_type; }
@@ -22500,17 +22500,17 @@ Ifc4x3_rc2::IfcTankType::IfcTankType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcTask
 boost::optional< std::string > Ifc4x3_rc2::IfcTask::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTask::WorkMethod() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 bool Ifc4x3_rc2::IfcTask::IsMilestone() const {  bool v = *data_->getArgument(9); return v; }
 void Ifc4x3_rc2::IfcTask::setIsMilestone(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< int > Ifc4x3_rc2::IfcTask::Priority() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } int v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc2::IfcTaskTime* Ifc4x3_rc2::IfcTask::TaskTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc2::IfcTaskTime>(true); }
 void Ifc4x3_rc2::IfcTask::setTaskTime(::Ifc4x3_rc2::IfcTaskTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcTaskTypeEnum::Value > Ifc4x3_rc2::IfcTask::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcTaskTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc2::IfcTask::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTaskTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcTask::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTaskTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTask::declaration() const { return *IFC4X3_RC2_IfcTask_type; }
@@ -22520,39 +22520,39 @@ Ifc4x3_rc2::IfcTask::IfcTask(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwnerHist
 
 // Function implementations for IfcTaskTime
 boost::optional< ::Ifc4x3_rc2::IfcTaskDurationEnum::Value > Ifc4x3_rc2::IfcTaskTime::DurationType() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcTaskDurationEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x3_rc2::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x3_rc2::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTaskDurationEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x3_rc2::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTaskDurationEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::ScheduleDuration() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::EarlyStart() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::EarlyFinish() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::LateStart() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::LateFinish() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::FreeFloat() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::TotalFloat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< bool > Ifc4x3_rc2::IfcTaskTime::IsCritical() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } bool v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::StatusTime() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::ActualDuration() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::ActualStart() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } std::string v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::ActualFinish() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } std::string v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskTime::RemainingTime() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTaskTime::Completion() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } double v = *data_->getArgument(19); return v; }
-void Ifc4x3_rc2::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x3_rc2::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTaskTime::declaration() const { return *IFC4X3_RC2_IfcTaskTime_type; }
@@ -22574,7 +22574,7 @@ Ifc4x3_rc2::IfcTaskTimeRecurring::IfcTaskTimeRecurring(boost::optional< std::str
 ::Ifc4x3_rc2::IfcTaskTypeEnum::Value Ifc4x3_rc2::IfcTaskType::PredefinedType() const {  return ::Ifc4x3_rc2::IfcTaskTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc2::IfcTaskType::setPredefinedType(::Ifc4x3_rc2::IfcTaskTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcTaskTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTaskType::WorkMethod() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTaskType::declaration() const { return *IFC4X3_RC2_IfcTaskType_type; }
@@ -22584,17 +22584,17 @@ Ifc4x3_rc2::IfcTaskType::IfcTaskType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcTelecomAddress
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcTelecomAddress::TelephoneNumbers() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcTelecomAddress::FacsimileNumbers() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTelecomAddress::PagerNumber() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcTelecomAddress::ElectronicMailAddresses() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTelecomAddress::WWWHomePageURL() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc2::IfcTelecomAddress::MessagingIDs() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTelecomAddress::declaration() const { return *IFC4X3_RC2_IfcTelecomAddress_type; }
@@ -22604,21 +22604,21 @@ Ifc4x3_rc2::IfcTelecomAddress::IfcTelecomAddress(boost::optional< ::Ifc4x3_rc2::
 
 // Function implementations for IfcTendon
 boost::optional< ::Ifc4x3_rc2::IfcTendonTypeEnum::Value > Ifc4x3_rc2::IfcTendon::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc2::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTendonTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTendonTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTendon::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTendon::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTendon::TensionForce() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTendon::PreStress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc2::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTendon::FrictionCoefficient() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc2::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc2::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTendon::AnchorageSlip() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc2::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc2::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTendon::MinCurvatureRadius() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc2::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc2::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTendon::declaration() const { return *IFC4X3_RC2_IfcTendon_type; }
@@ -22628,7 +22628,7 @@ Ifc4x3_rc2::IfcTendon::IfcTendon(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwner
 
 // Function implementations for IfcTendonAnchor
 boost::optional< ::Ifc4x3_rc2::IfcTendonAnchorTypeEnum::Value > Ifc4x3_rc2::IfcTendonAnchor::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcTendonAnchorTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc2::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTendonAnchorTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTendonAnchorTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTendonAnchor::declaration() const { return *IFC4X3_RC2_IfcTendonAnchor_type; }
@@ -22670,11 +22670,11 @@ Ifc4x3_rc2::IfcTendonConduitType::IfcTendonConduitType(std::string v1_GlobalId,
 ::Ifc4x3_rc2::IfcTendonTypeEnum::Value Ifc4x3_rc2::IfcTendonType::PredefinedType() const {  return ::Ifc4x3_rc2::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc2::IfcTendonType::setPredefinedType(::Ifc4x3_rc2::IfcTendonTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcTendonTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTendonType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTendonType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTendonType::SheathDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTendonType::declaration() const { return *IFC4X3_RC2_IfcTendonType_type; }
@@ -22736,7 +22736,7 @@ void Ifc4x3_rc2::IfcTextStyle::setTextStyle(::Ifc4x3_rc2::IfcTextStyleTextModel*
 ::Ifc4x3_rc2::IfcTextFontSelect* Ifc4x3_rc2::IfcTextStyle::TextFontStyle() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcTextFontSelect>(true); }
 void Ifc4x3_rc2::IfcTextStyle::setTextFontStyle(::Ifc4x3_rc2::IfcTextFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x3_rc2::IfcTextStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTextStyle::declaration() const { return *IFC4X3_RC2_IfcTextStyle_type; }
@@ -22748,11 +22748,11 @@ Ifc4x3_rc2::IfcTextStyle::IfcTextStyle(boost::optional< std::string > v1_Name, :
 std::vector< std::string > /*[1:?]*/ Ifc4x3_rc2::IfcTextStyleFontModel::FontFamily() const {  std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcTextStyleFontModel::setFontFamily(std::vector< std::string > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTextStyleFontModel::FontStyle() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTextStyleFontModel::FontVariant() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTextStyleFontModel::FontWeight() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc2::IfcSizeSelect* Ifc4x3_rc2::IfcTextStyleFontModel::FontSize() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc2::IfcSizeSelect>(true); }
 void Ifc4x3_rc2::IfcTextStyleFontModel::setFontSize(::Ifc4x3_rc2::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -22778,15 +22778,15 @@ Ifc4x3_rc2::IfcTextStyleForDefinedFont::IfcTextStyleForDefinedFont(::Ifc4x3_rc2:
 ::Ifc4x3_rc2::IfcSizeSelect* Ifc4x3_rc2::IfcTextStyleTextModel::TextIndent() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc2::IfcSizeSelect>(true); }
 void Ifc4x3_rc2::IfcTextStyleTextModel::setTextIndent(::Ifc4x3_rc2::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTextStyleTextModel::TextAlign() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTextStyleTextModel::TextDecoration() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc2::IfcSizeSelect* Ifc4x3_rc2::IfcTextStyleTextModel::LetterSpacing() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcSizeSelect>(true); }
 void Ifc4x3_rc2::IfcTextStyleTextModel::setLetterSpacing(::Ifc4x3_rc2::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc2::IfcSizeSelect* Ifc4x3_rc2::IfcTextStyleTextModel::WordSpacing() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc2::IfcSizeSelect>(true); }
 void Ifc4x3_rc2::IfcTextStyleTextModel::setWordSpacing(::Ifc4x3_rc2::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTextStyleTextModel::TextTransform() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc2::IfcSizeSelect* Ifc4x3_rc2::IfcTextStyleTextModel::LineHeight() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc2::IfcSizeSelect>(true); }
 void Ifc4x3_rc2::IfcTextStyleTextModel::setLineHeight(::Ifc4x3_rc2::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -22810,7 +22810,7 @@ Ifc4x3_rc2::IfcTextureCoordinate::IfcTextureCoordinate(aggregate_of< ::Ifc4x3_rc
 std::string Ifc4x3_rc2::IfcTextureCoordinateGenerator::Mode() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc2::IfcTextureCoordinateGenerator::setMode(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[1:?]*/ > Ifc4x3_rc2::IfcTextureCoordinateGenerator::Parameter() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTextureCoordinateGenerator::declaration() const { return *IFC4X3_RC2_IfcTextureCoordinateGenerator_type; }
@@ -22866,7 +22866,7 @@ Ifc4x3_rc2::IfcTimePeriod::IfcTimePeriod(std::string v1_StartTime, std::string v
 std::string Ifc4x3_rc2::IfcTimeSeries::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc2::IfcTimeSeries::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTimeSeries::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 std::string Ifc4x3_rc2::IfcTimeSeries::StartTime() const {  std::string v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc2::IfcTimeSeries::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::string Ifc4x3_rc2::IfcTimeSeries::EndTime() const {  std::string v = *data_->getArgument(3); return v; }
@@ -22876,7 +22876,7 @@ void Ifc4x3_rc2::IfcTimeSeries::setTimeSeriesDataType(::Ifc4x3_rc2::IfcTimeSerie
 ::Ifc4x3_rc2::IfcDataOriginEnum::Value Ifc4x3_rc2::IfcTimeSeries::DataOrigin() const {  return ::Ifc4x3_rc2::IfcDataOriginEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc2::IfcTimeSeries::setDataOrigin(::Ifc4x3_rc2::IfcDataOriginEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcDataOriginEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTimeSeries::UserDefinedDataOrigin() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc2::IfcUnit* Ifc4x3_rc2::IfcTimeSeries::Unit() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc2::IfcUnit>(true); }
 void Ifc4x3_rc2::IfcTimeSeries::setUnit(::Ifc4x3_rc2::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 
@@ -22927,7 +22927,7 @@ Ifc4x3_rc2::IfcToroidalSurface::IfcToroidalSurface(::Ifc4x3_rc2::IfcAxis2Placeme
 
 // Function implementations for IfcTrackElement
 boost::optional< ::Ifc4x3_rc2::IfcTrackElementTypeEnum::Value > Ifc4x3_rc2::IfcTrackElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcTrackElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcTrackElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTrackElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTrackElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcTrackElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTrackElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTrackElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTrackElement::declaration() const { return *IFC4X3_RC2_IfcTrackElement_type; }
@@ -22947,7 +22947,7 @@ Ifc4x3_rc2::IfcTrackElementType::IfcTrackElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcTransformer
 boost::optional< ::Ifc4x3_rc2::IfcTransformerTypeEnum::Value > Ifc4x3_rc2::IfcTransformer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcTransformerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTransformerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTransformerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTransformer::declaration() const { return *IFC4X3_RC2_IfcTransformer_type; }
@@ -22967,9 +22967,9 @@ Ifc4x3_rc2::IfcTransformerType::IfcTransformerType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcTransitionCurveSegment2D
 boost::optional< double > Ifc4x3_rc2::IfcTransitionCurveSegment2D::StartRadius() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc2::IfcTransitionCurveSegment2D::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc2::IfcTransitionCurveSegment2D::setStartRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcTransitionCurveSegment2D::EndRadius() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcTransitionCurveSegment2D::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcTransitionCurveSegment2D::setEndRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 bool Ifc4x3_rc2::IfcTransitionCurveSegment2D::IsStartRadiusCCW() const {  bool v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc2::IfcTransitionCurveSegment2D::setIsStartRadiusCCW(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 bool Ifc4x3_rc2::IfcTransitionCurveSegment2D::IsEndRadiusCCW() const {  bool v = *data_->getArgument(6); return v; }
@@ -23021,13 +23021,13 @@ Ifc4x3_rc2::IfcTrapeziumProfileDef::IfcTrapeziumProfileDef(::Ifc4x3_rc2::IfcProf
 
 // Function implementations for IfcTriangulatedFaceSet
 boost::optional< std::vector< std::vector< double > > > Ifc4x3_rc2::IfcTriangulatedFaceSet::Normals() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc2::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc2::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc2::IfcTriangulatedFaceSet::Closed() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc2::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc2::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::vector< std::vector< int > > Ifc4x3_rc2::IfcTriangulatedFaceSet::CoordIndex() const {  std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc2::IfcTriangulatedFaceSet::setCoordIndex(std::vector< std::vector< int > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc2::IfcTriangulatedFaceSet::PnIndex() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTriangulatedFaceSet::declaration() const { return *IFC4X3_RC2_IfcTriangulatedFaceSet_type; }
@@ -23065,7 +23065,7 @@ Ifc4x3_rc2::IfcTrimmedCurve::IfcTrimmedCurve(::Ifc4x3_rc2::IfcCurve* v1_BasisCur
 
 // Function implementations for IfcTubeBundle
 boost::optional< ::Ifc4x3_rc2::IfcTubeBundleTypeEnum::Value > Ifc4x3_rc2::IfcTubeBundle::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcTubeBundleTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTubeBundleTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcTubeBundleTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcTubeBundle::declaration() const { return *IFC4X3_RC2_IfcTubeBundle_type; }
@@ -23085,9 +23085,9 @@ Ifc4x3_rc2::IfcTubeBundleType::IfcTubeBundleType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcTypeObject
 boost::optional< std::string > Ifc4x3_rc2::IfcTypeObject::ApplicableOccurrence() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPropertySetDefinition >::ptr > Ifc4x3_rc2::IfcTypeObject::HasPropertySets() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc2::IfcPropertySetDefinition >(); }
-void Ifc4x3_rc2::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc2::IfcRelDefinesByType::list::ptr Ifc4x3_rc2::IfcTypeObject::Types() const { return data_->getInverse(IFC4X3_RC2_IfcRelDefinesByType_type, 5)->as<IfcRelDefinesByType>(); }
 
@@ -23098,11 +23098,11 @@ Ifc4x3_rc2::IfcTypeObject::IfcTypeObject(std::string v1_GlobalId, ::Ifc4x3_rc2::
 
 // Function implementations for IfcTypeProcess
 boost::optional< std::string > Ifc4x3_rc2::IfcTypeProcess::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTypeProcess::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTypeProcess::ProcessType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc2::IfcRelAssignsToProcess::list::ptr Ifc4x3_rc2::IfcTypeProcess::OperatesOn() const { return data_->getInverse(IFC4X3_RC2_IfcRelAssignsToProcess_type, 6)->as<IfcRelAssignsToProcess>(); }
 
@@ -23113,9 +23113,9 @@ Ifc4x3_rc2::IfcTypeProcess::IfcTypeProcess(std::string v1_GlobalId, ::Ifc4x3_rc2
 
 // Function implementations for IfcTypeProduct
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcRepresentationMap >::ptr > Ifc4x3_rc2::IfcTypeProduct::RepresentationMaps() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc2::IfcRepresentationMap >(); }
-void Ifc4x3_rc2::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTypeProduct::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc2::IfcRelAssignsToProduct::list::ptr Ifc4x3_rc2::IfcTypeProduct::ReferencedBy() const { return data_->getInverse(IFC4X3_RC2_IfcRelAssignsToProduct_type, 6)->as<IfcRelAssignsToProduct>(); }
 
@@ -23126,11 +23126,11 @@ Ifc4x3_rc2::IfcTypeProduct::IfcTypeProduct(std::string v1_GlobalId, ::Ifc4x3_rc2
 
 // Function implementations for IfcTypeResource
 boost::optional< std::string > Ifc4x3_rc2::IfcTypeResource::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTypeResource::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcTypeResource::ResourceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc2::IfcRelAssignsToResource::list::ptr Ifc4x3_rc2::IfcTypeResource::ResourceOf() const { return data_->getInverse(IFC4X3_RC2_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -23149,11 +23149,11 @@ void Ifc4x3_rc2::IfcUShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc2::IfcUShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcUShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcUShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcUShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcUShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcUShapeProfileDef::declaration() const { return *IFC4X3_RC2_IfcUShapeProfileDef_type; }
@@ -23173,7 +23173,7 @@ Ifc4x3_rc2::IfcUnitAssignment::IfcUnitAssignment(aggregate_of_instance::ptr v1_U
 
 // Function implementations for IfcUnitaryControlElement
 boost::optional< ::Ifc4x3_rc2::IfcUnitaryControlElementTypeEnum::Value > Ifc4x3_rc2::IfcUnitaryControlElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcUnitaryControlElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcUnitaryControlElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcUnitaryControlElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcUnitaryControlElement::declaration() const { return *IFC4X3_RC2_IfcUnitaryControlElement_type; }
@@ -23193,7 +23193,7 @@ Ifc4x3_rc2::IfcUnitaryControlElementType::IfcUnitaryControlElementType(std::stri
 
 // Function implementations for IfcUnitaryEquipment
 boost::optional< ::Ifc4x3_rc2::IfcUnitaryEquipmentTypeEnum::Value > Ifc4x3_rc2::IfcUnitaryEquipment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcUnitaryEquipmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcUnitaryEquipmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcUnitaryEquipmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcUnitaryEquipment::declaration() const { return *IFC4X3_RC2_IfcUnitaryEquipment_type; }
@@ -23213,7 +23213,7 @@ Ifc4x3_rc2::IfcUnitaryEquipmentType::IfcUnitaryEquipmentType(std::string v1_Glob
 
 // Function implementations for IfcValve
 boost::optional< ::Ifc4x3_rc2::IfcValveTypeEnum::Value > Ifc4x3_rc2::IfcValve::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcValveTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcValve::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcValveTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcValve::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcValveTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcValve::declaration() const { return *IFC4X3_RC2_IfcValve_type; }
@@ -23273,7 +23273,7 @@ Ifc4x3_rc2::IfcVertexPoint::IfcVertexPoint(::Ifc4x3_rc2::IfcPoint* v1_VertexGeom
 
 // Function implementations for IfcVibrationDamper
 boost::optional< ::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::Value > Ifc4x3_rc2::IfcVibrationDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcVibrationDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcVibrationDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcVibrationDamper::declaration() const { return *IFC4X3_RC2_IfcVibrationDamper_type; }
@@ -23283,7 +23283,7 @@ Ifc4x3_rc2::IfcVibrationDamper::IfcVibrationDamper(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcVibrationDamperType
 boost::optional< ::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::Value > Ifc4x3_rc2::IfcVibrationDamperType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc2::IfcVibrationDamperType::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcVibrationDamperType::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcVibrationDamperTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcVibrationDamperType::declaration() const { return *IFC4X3_RC2_IfcVibrationDamperType_type; }
@@ -23293,7 +23293,7 @@ Ifc4x3_rc2::IfcVibrationDamperType::IfcVibrationDamperType(std::string v1_Global
 
 // Function implementations for IfcVibrationIsolator
 boost::optional< ::Ifc4x3_rc2::IfcVibrationIsolatorTypeEnum::Value > Ifc4x3_rc2::IfcVibrationIsolator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcVibrationIsolatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcVibrationIsolatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcVibrationIsolatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcVibrationIsolator::declaration() const { return *IFC4X3_RC2_IfcVibrationIsolator_type; }
@@ -23341,7 +23341,7 @@ Ifc4x3_rc2::IfcVoidStratum::IfcVoidStratum(std::string v1_GlobalId, ::Ifc4x3_rc2
 
 // Function implementations for IfcVoidingFeature
 boost::optional< ::Ifc4x3_rc2::IfcVoidingFeatureTypeEnum::Value > Ifc4x3_rc2::IfcVoidingFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcVoidingFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcVoidingFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcVoidingFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcVoidingFeature::declaration() const { return *IFC4X3_RC2_IfcVoidingFeature_type; }
@@ -23351,7 +23351,7 @@ Ifc4x3_rc2::IfcVoidingFeature::IfcVoidingFeature(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcWall
 boost::optional< ::Ifc4x3_rc2::IfcWallTypeEnum::Value > Ifc4x3_rc2::IfcWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcWall::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcWall::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcWall::declaration() const { return *IFC4X3_RC2_IfcWall_type; }
@@ -23387,7 +23387,7 @@ Ifc4x3_rc2::IfcWallType::IfcWallType(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcWasteTerminal
 boost::optional< ::Ifc4x3_rc2::IfcWasteTerminalTypeEnum::Value > Ifc4x3_rc2::IfcWasteTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcWasteTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWasteTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWasteTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcWasteTerminal::declaration() const { return *IFC4X3_RC2_IfcWasteTerminal_type; }
@@ -23415,15 +23415,15 @@ Ifc4x3_rc2::IfcWaterStratum::IfcWaterStratum(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcWindow
 boost::optional< double > Ifc4x3_rc2::IfcWindow::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindow::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcWindowTypeEnum::Value > Ifc4x3_rc2::IfcWindow::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcWindowTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc2::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWindowTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWindowTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcWindowTypePartitioningEnum::Value > Ifc4x3_rc2::IfcWindow::PartitioningType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc2::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x3_rc2::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWindowTypePartitioningEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x3_rc2::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWindowTypePartitioningEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcWindow::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcWindow::declaration() const { return *IFC4X3_RC2_IfcWindow_type; }
@@ -23433,29 +23433,29 @@ Ifc4x3_rc2::IfcWindow::IfcWindow(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcOwner
 
 // Function implementations for IfcWindowLiningProperties
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::TransomThickness() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::MullionThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::FirstTransomOffset() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::SecondTransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::FirstMullionOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::SecondMullionOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 ::Ifc4x3_rc2::IfcShapeAspect* Ifc4x3_rc2::IfcWindowLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(12)))->as<::Ifc4x3_rc2::IfcShapeAspect>(true); }
 void Ifc4x3_rc2::IfcWindowLiningProperties::setShapeAspectStyle(::Ifc4x3_rc2::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::LiningOffset() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc2::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc2::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcWindowLiningProperties::declaration() const { return *IFC4X3_RC2_IfcWindowLiningProperties_type; }
@@ -23469,9 +23469,9 @@ void Ifc4x3_rc2::IfcWindowPanelProperties::setOperationType(::Ifc4x3_rc2::IfcWin
 ::Ifc4x3_rc2::IfcWindowPanelPositionEnum::Value Ifc4x3_rc2::IfcWindowPanelProperties::PanelPosition() const {  return ::Ifc4x3_rc2::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc2::IfcWindowPanelProperties::setPanelPosition(::Ifc4x3_rc2::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowPanelProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc2::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcWindowPanelProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc2::IfcShapeAspect* Ifc4x3_rc2::IfcWindowPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc2::IfcShapeAspect>(true); }
 void Ifc4x3_rc2::IfcWindowPanelProperties::setShapeAspectStyle(::Ifc4x3_rc2::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -23511,9 +23511,9 @@ void Ifc4x3_rc2::IfcWindowType::setPredefinedType(::Ifc4x3_rc2::IfcWindowTypeEnu
 ::Ifc4x3_rc2::IfcWindowTypePartitioningEnum::Value Ifc4x3_rc2::IfcWindowType::PartitioningType() const {  return ::Ifc4x3_rc2::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc2::IfcWindowType::setPartitioningType(::Ifc4x3_rc2::IfcWindowTypePartitioningEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc2::IfcWindowTypePartitioningEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x3_rc2::IfcWindowType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc2::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc2::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcWindowType::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcWindowType::declaration() const { return *IFC4X3_RC2_IfcWindowType_type; }
@@ -23523,11 +23523,11 @@ Ifc4x3_rc2::IfcWindowType::IfcWindowType(std::string v1_GlobalId, ::Ifc4x3_rc2::
 
 // Function implementations for IfcWorkCalendar
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcWorkTime >::ptr > Ifc4x3_rc2::IfcWorkCalendar::WorkingTimes() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc2::IfcWorkTime >(); }
-void Ifc4x3_rc2::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc2::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcWorkTime >::ptr > Ifc4x3_rc2::IfcWorkCalendar::ExceptionTimes() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc2::IfcWorkTime >(); }
-void Ifc4x3_rc2::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc2::IfcWorkCalendarTypeEnum::Value > Ifc4x3_rc2::IfcWorkCalendar::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcWorkCalendarTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc2::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWorkCalendarTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWorkCalendarTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcWorkCalendar::declaration() const { return *IFC4X3_RC2_IfcWorkCalendar_type; }
@@ -23539,17 +23539,17 @@ Ifc4x3_rc2::IfcWorkCalendar::IfcWorkCalendar(std::string v1_GlobalId, ::Ifc4x3_r
 std::string Ifc4x3_rc2::IfcWorkControl::CreationDate() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcWorkControl::setCreationDate(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPerson >::ptr > Ifc4x3_rc2::IfcWorkControl::Creators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc2::IfcPerson >(); }
-void Ifc4x3_rc2::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x3_rc2::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcWorkControl::Purpose() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcWorkControl::Duration() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc2::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc2::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcWorkControl::TotalFloat() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc2::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc2::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 std::string Ifc4x3_rc2::IfcWorkControl::StartTime() const {  std::string v = *data_->getArgument(11); return v; }
 void Ifc4x3_rc2::IfcWorkControl::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcWorkControl::FinishTime() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc2::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc2::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcWorkControl::declaration() const { return *IFC4X3_RC2_IfcWorkControl_type; }
@@ -23559,7 +23559,7 @@ Ifc4x3_rc2::IfcWorkControl::IfcWorkControl(std::string v1_GlobalId, ::Ifc4x3_rc2
 
 // Function implementations for IfcWorkPlan
 boost::optional< ::Ifc4x3_rc2::IfcWorkPlanTypeEnum::Value > Ifc4x3_rc2::IfcWorkPlan::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcWorkPlanTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc2::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWorkPlanTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWorkPlanTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcWorkPlan::declaration() const { return *IFC4X3_RC2_IfcWorkPlan_type; }
@@ -23569,7 +23569,7 @@ Ifc4x3_rc2::IfcWorkPlan::IfcWorkPlan(std::string v1_GlobalId, ::Ifc4x3_rc2::IfcO
 
 // Function implementations for IfcWorkSchedule
 boost::optional< ::Ifc4x3_rc2::IfcWorkScheduleTypeEnum::Value > Ifc4x3_rc2::IfcWorkSchedule::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc2::IfcWorkScheduleTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc2::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWorkScheduleTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc2::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc2::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc2::IfcWorkScheduleTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcWorkSchedule::declaration() const { return *IFC4X3_RC2_IfcWorkSchedule_type; }
@@ -23581,9 +23581,9 @@ Ifc4x3_rc2::IfcWorkSchedule::IfcWorkSchedule(std::string v1_GlobalId, ::Ifc4x3_r
 ::Ifc4x3_rc2::IfcRecurrencePattern* Ifc4x3_rc2::IfcWorkTime::RecurrencePattern() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc2::IfcRecurrencePattern>(true); }
 void Ifc4x3_rc2::IfcWorkTime::setRecurrencePattern(::Ifc4x3_rc2::IfcRecurrencePattern* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcWorkTime::Start() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc2::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc2::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc2::IfcWorkTime::Finish() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcWorkTime::declaration() const { return *IFC4X3_RC2_IfcWorkTime_type; }
@@ -23601,9 +23601,9 @@ void Ifc4x3_rc2::IfcZShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc2::IfcZShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc2::IfcZShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcZShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc2::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc2::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc2::IfcZShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc2::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc2::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcZShapeProfileDef::declaration() const { return *IFC4X3_RC2_IfcZShapeProfileDef_type; }
@@ -23613,7 +23613,7 @@ Ifc4x3_rc2::IfcZShapeProfileDef::IfcZShapeProfileDef(::Ifc4x3_rc2::IfcProfileTyp
 
 // Function implementations for IfcZone
 boost::optional< std::string > Ifc4x3_rc2::IfcZone::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc2::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc2::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc2::IfcZone::declaration() const { return *IFC4X3_RC2_IfcZone_type; }
diff --git a/src/ifcparse/Ifc4x3_rc3.cpp b/src/ifcparse/Ifc4x3_rc3.cpp
index 70e25bb91c..3733a9ede0 100644
--- a/src/ifcparse/Ifc4x3_rc3.cpp
+++ b/src/ifcparse/Ifc4x3_rc3.cpp
@@ -13130,11 +13130,11 @@ Ifc4x3_rc3::IfcWarpingMomentMeasure::operator double() const { return *data_->ge
 
 // Function implementations for IfcActionRequest
 boost::optional< ::Ifc4x3_rc3::IfcActionRequestTypeEnum::Value > Ifc4x3_rc3::IfcActionRequest::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcActionRequestTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc3::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcActionRequestTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcActionRequestTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcActionRequest::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcActionRequest::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcActionRequest::declaration() const { return *IFC4X3_RC3_IfcActionRequest_type; }
@@ -13157,9 +13157,9 @@ Ifc4x3_rc3::IfcActor::IfcActor(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHi
 ::Ifc4x3_rc3::IfcRoleEnum::Value Ifc4x3_rc3::IfcActorRole::Role() const {  return ::Ifc4x3_rc3::IfcRoleEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc3::IfcActorRole::setRole(::Ifc4x3_rc3::IfcRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcRoleEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcActorRole::UserDefinedRole() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcActorRole::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc3::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc3::IfcActorRole::HasExternalReference() const { return data_->getInverse(IFC4X3_RC3_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -13170,7 +13170,7 @@ Ifc4x3_rc3::IfcActorRole::IfcActorRole(::Ifc4x3_rc3::IfcRoleEnum::Value v1_Role,
 
 // Function implementations for IfcActuator
 boost::optional< ::Ifc4x3_rc3::IfcActuatorTypeEnum::Value > Ifc4x3_rc3::IfcActuator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcActuatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcActuatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcActuatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcActuator::declaration() const { return *IFC4X3_RC3_IfcActuator_type; }
@@ -13190,11 +13190,11 @@ Ifc4x3_rc3::IfcActuatorType::IfcActuatorType(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcAddress
 boost::optional< ::Ifc4x3_rc3::IfcAddressTypeEnum::Value > Ifc4x3_rc3::IfcAddress::Purpose() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcAddressTypeEnum::FromString(*data_->getArgument(0)); }
-void Ifc4x3_rc3::IfcAddress::setPurpose(boost::optional< ::Ifc4x3_rc3::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAddressTypeEnum::ToString(*v)));data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcAddress::setPurpose(boost::optional< ::Ifc4x3_rc3::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAddressTypeEnum::ToString(*v)));}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcAddress::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcAddress::UserDefinedPurpose() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc3::IfcPerson::list::ptr Ifc4x3_rc3::IfcAddress::OfPerson() const { return data_->getInverse(IFC4X3_RC3_IfcPerson_type, 7)->as<IfcPerson>(); }
 ::Ifc4x3_rc3::IfcOrganization::list::ptr Ifc4x3_rc3::IfcAddress::OfOrganization() const { return data_->getInverse(IFC4X3_RC3_IfcOrganization_type, 4)->as<IfcOrganization>(); }
@@ -13232,7 +13232,7 @@ Ifc4x3_rc3::IfcAdvancedFace::IfcAdvancedFace(aggregate_of< ::Ifc4x3_rc3::IfcFace
 
 // Function implementations for IfcAirTerminal
 boost::optional< ::Ifc4x3_rc3::IfcAirTerminalTypeEnum::Value > Ifc4x3_rc3::IfcAirTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcAirTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAirTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAirTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcAirTerminal::declaration() const { return *IFC4X3_RC3_IfcAirTerminal_type; }
@@ -13242,7 +13242,7 @@ Ifc4x3_rc3::IfcAirTerminal::IfcAirTerminal(std::string v1_GlobalId, ::Ifc4x3_rc3
 
 // Function implementations for IfcAirTerminalBox
 boost::optional< ::Ifc4x3_rc3::IfcAirTerminalBoxTypeEnum::Value > Ifc4x3_rc3::IfcAirTerminalBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcAirTerminalBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAirTerminalBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAirTerminalBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcAirTerminalBox::declaration() const { return *IFC4X3_RC3_IfcAirTerminalBox_type; }
@@ -13272,7 +13272,7 @@ Ifc4x3_rc3::IfcAirTerminalType::IfcAirTerminalType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcAirToAirHeatRecovery
 boost::optional< ::Ifc4x3_rc3::IfcAirToAirHeatRecoveryTypeEnum::Value > Ifc4x3_rc3::IfcAirToAirHeatRecovery::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcAirToAirHeatRecoveryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcAirToAirHeatRecovery::declaration() const { return *IFC4X3_RC3_IfcAirToAirHeatRecovery_type; }
@@ -13292,7 +13292,7 @@ Ifc4x3_rc3::IfcAirToAirHeatRecoveryType::IfcAirToAirHeatRecoveryType(std::string
 
 // Function implementations for IfcAlarm
 boost::optional< ::Ifc4x3_rc3::IfcAlarmTypeEnum::Value > Ifc4x3_rc3::IfcAlarm::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcAlarmTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAlarmTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAlarmTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcAlarm::declaration() const { return *IFC4X3_RC3_IfcAlarm_type; }
@@ -13312,7 +13312,7 @@ Ifc4x3_rc3::IfcAlarmType::IfcAlarmType(std::string v1_GlobalId, ::Ifc4x3_rc3::If
 
 // Function implementations for IfcAlignment
 boost::optional< ::Ifc4x3_rc3::IfcAlignmentTypeEnum::Value > Ifc4x3_rc3::IfcAlignment::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcAlignmentTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc3::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAlignmentTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAlignmentTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcAlignment::declaration() const { return *IFC4X3_RC3_IfcAlignment_type; }
@@ -13338,11 +13338,11 @@ void Ifc4x3_rc3::IfcAlignmentCantSegment::setHorizontalLength(double v) { {IfcWr
 double Ifc4x3_rc3::IfcAlignmentCantSegment::StartCantLeft() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc3::IfcAlignmentCantSegment::setStartCantLeft(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAlignmentCantSegment::EndCantLeft() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcAlignmentCantSegment::setEndCantLeft(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcAlignmentCantSegment::setEndCantLeft(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 double Ifc4x3_rc3::IfcAlignmentCantSegment::StartCantRight() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcAlignmentCantSegment::setStartCantRight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAlignmentCantSegment::EndCantRight() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcAlignmentCantSegment::setEndCantRight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcAlignmentCantSegment::setEndCantRight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcAlignmentCantSegmentTypeEnum::Value Ifc4x3_rc3::IfcAlignmentCantSegment::PredefinedType() const {  return ::Ifc4x3_rc3::IfcAlignmentCantSegmentTypeEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc3::IfcAlignmentCantSegment::setPredefinedType(::Ifc4x3_rc3::IfcAlignmentCantSegmentTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcAlignmentCantSegmentTypeEnum::ToString(v)));data_->setArgument(8,attr);} }
 
@@ -13372,7 +13372,7 @@ void Ifc4x3_rc3::IfcAlignmentHorizontalSegment::setEndRadiusOfCurvature(double v
 double Ifc4x3_rc3::IfcAlignmentHorizontalSegment::SegmentLength() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcAlignmentHorizontalSegment::setSegmentLength(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAlignmentHorizontalSegment::GravityCenterLineHeight() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcAlignmentHorizontalSegment::setGravityCenterLineHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcAlignmentHorizontalSegment::setGravityCenterLineHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcAlignmentHorizontalSegmentTypeEnum::Value Ifc4x3_rc3::IfcAlignmentHorizontalSegment::PredefinedType() const {  return ::Ifc4x3_rc3::IfcAlignmentHorizontalSegmentTypeEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc3::IfcAlignmentHorizontalSegment::setPredefinedType(::Ifc4x3_rc3::IfcAlignmentHorizontalSegmentTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcAlignmentHorizontalSegmentTypeEnum::ToString(v)));data_->setArgument(8,attr);} }
 
@@ -13384,9 +13384,9 @@ Ifc4x3_rc3::IfcAlignmentHorizontalSegment::IfcAlignmentHorizontalSegment(boost::
 
 // Function implementations for IfcAlignmentParameterSegment
 boost::optional< std::string > Ifc4x3_rc3::IfcAlignmentParameterSegment::StartTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcAlignmentParameterSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcAlignmentParameterSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcAlignmentParameterSegment::EndTag() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcAlignmentParameterSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcAlignmentParameterSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcAlignmentParameterSegment::declaration() const { return *IFC4X3_RC3_IfcAlignmentParameterSegment_type; }
@@ -13424,7 +13424,7 @@ void Ifc4x3_rc3::IfcAlignmentVerticalSegment::setStartGradient(double v) { {IfcW
 double Ifc4x3_rc3::IfcAlignmentVerticalSegment::EndGradient() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcAlignmentVerticalSegment::setEndGradient(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAlignmentVerticalSegment::RadiusOfCurvature() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcAlignmentVerticalSegment::setRadiusOfCurvature(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcAlignmentVerticalSegment::setRadiusOfCurvature(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcAlignmentVerticalSegmentTypeEnum::Value Ifc4x3_rc3::IfcAlignmentVerticalSegment::PredefinedType() const {  return ::Ifc4x3_rc3::IfcAlignmentVerticalSegmentTypeEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc3::IfcAlignmentVerticalSegment::setPredefinedType(::Ifc4x3_rc3::IfcAlignmentVerticalSegmentTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcAlignmentVerticalSegmentTypeEnum::ToString(v)));data_->setArgument(8,attr);} }
 
@@ -13436,7 +13436,7 @@ Ifc4x3_rc3::IfcAlignmentVerticalSegment::IfcAlignmentVerticalSegment(boost::opti
 
 // Function implementations for IfcAnnotation
 boost::optional< ::Ifc4x3_rc3::IfcAnnotationTypeEnum::Value > Ifc4x3_rc3::IfcAnnotation::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcAnnotationTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc3::IfcAnnotation::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAnnotationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAnnotationTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcAnnotation::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAnnotationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAnnotationTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc3::IfcRelContainedInSpatialStructure::list::ptr Ifc4x3_rc3::IfcAnnotation::ContainedInStructure() const { return data_->getInverse(IFC4X3_RC3_IfcRelContainedInSpatialStructure_type, 4)->as<IfcRelContainedInSpatialStructure>(); }
 
@@ -13449,7 +13449,7 @@ Ifc4x3_rc3::IfcAnnotation::IfcAnnotation(std::string v1_GlobalId, ::Ifc4x3_rc3::
 ::Ifc4x3_rc3::IfcCurve* Ifc4x3_rc3::IfcAnnotationFillArea::OuterBoundary() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc3::IfcCurve>(true); }
 void Ifc4x3_rc3::IfcAnnotationFillArea::setOuterBoundary(::Ifc4x3_rc3::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcCurve >::ptr > Ifc4x3_rc3::IfcAnnotationFillArea::InnerBoundaries() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc3::IfcCurve >(); }
-void Ifc4x3_rc3::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcAnnotationFillArea::declaration() const { return *IFC4X3_RC3_IfcAnnotationFillArea_type; }
@@ -13475,25 +13475,25 @@ Ifc4x3_rc3::IfcApplication::IfcApplication(::Ifc4x3_rc3::IfcOrganization* v1_App
 
 // Function implementations for IfcAppliedValue
 boost::optional< std::string > Ifc4x3_rc3::IfcAppliedValue::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcAppliedValue::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc3::IfcAppliedValueSelect* Ifc4x3_rc3::IfcAppliedValue::AppliedValue() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc3::IfcAppliedValueSelect>(true); }
 void Ifc4x3_rc3::IfcAppliedValue::setAppliedValue(::Ifc4x3_rc3::IfcAppliedValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcMeasureWithUnit* Ifc4x3_rc3::IfcAppliedValue::UnitBasis() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcMeasureWithUnit>(true); }
 void Ifc4x3_rc3::IfcAppliedValue::setUnitBasis(::Ifc4x3_rc3::IfcMeasureWithUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcAppliedValue::ApplicableDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcAppliedValue::FixedUntilDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcAppliedValue::Category() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcAppliedValue::Condition() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcArithmeticOperatorEnum::Value > Ifc4x3_rc3::IfcAppliedValue::ArithmeticOperator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcArithmeticOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x3_rc3::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcArithmeticOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x3_rc3::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcArithmeticOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAppliedValue >::ptr > Ifc4x3_rc3::IfcAppliedValue::Components() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc3::IfcAppliedValue >(); }
-void Ifc4x3_rc3::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 
 ::Ifc4x3_rc3::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc3::IfcAppliedValue::HasExternalReference() const { return data_->getInverse(IFC4X3_RC3_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -13504,19 +13504,19 @@ Ifc4x3_rc3::IfcAppliedValue::IfcAppliedValue(boost::optional< std::string > v1_N
 
 // Function implementations for IfcApproval
 boost::optional< std::string > Ifc4x3_rc3::IfcApproval::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcApproval::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcApproval::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcApproval::TimeOfApproval() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcApproval::Status() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcApproval::Level() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcApproval::Qualifier() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc3::IfcActorSelect* Ifc4x3_rc3::IfcApproval::RequestingApproval() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc3::IfcActorSelect>(true); }
 void Ifc4x3_rc3::IfcApproval::setRequestingApproval(::Ifc4x3_rc3::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcActorSelect* Ifc4x3_rc3::IfcApproval::GivingApproval() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc3::IfcActorSelect>(true); }
@@ -13577,7 +13577,7 @@ Ifc4x3_rc3::IfcArbitraryProfileDefWithVoids::IfcArbitraryProfileDefWithVoids(::I
 
 // Function implementations for IfcAsset
 boost::optional< std::string > Ifc4x3_rc3::IfcAsset::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc3::IfcCostValue* Ifc4x3_rc3::IfcAsset::OriginalValue() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcCostValue>(true); }
 void Ifc4x3_rc3::IfcAsset::setOriginalValue(::Ifc4x3_rc3::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 ::Ifc4x3_rc3::IfcCostValue* Ifc4x3_rc3::IfcAsset::CurrentValue() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc3::IfcCostValue>(true); }
@@ -13591,7 +13591,7 @@ void Ifc4x3_rc3::IfcAsset::setUser(::Ifc4x3_rc3::IfcActorSelect* v) { {IfcWrite:
 ::Ifc4x3_rc3::IfcPerson* Ifc4x3_rc3::IfcAsset::ResponsiblePerson() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc3::IfcPerson>(true); }
 void Ifc4x3_rc3::IfcAsset::setResponsiblePerson(::Ifc4x3_rc3::IfcPerson* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcAsset::IncorporationDate() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x3_rc3::IfcCostValue* Ifc4x3_rc3::IfcAsset::DepreciatedValue() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x3_rc3::IfcCostValue>(true); }
 void Ifc4x3_rc3::IfcAsset::setDepreciatedValue(::Ifc4x3_rc3::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -13611,21 +13611,21 @@ void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setWebThickness(double v) { {Ifc
 double Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::BottomFlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setBottomFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::BottomFlangeFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 double Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::TopFlangeWidth() const {  double v = *data_->getArgument(8); return v; }
 void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setTopFlangeWidth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::TopFlangeThickness() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::TopFlangeFilletRadius() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::BottomFlangeEdgeRadius() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::BottomFlangeSlope() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::TopFlangeEdgeRadius() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::TopFlangeSlope() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::declaration() const { return *IFC4X3_RC3_IfcAsymmetricIShapeProfileDef_type; }
@@ -13635,7 +13635,7 @@ Ifc4x3_rc3::IfcAsymmetricIShapeProfileDef::IfcAsymmetricIShapeProfileDef(::Ifc4x
 
 // Function implementations for IfcAudioVisualAppliance
 boost::optional< ::Ifc4x3_rc3::IfcAudioVisualApplianceTypeEnum::Value > Ifc4x3_rc3::IfcAudioVisualAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcAudioVisualApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAudioVisualApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAudioVisualApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcAudioVisualAppliance::declaration() const { return *IFC4X3_RC3_IfcAudioVisualAppliance_type; }
@@ -13771,7 +13771,7 @@ Ifc4x3_rc3::IfcBSplineSurfaceWithKnots::IfcBSplineSurfaceWithKnots(int v1_UDegre
 
 // Function implementations for IfcBeam
 boost::optional< ::Ifc4x3_rc3::IfcBeamTypeEnum::Value > Ifc4x3_rc3::IfcBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBeam::declaration() const { return *IFC4X3_RC3_IfcBeam_type; }
@@ -13799,7 +13799,7 @@ Ifc4x3_rc3::IfcBeamType::IfcBeamType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcBearing
 boost::optional< ::Ifc4x3_rc3::IfcBearingTypeEnum::Value > Ifc4x3_rc3::IfcBearing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcBearingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcBearing::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBearingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBearingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcBearing::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBearingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBearingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBearing::declaration() const { return *IFC4X3_RC3_IfcBearing_type; }
@@ -13845,7 +13845,7 @@ Ifc4x3_rc3::IfcBlock::IfcBlock(::Ifc4x3_rc3::IfcAxis2Placement3D* v1_Position, d
 
 // Function implementations for IfcBoiler
 boost::optional< ::Ifc4x3_rc3::IfcBoilerTypeEnum::Value > Ifc4x3_rc3::IfcBoiler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcBoilerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBoilerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBoilerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBoiler::declaration() const { return *IFC4X3_RC3_IfcBoiler_type; }
@@ -13895,7 +13895,7 @@ Ifc4x3_rc3::IfcBorehole::IfcBorehole(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcBoundaryCondition
 boost::optional< std::string > Ifc4x3_rc3::IfcBoundaryCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBoundaryCondition::declaration() const { return *IFC4X3_RC3_IfcBoundaryCondition_type; }
@@ -14019,7 +14019,7 @@ Ifc4x3_rc3::IfcBoxedHalfSpace::IfcBoxedHalfSpace(::Ifc4x3_rc3::IfcSurface* v1_Ba
 
 // Function implementations for IfcBridge
 boost::optional< ::Ifc4x3_rc3::IfcBridgeTypeEnum::Value > Ifc4x3_rc3::IfcBridge::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcBridgeTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcBridge::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBridgeTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBridgeTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcBridge::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBridgeTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBridgeTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBridge::declaration() const { return *IFC4X3_RC3_IfcBridge_type; }
@@ -14029,9 +14029,9 @@ Ifc4x3_rc3::IfcBridge::IfcBridge(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwner
 
 // Function implementations for IfcBuilding
 boost::optional< double > Ifc4x3_rc3::IfcBuilding::ElevationOfRefHeight() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcBuilding::ElevationOfTerrain() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc3::IfcPostalAddress* Ifc4x3_rc3::IfcBuilding::BuildingAddress() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc3::IfcPostalAddress>(true); }
 void Ifc4x3_rc3::IfcBuilding::setBuildingAddress(::Ifc4x3_rc3::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 
@@ -14043,7 +14043,7 @@ Ifc4x3_rc3::IfcBuilding::IfcBuilding(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcBuildingElementPart
 boost::optional< ::Ifc4x3_rc3::IfcBuildingElementPartTypeEnum::Value > Ifc4x3_rc3::IfcBuildingElementPart::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcBuildingElementPartTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBuildingElementPartTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBuildingElementPartTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBuildingElementPart::declaration() const { return *IFC4X3_RC3_IfcBuildingElementPart_type; }
@@ -14063,7 +14063,7 @@ Ifc4x3_rc3::IfcBuildingElementPartType::IfcBuildingElementPartType(std::string v
 
 // Function implementations for IfcBuildingElementProxy
 boost::optional< ::Ifc4x3_rc3::IfcBuildingElementProxyTypeEnum::Value > Ifc4x3_rc3::IfcBuildingElementProxy::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcBuildingElementProxyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBuildingElementProxyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBuildingElementProxyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBuildingElementProxy::declaration() const { return *IFC4X3_RC3_IfcBuildingElementProxy_type; }
@@ -14083,7 +14083,7 @@ Ifc4x3_rc3::IfcBuildingElementProxyType::IfcBuildingElementProxyType(std::string
 
 // Function implementations for IfcBuildingStorey
 boost::optional< double > Ifc4x3_rc3::IfcBuildingStorey::Elevation() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBuildingStorey::declaration() const { return *IFC4X3_RC3_IfcBuildingStorey_type; }
@@ -14093,9 +14093,9 @@ Ifc4x3_rc3::IfcBuildingStorey::IfcBuildingStorey(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcBuildingSystem
 boost::optional< ::Ifc4x3_rc3::IfcBuildingSystemTypeEnum::Value > Ifc4x3_rc3::IfcBuildingSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcBuildingSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc3::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBuildingSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBuildingSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcBuildingSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBuildingSystem::declaration() const { return *IFC4X3_RC3_IfcBuildingSystem_type; }
@@ -14121,9 +14121,9 @@ Ifc4x3_rc3::IfcBuiltElementType::IfcBuiltElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcBuiltSystem
 boost::optional< ::Ifc4x3_rc3::IfcBuiltSystemTypeEnum::Value > Ifc4x3_rc3::IfcBuiltSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcBuiltSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc3::IfcBuiltSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBuiltSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBuiltSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcBuiltSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBuiltSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBuiltSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcBuiltSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcBuiltSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcBuiltSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBuiltSystem::declaration() const { return *IFC4X3_RC3_IfcBuiltSystem_type; }
@@ -14133,7 +14133,7 @@ Ifc4x3_rc3::IfcBuiltSystem::IfcBuiltSystem(std::string v1_GlobalId, ::Ifc4x3_rc3
 
 // Function implementations for IfcBurner
 boost::optional< ::Ifc4x3_rc3::IfcBurnerTypeEnum::Value > Ifc4x3_rc3::IfcBurner::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcBurnerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBurnerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcBurnerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcBurner::declaration() const { return *IFC4X3_RC3_IfcBurner_type; }
@@ -14161,7 +14161,7 @@ void Ifc4x3_rc3::IfcCShapeProfileDef::setWallThickness(double v) { {IfcWrite::If
 double Ifc4x3_rc3::IfcCShapeProfileDef::Girth() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcCShapeProfileDef::setGirth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcCShapeProfileDef::InternalFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCShapeProfileDef::declaration() const { return *IFC4X3_RC3_IfcCShapeProfileDef_type; }
@@ -14171,7 +14171,7 @@ Ifc4x3_rc3::IfcCShapeProfileDef::IfcCShapeProfileDef(::Ifc4x3_rc3::IfcProfileTyp
 
 // Function implementations for IfcCableCarrierFitting
 boost::optional< ::Ifc4x3_rc3::IfcCableCarrierFittingTypeEnum::Value > Ifc4x3_rc3::IfcCableCarrierFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCableCarrierFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCableCarrierFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCableCarrierFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCableCarrierFitting::declaration() const { return *IFC4X3_RC3_IfcCableCarrierFitting_type; }
@@ -14191,7 +14191,7 @@ Ifc4x3_rc3::IfcCableCarrierFittingType::IfcCableCarrierFittingType(std::string v
 
 // Function implementations for IfcCableCarrierSegment
 boost::optional< ::Ifc4x3_rc3::IfcCableCarrierSegmentTypeEnum::Value > Ifc4x3_rc3::IfcCableCarrierSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCableCarrierSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCableCarrierSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCableCarrierSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCableCarrierSegment::declaration() const { return *IFC4X3_RC3_IfcCableCarrierSegment_type; }
@@ -14211,7 +14211,7 @@ Ifc4x3_rc3::IfcCableCarrierSegmentType::IfcCableCarrierSegmentType(std::string v
 
 // Function implementations for IfcCableFitting
 boost::optional< ::Ifc4x3_rc3::IfcCableFittingTypeEnum::Value > Ifc4x3_rc3::IfcCableFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCableFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCableFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCableFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCableFitting::declaration() const { return *IFC4X3_RC3_IfcCableFitting_type; }
@@ -14231,7 +14231,7 @@ Ifc4x3_rc3::IfcCableFittingType::IfcCableFittingType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcCableSegment
 boost::optional< ::Ifc4x3_rc3::IfcCableSegmentTypeEnum::Value > Ifc4x3_rc3::IfcCableSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCableSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCableSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCableSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCableSegment::declaration() const { return *IFC4X3_RC3_IfcCableSegment_type; }
@@ -14251,7 +14251,7 @@ Ifc4x3_rc3::IfcCableSegmentType::IfcCableSegmentType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcCaissonFoundation
 boost::optional< ::Ifc4x3_rc3::IfcCaissonFoundationTypeEnum::Value > Ifc4x3_rc3::IfcCaissonFoundation::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCaissonFoundationTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCaissonFoundation::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCaissonFoundationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCaissonFoundationTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCaissonFoundation::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCaissonFoundationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCaissonFoundationTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCaissonFoundation::declaration() const { return *IFC4X3_RC3_IfcCaissonFoundation_type; }
@@ -14291,7 +14291,7 @@ Ifc4x3_rc3::IfcCartesianPointList::IfcCartesianPointList() : IfcGeometricReprese
 std::vector< std::vector< double > > Ifc4x3_rc3::IfcCartesianPointList2D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc3::IfcCartesianPointList2D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcCartesianPointList2D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCartesianPointList2D::declaration() const { return *IFC4X3_RC3_IfcCartesianPointList2D_type; }
@@ -14303,7 +14303,7 @@ Ifc4x3_rc3::IfcCartesianPointList2D::IfcCartesianPointList2D(std::vector< std::v
 std::vector< std::vector< double > > Ifc4x3_rc3::IfcCartesianPointList3D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc3::IfcCartesianPointList3D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcCartesianPointList3D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCartesianPointList3D::declaration() const { return *IFC4X3_RC3_IfcCartesianPointList3D_type; }
@@ -14319,7 +14319,7 @@ void Ifc4x3_rc3::IfcCartesianTransformationOperator::setAxis2(::Ifc4x3_rc3::IfcD
 ::Ifc4x3_rc3::IfcCartesianPoint* Ifc4x3_rc3::IfcCartesianTransformationOperator::LocalOrigin() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc3::IfcCartesianPoint>(true); }
 void Ifc4x3_rc3::IfcCartesianTransformationOperator::setLocalOrigin(::Ifc4x3_rc3::IfcCartesianPoint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcCartesianTransformationOperator::Scale() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCartesianTransformationOperator::declaration() const { return *IFC4X3_RC3_IfcCartesianTransformationOperator_type; }
@@ -14337,7 +14337,7 @@ Ifc4x3_rc3::IfcCartesianTransformationOperator2D::IfcCartesianTransformationOper
 
 // Function implementations for IfcCartesianTransformationOperator2DnonUniform
 boost::optional< double > Ifc4x3_rc3::IfcCartesianTransformationOperator2DnonUniform::Scale2() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCartesianTransformationOperator2DnonUniform::declaration() const { return *IFC4X3_RC3_IfcCartesianTransformationOperator2DnonUniform_type; }
@@ -14357,9 +14357,9 @@ Ifc4x3_rc3::IfcCartesianTransformationOperator3D::IfcCartesianTransformationOper
 
 // Function implementations for IfcCartesianTransformationOperator3DnonUniform
 boost::optional< double > Ifc4x3_rc3::IfcCartesianTransformationOperator3DnonUniform::Scale2() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcCartesianTransformationOperator3DnonUniform::Scale3() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCartesianTransformationOperator3DnonUniform::declaration() const { return *IFC4X3_RC3_IfcCartesianTransformationOperator3DnonUniform_type; }
@@ -14379,7 +14379,7 @@ Ifc4x3_rc3::IfcCenterLineProfileDef::IfcCenterLineProfileDef(::Ifc4x3_rc3::IfcPr
 
 // Function implementations for IfcChiller
 boost::optional< ::Ifc4x3_rc3::IfcChillerTypeEnum::Value > Ifc4x3_rc3::IfcChiller::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcChillerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcChillerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcChillerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcChiller::declaration() const { return *IFC4X3_RC3_IfcChiller_type; }
@@ -14399,7 +14399,7 @@ Ifc4x3_rc3::IfcChillerType::IfcChillerType(std::string v1_GlobalId, ::Ifc4x3_rc3
 
 // Function implementations for IfcChimney
 boost::optional< ::Ifc4x3_rc3::IfcChimneyTypeEnum::Value > Ifc4x3_rc3::IfcChimney::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcChimneyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcChimneyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcChimneyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcChimney::declaration() const { return *IFC4X3_RC3_IfcChimney_type; }
@@ -14465,19 +14465,19 @@ Ifc4x3_rc3::IfcCivilElementType::IfcCivilElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcClassification
 boost::optional< std::string > Ifc4x3_rc3::IfcClassification::Source() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcClassification::Edition() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcClassification::EditionDate() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::string Ifc4x3_rc3::IfcClassification::Name() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcClassification::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcClassification::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcClassification::Location() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcClassification::ReferenceTokens() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc3::IfcRelAssociatesClassification::list::ptr Ifc4x3_rc3::IfcClassification::ClassificationForObjects() const { return data_->getInverse(IFC4X3_RC3_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x3_rc3::IfcClassificationReference::list::ptr Ifc4x3_rc3::IfcClassification::HasReferences() const { return data_->getInverse(IFC4X3_RC3_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -14491,9 +14491,9 @@ Ifc4x3_rc3::IfcClassification::IfcClassification(boost::optional< std::string >
 ::Ifc4x3_rc3::IfcClassificationReferenceSelect* Ifc4x3_rc3::IfcClassificationReference::ReferencedSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcClassificationReferenceSelect>(true); }
 void Ifc4x3_rc3::IfcClassificationReference::setReferencedSource(::Ifc4x3_rc3::IfcClassificationReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcClassificationReference::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcClassificationReference::Sort() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc3::IfcRelAssociatesClassification::list::ptr Ifc4x3_rc3::IfcClassificationReference::ClassificationRefForObjects() const { return data_->getInverse(IFC4X3_RC3_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x3_rc3::IfcClassificationReference::list::ptr Ifc4x3_rc3::IfcClassificationReference::HasReferences() const { return data_->getInverse(IFC4X3_RC3_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -14523,7 +14523,7 @@ Ifc4x3_rc3::IfcClothoid::IfcClothoid(::Ifc4x3_rc3::IfcAxis2Placement* v1_Positio
 
 // Function implementations for IfcCoil
 boost::optional< ::Ifc4x3_rc3::IfcCoilTypeEnum::Value > Ifc4x3_rc3::IfcCoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCoil::declaration() const { return *IFC4X3_RC3_IfcCoil_type; }
@@ -14567,7 +14567,7 @@ Ifc4x3_rc3::IfcColourRgbList::IfcColourRgbList(std::vector< std::vector< double
 
 // Function implementations for IfcColourSpecification
 boost::optional< std::string > Ifc4x3_rc3::IfcColourSpecification::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcColourSpecification::declaration() const { return *IFC4X3_RC3_IfcColourSpecification_type; }
@@ -14577,7 +14577,7 @@ Ifc4x3_rc3::IfcColourSpecification::IfcColourSpecification(boost::optional< std:
 
 // Function implementations for IfcColumn
 boost::optional< ::Ifc4x3_rc3::IfcColumnTypeEnum::Value > Ifc4x3_rc3::IfcColumn::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcColumnTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcColumnTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcColumnTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcColumn::declaration() const { return *IFC4X3_RC3_IfcColumn_type; }
@@ -14605,7 +14605,7 @@ Ifc4x3_rc3::IfcColumnType::IfcColumnType(std::string v1_GlobalId, ::Ifc4x3_rc3::
 
 // Function implementations for IfcCommunicationsAppliance
 boost::optional< ::Ifc4x3_rc3::IfcCommunicationsApplianceTypeEnum::Value > Ifc4x3_rc3::IfcCommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCommunicationsAppliance::declaration() const { return *IFC4X3_RC3_IfcCommunicationsAppliance_type; }
@@ -14637,11 +14637,11 @@ Ifc4x3_rc3::IfcComplexProperty::IfcComplexProperty(std::string v1_Name, boost::o
 
 // Function implementations for IfcComplexPropertyTemplate
 boost::optional< std::string > Ifc4x3_rc3::IfcComplexPropertyTemplate::UsageName() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcComplexPropertyTemplateTypeEnum::Value > Ifc4x3_rc3::IfcComplexPropertyTemplate::TemplateType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcComplexPropertyTemplateTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc3::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc3::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc3::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPropertyTemplate >::ptr > Ifc4x3_rc3::IfcComplexPropertyTemplate::HasPropertyTemplates() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc3::IfcPropertyTemplate >(); }
-void Ifc4x3_rc3::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcComplexPropertyTemplate::declaration() const { return *IFC4X3_RC3_IfcComplexPropertyTemplate_type; }
@@ -14685,7 +14685,7 @@ Ifc4x3_rc3::IfcCompositeCurveSegment::IfcCompositeCurveSegment(::Ifc4x3_rc3::Ifc
 aggregate_of< ::Ifc4x3_rc3::IfcProfileDef >::ptr Ifc4x3_rc3::IfcCompositeProfileDef::Profiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc3::IfcProfileDef >(); }
 void Ifc4x3_rc3::IfcCompositeProfileDef::setProfiles(aggregate_of< ::Ifc4x3_rc3::IfcProfileDef >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcCompositeProfileDef::Label() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCompositeProfileDef::declaration() const { return *IFC4X3_RC3_IfcCompositeProfileDef_type; }
@@ -14695,7 +14695,7 @@ Ifc4x3_rc3::IfcCompositeProfileDef::IfcCompositeProfileDef(::Ifc4x3_rc3::IfcProf
 
 // Function implementations for IfcCompressor
 boost::optional< ::Ifc4x3_rc3::IfcCompressorTypeEnum::Value > Ifc4x3_rc3::IfcCompressor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCompressorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCompressorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCompressorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCompressor::declaration() const { return *IFC4X3_RC3_IfcCompressor_type; }
@@ -14715,7 +14715,7 @@ Ifc4x3_rc3::IfcCompressorType::IfcCompressorType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCondenser
 boost::optional< ::Ifc4x3_rc3::IfcCondenserTypeEnum::Value > Ifc4x3_rc3::IfcCondenser::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCondenserTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCondenserTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCondenserTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCondenser::declaration() const { return *IFC4X3_RC3_IfcCondenser_type; }
@@ -14775,11 +14775,11 @@ Ifc4x3_rc3::IfcConnectionGeometry::IfcConnectionGeometry() : IfcUtil::IfcBaseEnt
 
 // Function implementations for IfcConnectionPointEccentricity
 boost::optional< double > Ifc4x3_rc3::IfcConnectionPointEccentricity::EccentricityInX() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcConnectionPointEccentricity::EccentricityInY() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcConnectionPointEccentricity::EccentricityInZ() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcConnectionPointEccentricity::declaration() const { return *IFC4X3_RC3_IfcConnectionPointEccentricity_type; }
@@ -14827,17 +14827,17 @@ Ifc4x3_rc3::IfcConnectionVolumeGeometry::IfcConnectionVolumeGeometry(::Ifc4x3_rc
 std::string Ifc4x3_rc3::IfcConstraint::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc3::IfcConstraint::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcConstraint::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc3::IfcConstraintEnum::Value Ifc4x3_rc3::IfcConstraint::ConstraintGrade() const {  return ::Ifc4x3_rc3::IfcConstraintEnum::FromString(*data_->getArgument(2)); }
 void Ifc4x3_rc3::IfcConstraint::setConstraintGrade(::Ifc4x3_rc3::IfcConstraintEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcConstraintEnum::ToString(v)));data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcConstraint::ConstraintSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc3::IfcActorSelect* Ifc4x3_rc3::IfcConstraint::CreatingActor() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc3::IfcActorSelect>(true); }
 void Ifc4x3_rc3::IfcConstraint::setCreatingActor(::Ifc4x3_rc3::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcConstraint::CreationTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcConstraint::UserDefinedGrade() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc3::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc3::IfcConstraint::HasExternalReferences() const { return data_->getInverse(IFC4X3_RC3_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc3::IfcResourceConstraintRelationship::list::ptr Ifc4x3_rc3::IfcConstraint::PropertiesForConstraint() const { return data_->getInverse(IFC4X3_RC3_IfcResourceConstraintRelationship_type, 2)->as<IfcResourceConstraintRelationship>(); }
@@ -14849,7 +14849,7 @@ Ifc4x3_rc3::IfcConstraint::IfcConstraint(std::string v1_Name, boost::optional< s
 
 // Function implementations for IfcConstructionEquipmentResource
 boost::optional< ::Ifc4x3_rc3::IfcConstructionEquipmentResourceTypeEnum::Value > Ifc4x3_rc3::IfcConstructionEquipmentResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcConstructionEquipmentResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcConstructionEquipmentResource::declaration() const { return *IFC4X3_RC3_IfcConstructionEquipmentResource_type; }
@@ -14869,7 +14869,7 @@ Ifc4x3_rc3::IfcConstructionEquipmentResourceType::IfcConstructionEquipmentResour
 
 // Function implementations for IfcConstructionMaterialResource
 boost::optional< ::Ifc4x3_rc3::IfcConstructionMaterialResourceTypeEnum::Value > Ifc4x3_rc3::IfcConstructionMaterialResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcConstructionMaterialResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcConstructionMaterialResource::declaration() const { return *IFC4X3_RC3_IfcConstructionMaterialResource_type; }
@@ -14889,7 +14889,7 @@ Ifc4x3_rc3::IfcConstructionMaterialResourceType::IfcConstructionMaterialResource
 
 // Function implementations for IfcConstructionProductResource
 boost::optional< ::Ifc4x3_rc3::IfcConstructionProductResourceTypeEnum::Value > Ifc4x3_rc3::IfcConstructionProductResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcConstructionProductResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcConstructionProductResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcConstructionProductResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcConstructionProductResource::declaration() const { return *IFC4X3_RC3_IfcConstructionProductResource_type; }
@@ -14911,7 +14911,7 @@ Ifc4x3_rc3::IfcConstructionProductResourceType::IfcConstructionProductResourceTy
 ::Ifc4x3_rc3::IfcResourceTime* Ifc4x3_rc3::IfcConstructionResource::Usage() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc3::IfcResourceTime>(true); }
 void Ifc4x3_rc3::IfcConstructionResource::setUsage(::Ifc4x3_rc3::IfcResourceTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAppliedValue >::ptr > Ifc4x3_rc3::IfcConstructionResource::BaseCosts() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc3::IfcAppliedValue >(); }
-void Ifc4x3_rc3::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc3::IfcPhysicalQuantity* Ifc4x3_rc3::IfcConstructionResource::BaseQuantity() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc3::IfcPhysicalQuantity>(true); }
 void Ifc4x3_rc3::IfcConstructionResource::setBaseQuantity(::Ifc4x3_rc3::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -14923,7 +14923,7 @@ Ifc4x3_rc3::IfcConstructionResource::IfcConstructionResource(std::string v1_Glob
 
 // Function implementations for IfcConstructionResourceType
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAppliedValue >::ptr > Ifc4x3_rc3::IfcConstructionResourceType::BaseCosts() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc3::IfcAppliedValue >(); }
-void Ifc4x3_rc3::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 ::Ifc4x3_rc3::IfcPhysicalQuantity* Ifc4x3_rc3::IfcConstructionResourceType::BaseQuantity() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc3::IfcPhysicalQuantity>(true); }
 void Ifc4x3_rc3::IfcConstructionResourceType::setBaseQuantity(::Ifc4x3_rc3::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -14935,13 +14935,13 @@ Ifc4x3_rc3::IfcConstructionResourceType::IfcConstructionResourceType(std::string
 
 // Function implementations for IfcContext
 boost::optional< std::string > Ifc4x3_rc3::IfcContext::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcContext::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcContext::Phase() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcRepresentationContext >::ptr > Ifc4x3_rc3::IfcContext::RepresentationContexts() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc3::IfcRepresentationContext >(); }
-void Ifc4x3_rc3::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcUnitAssignment* Ifc4x3_rc3::IfcContext::UnitsInContext() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc3::IfcUnitAssignment>(true); }
 void Ifc4x3_rc3::IfcContext::setUnitsInContext(::Ifc4x3_rc3::IfcUnitAssignment* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -14966,7 +14966,7 @@ Ifc4x3_rc3::IfcContextDependentUnit::IfcContextDependentUnit(::Ifc4x3_rc3::IfcDi
 
 // Function implementations for IfcControl
 boost::optional< std::string > Ifc4x3_rc3::IfcControl::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc3::IfcRelAssignsToControl::list::ptr Ifc4x3_rc3::IfcControl::Controls() const { return data_->getInverse(IFC4X3_RC3_IfcRelAssignsToControl_type, 6)->as<IfcRelAssignsToControl>(); }
 
@@ -14977,7 +14977,7 @@ Ifc4x3_rc3::IfcControl::IfcControl(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwn
 
 // Function implementations for IfcController
 boost::optional< ::Ifc4x3_rc3::IfcControllerTypeEnum::Value > Ifc4x3_rc3::IfcController::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcControllerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcController::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcControllerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcController::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcControllerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcController::declaration() const { return *IFC4X3_RC3_IfcController_type; }
@@ -15020,7 +15020,7 @@ Ifc4x3_rc3::IfcConversionBasedUnitWithOffset::IfcConversionBasedUnitWithOffset(:
 
 // Function implementations for IfcConveyorSegment
 boost::optional< ::Ifc4x3_rc3::IfcConveyorSegmentTypeEnum::Value > Ifc4x3_rc3::IfcConveyorSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcConveyorSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcConveyorSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcConveyorSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcConveyorSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcConveyorSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcConveyorSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcConveyorSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcConveyorSegment::declaration() const { return *IFC4X3_RC3_IfcConveyorSegment_type; }
@@ -15040,7 +15040,7 @@ Ifc4x3_rc3::IfcConveyorSegmentType::IfcConveyorSegmentType(std::string v1_Global
 
 // Function implementations for IfcCooledBeam
 boost::optional< ::Ifc4x3_rc3::IfcCooledBeamTypeEnum::Value > Ifc4x3_rc3::IfcCooledBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCooledBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCooledBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCooledBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCooledBeam::declaration() const { return *IFC4X3_RC3_IfcCooledBeam_type; }
@@ -15060,7 +15060,7 @@ Ifc4x3_rc3::IfcCooledBeamType::IfcCooledBeamType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCoolingTower
 boost::optional< ::Ifc4x3_rc3::IfcCoolingTowerTypeEnum::Value > Ifc4x3_rc3::IfcCoolingTower::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCoolingTowerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCoolingTowerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCoolingTowerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCoolingTower::declaration() const { return *IFC4X3_RC3_IfcCoolingTower_type; }
@@ -15094,11 +15094,11 @@ Ifc4x3_rc3::IfcCoordinateOperation::IfcCoordinateOperation(::Ifc4x3_rc3::IfcCoor
 std::string Ifc4x3_rc3::IfcCoordinateReferenceSystem::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc3::IfcCoordinateReferenceSystem::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcCoordinateReferenceSystem::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcCoordinateReferenceSystem::GeodeticDatum() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcCoordinateReferenceSystem::VerticalDatum() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 ::Ifc4x3_rc3::IfcCoordinateOperation::list::ptr Ifc4x3_rc3::IfcCoordinateReferenceSystem::HasCoordinateOperation() const { return data_->getInverse(IFC4X3_RC3_IfcCoordinateOperation_type, 0)->as<IfcCoordinateOperation>(); }
 
@@ -15121,11 +15121,11 @@ Ifc4x3_rc3::IfcCosine::IfcCosine(::Ifc4x3_rc3::IfcAxis2Placement* v1_Position, d
 
 // Function implementations for IfcCostItem
 boost::optional< ::Ifc4x3_rc3::IfcCostItemTypeEnum::Value > Ifc4x3_rc3::IfcCostItem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCostItemTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc3::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCostItemTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCostItemTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcCostValue >::ptr > Ifc4x3_rc3::IfcCostItem::CostValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc3::IfcCostValue >(); }
-void Ifc4x3_rc3::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPhysicalQuantity >::ptr > Ifc4x3_rc3::IfcCostItem::CostQuantities() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc3::IfcPhysicalQuantity >(); }
-void Ifc4x3_rc3::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCostItem::declaration() const { return *IFC4X3_RC3_IfcCostItem_type; }
@@ -15135,13 +15135,13 @@ Ifc4x3_rc3::IfcCostItem::IfcCostItem(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcCostSchedule
 boost::optional< ::Ifc4x3_rc3::IfcCostScheduleTypeEnum::Value > Ifc4x3_rc3::IfcCostSchedule::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCostScheduleTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc3::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCostScheduleTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCostScheduleTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcCostSchedule::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcCostSchedule::SubmittedOn() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcCostSchedule::UpdateDate() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCostSchedule::declaration() const { return *IFC4X3_RC3_IfcCostSchedule_type; }
@@ -15159,7 +15159,7 @@ Ifc4x3_rc3::IfcCostValue::IfcCostValue(boost::optional< std::string > v1_Name, b
 
 // Function implementations for IfcCourse
 boost::optional< ::Ifc4x3_rc3::IfcCourseTypeEnum::Value > Ifc4x3_rc3::IfcCourse::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCourseTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCourse::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCourseTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCourseTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCourse::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCourseTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCourseTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCourse::declaration() const { return *IFC4X3_RC3_IfcCourse_type; }
@@ -15179,7 +15179,7 @@ Ifc4x3_rc3::IfcCourseType::IfcCourseType(std::string v1_GlobalId, ::Ifc4x3_rc3::
 
 // Function implementations for IfcCovering
 boost::optional< ::Ifc4x3_rc3::IfcCoveringTypeEnum::Value > Ifc4x3_rc3::IfcCovering::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCoveringTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCoveringTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCoveringTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc3::IfcRelCoversSpaces::list::ptr Ifc4x3_rc3::IfcCovering::CoversSpaces() const { return data_->getInverse(IFC4X3_RC3_IfcRelCoversSpaces_type, 5)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x3_rc3::IfcRelCoversBldgElements::list::ptr Ifc4x3_rc3::IfcCovering::CoversElements() const { return data_->getInverse(IFC4X3_RC3_IfcRelCoversBldgElements_type, 5)->as<IfcRelCoversBldgElements>(); }
@@ -15201,7 +15201,7 @@ Ifc4x3_rc3::IfcCoveringType::IfcCoveringType(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcCrewResource
 boost::optional< ::Ifc4x3_rc3::IfcCrewResourceTypeEnum::Value > Ifc4x3_rc3::IfcCrewResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCrewResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCrewResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCrewResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCrewResource::declaration() const { return *IFC4X3_RC3_IfcCrewResource_type; }
@@ -15247,7 +15247,7 @@ void Ifc4x3_rc3::IfcCurrencyRelationship::setRelatedMonetaryUnit(::Ifc4x3_rc3::I
 double Ifc4x3_rc3::IfcCurrencyRelationship::ExchangeRate() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc3::IfcCurrencyRelationship::setExchangeRate(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcCurrencyRelationship::RateDateTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc3::IfcLibraryInformation* Ifc4x3_rc3::IfcCurrencyRelationship::RateSource() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcLibraryInformation>(true); }
 void Ifc4x3_rc3::IfcCurrencyRelationship::setRateSource(::Ifc4x3_rc3::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -15259,7 +15259,7 @@ Ifc4x3_rc3::IfcCurrencyRelationship::IfcCurrencyRelationship(boost::optional< st
 
 // Function implementations for IfcCurtainWall
 boost::optional< ::Ifc4x3_rc3::IfcCurtainWallTypeEnum::Value > Ifc4x3_rc3::IfcCurtainWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCurtainWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCurtainWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCurtainWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCurtainWall::declaration() const { return *IFC4X3_RC3_IfcCurtainWall_type; }
@@ -15337,7 +15337,7 @@ void Ifc4x3_rc3::IfcCurveStyle::setCurveWidth(::Ifc4x3_rc3::IfcSizeSelect* v) {
 ::Ifc4x3_rc3::IfcColour* Ifc4x3_rc3::IfcCurveStyle::CurveColour() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcColour>(true); }
 void Ifc4x3_rc3::IfcCurveStyle::setCurveColour(::Ifc4x3_rc3::IfcColour* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x3_rc3::IfcCurveStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcCurveStyle::declaration() const { return *IFC4X3_RC3_IfcCurveStyle_type; }
@@ -15347,7 +15347,7 @@ Ifc4x3_rc3::IfcCurveStyle::IfcCurveStyle(boost::optional< std::string > v1_Name,
 
 // Function implementations for IfcCurveStyleFont
 boost::optional< std::string > Ifc4x3_rc3::IfcCurveStyleFont::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc4x3_rc3::IfcCurveStyleFontPattern >::ptr Ifc4x3_rc3::IfcCurveStyleFont::PatternList() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc3::IfcCurveStyleFontPattern >(); }
 void Ifc4x3_rc3::IfcCurveStyleFont::setPatternList(aggregate_of< ::Ifc4x3_rc3::IfcCurveStyleFontPattern >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -15359,7 +15359,7 @@ Ifc4x3_rc3::IfcCurveStyleFont::IfcCurveStyleFont(boost::optional< std::string >
 
 // Function implementations for IfcCurveStyleFontAndScaling
 boost::optional< std::string > Ifc4x3_rc3::IfcCurveStyleFontAndScaling::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc3::IfcCurveStyleFontSelect* Ifc4x3_rc3::IfcCurveStyleFontAndScaling::CurveFont() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc3::IfcCurveStyleFontSelect>(true); }
 void Ifc4x3_rc3::IfcCurveStyleFontAndScaling::setCurveFont(::Ifc4x3_rc3::IfcCurveStyleFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 double Ifc4x3_rc3::IfcCurveStyleFontAndScaling::CurveFontScaling() const {  double v = *data_->getArgument(2); return v; }
@@ -15395,7 +15395,7 @@ Ifc4x3_rc3::IfcCylindricalSurface::IfcCylindricalSurface(::Ifc4x3_rc3::IfcAxis2P
 
 // Function implementations for IfcDamper
 boost::optional< ::Ifc4x3_rc3::IfcDamperTypeEnum::Value > Ifc4x3_rc3::IfcDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDamper::declaration() const { return *IFC4X3_RC3_IfcDamper_type; }
@@ -15435,7 +15435,7 @@ void Ifc4x3_rc3::IfcDerivedProfileDef::setParentProfile(::Ifc4x3_rc3::IfcProfile
 ::Ifc4x3_rc3::IfcCartesianTransformationOperator2D* Ifc4x3_rc3::IfcDerivedProfileDef::Operator() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x3_rc3::IfcDerivedProfileDef::setOperator(::Ifc4x3_rc3::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDerivedProfileDef::Label() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDerivedProfileDef::declaration() const { return *IFC4X3_RC3_IfcDerivedProfileDef_type; }
@@ -15449,7 +15449,7 @@ void Ifc4x3_rc3::IfcDerivedUnit::setElements(aggregate_of< ::Ifc4x3_rc3::IfcDeri
 ::Ifc4x3_rc3::IfcDerivedUnitEnum::Value Ifc4x3_rc3::IfcDerivedUnit::UnitType() const {  return ::Ifc4x3_rc3::IfcDerivedUnitEnum::FromString(*data_->getArgument(1)); }
 void Ifc4x3_rc3::IfcDerivedUnit::setUnitType(::Ifc4x3_rc3::IfcDerivedUnitEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcDerivedUnitEnum::ToString(v)));data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDerivedUnit::UserDefinedType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDerivedUnit::declaration() const { return *IFC4X3_RC3_IfcDerivedUnit_type; }
@@ -15539,7 +15539,7 @@ Ifc4x3_rc3::IfcDirectrixDistanceSweptAreaSolid::IfcDirectrixDistanceSweptAreaSol
 
 // Function implementations for IfcDiscreteAccessory
 boost::optional< ::Ifc4x3_rc3::IfcDiscreteAccessoryTypeEnum::Value > Ifc4x3_rc3::IfcDiscreteAccessory::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDiscreteAccessoryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDiscreteAccessoryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDiscreteAccessoryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDiscreteAccessory::declaration() const { return *IFC4X3_RC3_IfcDiscreteAccessory_type; }
@@ -15559,7 +15559,7 @@ Ifc4x3_rc3::IfcDiscreteAccessoryType::IfcDiscreteAccessoryType(std::string v1_Gl
 
 // Function implementations for IfcDistributionBoard
 boost::optional< ::Ifc4x3_rc3::IfcDistributionBoardTypeEnum::Value > Ifc4x3_rc3::IfcDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDistributionBoard::declaration() const { return *IFC4X3_RC3_IfcDistributionBoard_type; }
@@ -15579,7 +15579,7 @@ Ifc4x3_rc3::IfcDistributionBoardType::IfcDistributionBoardType(std::string v1_Gl
 
 // Function implementations for IfcDistributionChamberElement
 boost::optional< ::Ifc4x3_rc3::IfcDistributionChamberElementTypeEnum::Value > Ifc4x3_rc3::IfcDistributionChamberElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDistributionChamberElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDistributionChamberElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDistributionChamberElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDistributionChamberElement::declaration() const { return *IFC4X3_RC3_IfcDistributionChamberElement_type; }
@@ -15658,11 +15658,11 @@ Ifc4x3_rc3::IfcDistributionFlowElementType::IfcDistributionFlowElementType(std::
 
 // Function implementations for IfcDistributionPort
 boost::optional< ::Ifc4x3_rc3::IfcFlowDirectionEnum::Value > Ifc4x3_rc3::IfcDistributionPort::FlowDirection() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcFlowDirectionEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc3::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x3_rc3::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFlowDirectionEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x3_rc3::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFlowDirectionEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcDistributionPortTypeEnum::Value > Ifc4x3_rc3::IfcDistributionPort::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDistributionPortTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDistributionPortTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDistributionPortTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcDistributionSystemEnum::Value > Ifc4x3_rc3::IfcDistributionPort::SystemType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDistributionSystemEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x3_rc3::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x3_rc3::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDistributionPort::declaration() const { return *IFC4X3_RC3_IfcDistributionPort_type; }
@@ -15672,9 +15672,9 @@ Ifc4x3_rc3::IfcDistributionPort::IfcDistributionPort(std::string v1_GlobalId, ::
 
 // Function implementations for IfcDistributionSystem
 boost::optional< std::string > Ifc4x3_rc3::IfcDistributionSystem::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcDistributionSystemEnum::Value > Ifc4x3_rc3::IfcDistributionSystem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDistributionSystemEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc3::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDistributionSystem::declaration() const { return *IFC4X3_RC3_IfcDistributionSystem_type; }
@@ -15688,35 +15688,35 @@ void Ifc4x3_rc3::IfcDocumentInformation::setIdentification(std::string v) { {Ifc
 std::string Ifc4x3_rc3::IfcDocumentInformation::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcDocumentInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::Location() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::Purpose() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::IntendedUse() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::Scope() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::Revision() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcActorSelect* Ifc4x3_rc3::IfcDocumentInformation::DocumentOwner() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc3::IfcActorSelect>(true); }
 void Ifc4x3_rc3::IfcDocumentInformation::setDocumentOwner(::Ifc4x3_rc3::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc3::IfcDocumentInformation::Editors() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::CreationTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::LastRevisionTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::ElectronicFormat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::ValidFrom() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformation::ValidUntil() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc3::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcDocumentConfidentialityEnum::Value > Ifc4x3_rc3::IfcDocumentInformation::Confidentiality() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDocumentConfidentialityEnum::FromString(*data_->getArgument(15)); }
-void Ifc4x3_rc3::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x3_rc3::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDocumentConfidentialityEnum::ToString(*v)));data_->setArgument(15,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x3_rc3::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDocumentConfidentialityEnum::ToString(*v)));}data_->setArgument(15,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcDocumentStatusEnum::Value > Ifc4x3_rc3::IfcDocumentInformation::Status() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDocumentStatusEnum::FromString(*data_->getArgument(16)); }
-void Ifc4x3_rc3::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x3_rc3::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDocumentStatusEnum::ToString(*v)));data_->setArgument(16,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x3_rc3::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDocumentStatusEnum::ToString(*v)));}data_->setArgument(16,attr);} }
 
 ::Ifc4x3_rc3::IfcRelAssociatesDocument::list::ptr Ifc4x3_rc3::IfcDocumentInformation::DocumentInfoForObjects() const { return data_->getInverse(IFC4X3_RC3_IfcRelAssociatesDocument_type, 5)->as<IfcRelAssociatesDocument>(); }
 ::Ifc4x3_rc3::IfcDocumentReference::list::ptr Ifc4x3_rc3::IfcDocumentInformation::HasDocumentReferences() const { return data_->getInverse(IFC4X3_RC3_IfcDocumentReference_type, 4)->as<IfcDocumentReference>(); }
@@ -15734,7 +15734,7 @@ void Ifc4x3_rc3::IfcDocumentInformationRelationship::setRelatingDocument(::Ifc4x
 aggregate_of< ::Ifc4x3_rc3::IfcDocumentInformation >::ptr Ifc4x3_rc3::IfcDocumentInformationRelationship::RelatedDocuments() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc3::IfcDocumentInformation >(); }
 void Ifc4x3_rc3::IfcDocumentInformationRelationship::setRelatedDocuments(aggregate_of< ::Ifc4x3_rc3::IfcDocumentInformation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentInformationRelationship::RelationshipType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDocumentInformationRelationship::declaration() const { return *IFC4X3_RC3_IfcDocumentInformationRelationship_type; }
@@ -15744,7 +15744,7 @@ Ifc4x3_rc3::IfcDocumentInformationRelationship::IfcDocumentInformationRelationsh
 
 // Function implementations for IfcDocumentReference
 boost::optional< std::string > Ifc4x3_rc3::IfcDocumentReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc3::IfcDocumentInformation* Ifc4x3_rc3::IfcDocumentReference::ReferencedDocument() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc3::IfcDocumentInformation>(true); }
 void Ifc4x3_rc3::IfcDocumentReference::setReferencedDocument(::Ifc4x3_rc3::IfcDocumentInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -15757,15 +15757,15 @@ Ifc4x3_rc3::IfcDocumentReference::IfcDocumentReference(boost::optional< std::str
 
 // Function implementations for IfcDoor
 boost::optional< double > Ifc4x3_rc3::IfcDoor::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoor::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcDoorTypeEnum::Value > Ifc4x3_rc3::IfcDoor::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDoorTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDoorTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDoorTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcDoorTypeOperationEnum::Value > Ifc4x3_rc3::IfcDoor::OperationType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc3::IfcDoor::setOperationType(boost::optional< ::Ifc4x3_rc3::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDoorTypeOperationEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcDoor::setOperationType(boost::optional< ::Ifc4x3_rc3::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDoorTypeOperationEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDoor::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDoor::declaration() const { return *IFC4X3_RC3_IfcDoor_type; }
@@ -15775,31 +15775,31 @@ Ifc4x3_rc3::IfcDoor::IfcDoor(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHist
 
 // Function implementations for IfcDoorLiningProperties
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::ThresholdDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::ThresholdThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::TransomThickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::TransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::LiningOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::ThresholdOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::CasingThickness() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::CasingDepth() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 ::Ifc4x3_rc3::IfcShapeAspect* Ifc4x3_rc3::IfcDoorLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(14)))->as<::Ifc4x3_rc3::IfcShapeAspect>(true); }
 void Ifc4x3_rc3::IfcDoorLiningProperties::setShapeAspectStyle(::Ifc4x3_rc3::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc3::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc3::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDoorLiningProperties::declaration() const { return *IFC4X3_RC3_IfcDoorLiningProperties_type; }
@@ -15809,11 +15809,11 @@ Ifc4x3_rc3::IfcDoorLiningProperties::IfcDoorLiningProperties(std::string v1_Glob
 
 // Function implementations for IfcDoorPanelProperties
 boost::optional< double > Ifc4x3_rc3::IfcDoorPanelProperties::PanelDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc3::IfcDoorPanelOperationEnum::Value Ifc4x3_rc3::IfcDoorPanelProperties::PanelOperation() const {  return ::Ifc4x3_rc3::IfcDoorPanelOperationEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc3::IfcDoorPanelProperties::setPanelOperation(::Ifc4x3_rc3::IfcDoorPanelOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcDoorPanelOperationEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcDoorPanelProperties::PanelWidth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc3::IfcDoorPanelPositionEnum::Value Ifc4x3_rc3::IfcDoorPanelProperties::PanelPosition() const {  return ::Ifc4x3_rc3::IfcDoorPanelPositionEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc3::IfcDoorPanelProperties::setPanelPosition(::Ifc4x3_rc3::IfcDoorPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcDoorPanelPositionEnum::ToString(v)));data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcShapeAspect* Ifc4x3_rc3::IfcDoorPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc3::IfcShapeAspect>(true); }
@@ -15855,9 +15855,9 @@ void Ifc4x3_rc3::IfcDoorType::setPredefinedType(::Ifc4x3_rc3::IfcDoorTypeEnum::V
 ::Ifc4x3_rc3::IfcDoorTypeOperationEnum::Value Ifc4x3_rc3::IfcDoorType::OperationType() const {  return ::Ifc4x3_rc3::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc3::IfcDoorType::setOperationType(::Ifc4x3_rc3::IfcDoorTypeOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcDoorTypeOperationEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x3_rc3::IfcDoorType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcDoorType::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDoorType::declaration() const { return *IFC4X3_RC3_IfcDoorType_type; }
@@ -15883,7 +15883,7 @@ Ifc4x3_rc3::IfcDraughtingPreDefinedCurveFont::IfcDraughtingPreDefinedCurveFont(s
 
 // Function implementations for IfcDuctFitting
 boost::optional< ::Ifc4x3_rc3::IfcDuctFittingTypeEnum::Value > Ifc4x3_rc3::IfcDuctFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDuctFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDuctFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDuctFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDuctFitting::declaration() const { return *IFC4X3_RC3_IfcDuctFitting_type; }
@@ -15903,7 +15903,7 @@ Ifc4x3_rc3::IfcDuctFittingType::IfcDuctFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcDuctSegment
 boost::optional< ::Ifc4x3_rc3::IfcDuctSegmentTypeEnum::Value > Ifc4x3_rc3::IfcDuctSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDuctSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDuctSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDuctSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDuctSegment::declaration() const { return *IFC4X3_RC3_IfcDuctSegment_type; }
@@ -15923,7 +15923,7 @@ Ifc4x3_rc3::IfcDuctSegmentType::IfcDuctSegmentType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcDuctSilencer
 boost::optional< ::Ifc4x3_rc3::IfcDuctSilencerTypeEnum::Value > Ifc4x3_rc3::IfcDuctSilencer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDuctSilencerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDuctSilencerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDuctSilencerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcDuctSilencer::declaration() const { return *IFC4X3_RC3_IfcDuctSilencer_type; }
@@ -15943,7 +15943,7 @@ Ifc4x3_rc3::IfcDuctSilencerType::IfcDuctSilencerType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcEarthworksCut
 boost::optional< ::Ifc4x3_rc3::IfcEarthworksCutTypeEnum::Value > Ifc4x3_rc3::IfcEarthworksCut::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcEarthworksCutTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcEarthworksCut::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEarthworksCutTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEarthworksCutTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcEarthworksCut::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEarthworksCutTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEarthworksCutTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcEarthworksCut::declaration() const { return *IFC4X3_RC3_IfcEarthworksCut_type; }
@@ -15961,7 +15961,7 @@ Ifc4x3_rc3::IfcEarthworksElement::IfcEarthworksElement(std::string v1_GlobalId,
 
 // Function implementations for IfcEarthworksFill
 boost::optional< ::Ifc4x3_rc3::IfcEarthworksFillTypeEnum::Value > Ifc4x3_rc3::IfcEarthworksFill::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcEarthworksFillTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcEarthworksFill::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEarthworksFillTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEarthworksFillTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcEarthworksFill::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEarthworksFillTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEarthworksFillTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcEarthworksFill::declaration() const { return *IFC4X3_RC3_IfcEarthworksFill_type; }
@@ -16005,7 +16005,7 @@ Ifc4x3_rc3::IfcEdgeLoop::IfcEdgeLoop(aggregate_of< ::Ifc4x3_rc3::IfcOrientedEdge
 
 // Function implementations for IfcElectricAppliance
 boost::optional< ::Ifc4x3_rc3::IfcElectricApplianceTypeEnum::Value > Ifc4x3_rc3::IfcElectricAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcElectricApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcElectricAppliance::declaration() const { return *IFC4X3_RC3_IfcElectricAppliance_type; }
@@ -16025,7 +16025,7 @@ Ifc4x3_rc3::IfcElectricApplianceType::IfcElectricApplianceType(std::string v1_Gl
 
 // Function implementations for IfcElectricDistributionBoard
 boost::optional< ::Ifc4x3_rc3::IfcElectricDistributionBoardTypeEnum::Value > Ifc4x3_rc3::IfcElectricDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcElectricDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcElectricDistributionBoard::declaration() const { return *IFC4X3_RC3_IfcElectricDistributionBoard_type; }
@@ -16045,7 +16045,7 @@ Ifc4x3_rc3::IfcElectricDistributionBoardType::IfcElectricDistributionBoardType(s
 
 // Function implementations for IfcElectricFlowStorageDevice
 boost::optional< ::Ifc4x3_rc3::IfcElectricFlowStorageDeviceTypeEnum::Value > Ifc4x3_rc3::IfcElectricFlowStorageDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcElectricFlowStorageDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcElectricFlowStorageDevice::declaration() const { return *IFC4X3_RC3_IfcElectricFlowStorageDevice_type; }
@@ -16065,7 +16065,7 @@ Ifc4x3_rc3::IfcElectricFlowStorageDeviceType::IfcElectricFlowStorageDeviceType(s
 
 // Function implementations for IfcElectricFlowTreatmentDevice
 boost::optional< ::Ifc4x3_rc3::IfcElectricFlowTreatmentDeviceTypeEnum::Value > Ifc4x3_rc3::IfcElectricFlowTreatmentDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcElectricFlowTreatmentDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcElectricFlowTreatmentDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricFlowTreatmentDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricFlowTreatmentDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcElectricFlowTreatmentDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricFlowTreatmentDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricFlowTreatmentDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcElectricFlowTreatmentDevice::declaration() const { return *IFC4X3_RC3_IfcElectricFlowTreatmentDevice_type; }
@@ -16085,7 +16085,7 @@ Ifc4x3_rc3::IfcElectricFlowTreatmentDeviceType::IfcElectricFlowTreatmentDeviceTy
 
 // Function implementations for IfcElectricGenerator
 boost::optional< ::Ifc4x3_rc3::IfcElectricGeneratorTypeEnum::Value > Ifc4x3_rc3::IfcElectricGenerator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcElectricGeneratorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricGeneratorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricGeneratorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcElectricGenerator::declaration() const { return *IFC4X3_RC3_IfcElectricGenerator_type; }
@@ -16105,7 +16105,7 @@ Ifc4x3_rc3::IfcElectricGeneratorType::IfcElectricGeneratorType(std::string v1_Gl
 
 // Function implementations for IfcElectricMotor
 boost::optional< ::Ifc4x3_rc3::IfcElectricMotorTypeEnum::Value > Ifc4x3_rc3::IfcElectricMotor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcElectricMotorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricMotorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricMotorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcElectricMotor::declaration() const { return *IFC4X3_RC3_IfcElectricMotor_type; }
@@ -16125,7 +16125,7 @@ Ifc4x3_rc3::IfcElectricMotorType::IfcElectricMotorType(std::string v1_GlobalId,
 
 // Function implementations for IfcElectricTimeControl
 boost::optional< ::Ifc4x3_rc3::IfcElectricTimeControlTypeEnum::Value > Ifc4x3_rc3::IfcElectricTimeControl::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcElectricTimeControlTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricTimeControlTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElectricTimeControlTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcElectricTimeControl::declaration() const { return *IFC4X3_RC3_IfcElectricTimeControl_type; }
@@ -16145,7 +16145,7 @@ Ifc4x3_rc3::IfcElectricTimeControlType::IfcElectricTimeControlType(std::string v
 
 // Function implementations for IfcElement
 boost::optional< std::string > Ifc4x3_rc3::IfcElement::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc3::IfcRelFillsElement::list::ptr Ifc4x3_rc3::IfcElement::FillsVoids() const { return data_->getInverse(IFC4X3_RC3_IfcRelFillsElement_type, 5)->as<IfcRelFillsElement>(); }
 ::Ifc4x3_rc3::IfcRelConnectsElements::list::ptr Ifc4x3_rc3::IfcElement::ConnectedTo() const { return data_->getInverse(IFC4X3_RC3_IfcRelConnectsElements_type, 5)->as<IfcRelConnectsElements>(); }
@@ -16166,9 +16166,9 @@ Ifc4x3_rc3::IfcElement::IfcElement(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwn
 
 // Function implementations for IfcElementAssembly
 boost::optional< ::Ifc4x3_rc3::IfcAssemblyPlaceEnum::Value > Ifc4x3_rc3::IfcElementAssembly::AssemblyPlace() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x3_rc3::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAssemblyPlaceEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x3_rc3::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcAssemblyPlaceEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcElementAssemblyTypeEnum::Value > Ifc4x3_rc3::IfcElementAssembly::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcElementAssemblyTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElementAssemblyTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElementAssemblyTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcElementAssembly::declaration() const { return *IFC4X3_RC3_IfcElementAssembly_type; }
@@ -16204,7 +16204,7 @@ Ifc4x3_rc3::IfcElementComponentType::IfcElementComponentType(std::string v1_Glob
 
 // Function implementations for IfcElementQuantity
 boost::optional< std::string > Ifc4x3_rc3::IfcElementQuantity::MethodOfMeasurement() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x3_rc3::IfcPhysicalQuantity >::ptr Ifc4x3_rc3::IfcElementQuantity::Quantities() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc3::IfcPhysicalQuantity >(); }
 void Ifc4x3_rc3::IfcElementQuantity::setQuantities(aggregate_of< ::Ifc4x3_rc3::IfcPhysicalQuantity >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -16216,7 +16216,7 @@ Ifc4x3_rc3::IfcElementQuantity::IfcElementQuantity(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcElementType
 boost::optional< std::string > Ifc4x3_rc3::IfcElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcElementType::declaration() const { return *IFC4X3_RC3_IfcElementType_type; }
@@ -16276,7 +16276,7 @@ Ifc4x3_rc3::IfcEnergyConversionDeviceType::IfcEnergyConversionDeviceType(std::st
 
 // Function implementations for IfcEngine
 boost::optional< ::Ifc4x3_rc3::IfcEngineTypeEnum::Value > Ifc4x3_rc3::IfcEngine::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcEngineTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEngineTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEngineTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcEngine::declaration() const { return *IFC4X3_RC3_IfcEngine_type; }
@@ -16296,7 +16296,7 @@ Ifc4x3_rc3::IfcEngineType::IfcEngineType(std::string v1_GlobalId, ::Ifc4x3_rc3::
 
 // Function implementations for IfcEvaporativeCooler
 boost::optional< ::Ifc4x3_rc3::IfcEvaporativeCoolerTypeEnum::Value > Ifc4x3_rc3::IfcEvaporativeCooler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcEvaporativeCoolerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEvaporativeCoolerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEvaporativeCoolerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcEvaporativeCooler::declaration() const { return *IFC4X3_RC3_IfcEvaporativeCooler_type; }
@@ -16316,7 +16316,7 @@ Ifc4x3_rc3::IfcEvaporativeCoolerType::IfcEvaporativeCoolerType(std::string v1_Gl
 
 // Function implementations for IfcEvaporator
 boost::optional< ::Ifc4x3_rc3::IfcEvaporatorTypeEnum::Value > Ifc4x3_rc3::IfcEvaporator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcEvaporatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEvaporatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEvaporatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcEvaporator::declaration() const { return *IFC4X3_RC3_IfcEvaporator_type; }
@@ -16336,11 +16336,11 @@ Ifc4x3_rc3::IfcEvaporatorType::IfcEvaporatorType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcEvent
 boost::optional< ::Ifc4x3_rc3::IfcEventTypeEnum::Value > Ifc4x3_rc3::IfcEvent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcEventTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc3::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEventTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEventTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcEventTriggerTypeEnum::Value > Ifc4x3_rc3::IfcEvent::EventTriggerType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x3_rc3::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEventTriggerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x3_rc3::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcEventTriggerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcEvent::UserDefinedEventTriggerType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 ::Ifc4x3_rc3::IfcEventTime* Ifc4x3_rc3::IfcEvent::EventOccurenceTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc3::IfcEventTime>(true); }
 void Ifc4x3_rc3::IfcEvent::setEventOccurenceTime(::Ifc4x3_rc3::IfcEventTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -16352,13 +16352,13 @@ Ifc4x3_rc3::IfcEvent::IfcEvent(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHi
 
 // Function implementations for IfcEventTime
 boost::optional< std::string > Ifc4x3_rc3::IfcEventTime::ActualDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcEventTime::EarlyDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcEventTime::LateDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcEventTime::ScheduleDate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcEventTime::declaration() const { return *IFC4X3_RC3_IfcEventTime_type; }
@@ -16372,7 +16372,7 @@ void Ifc4x3_rc3::IfcEventType::setPredefinedType(::Ifc4x3_rc3::IfcEventTypeEnum:
 ::Ifc4x3_rc3::IfcEventTriggerTypeEnum::Value Ifc4x3_rc3::IfcEventType::EventTriggerType() const {  return ::Ifc4x3_rc3::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc3::IfcEventType::setEventTriggerType(::Ifc4x3_rc3::IfcEventTriggerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcEventTriggerTypeEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcEventType::UserDefinedEventTriggerType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcEventType::declaration() const { return *IFC4X3_RC3_IfcEventType_type; }
@@ -16382,9 +16382,9 @@ Ifc4x3_rc3::IfcEventType::IfcEventType(std::string v1_GlobalId, ::Ifc4x3_rc3::If
 
 // Function implementations for IfcExtendedProperties
 boost::optional< std::string > Ifc4x3_rc3::IfcExtendedProperties::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcExtendedProperties::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc3::IfcProperty >::ptr Ifc4x3_rc3::IfcExtendedProperties::Properties() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc3::IfcProperty >(); }
 void Ifc4x3_rc3::IfcExtendedProperties::setProperties(aggregate_of< ::Ifc4x3_rc3::IfcProperty >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -16404,11 +16404,11 @@ Ifc4x3_rc3::IfcExternalInformation::IfcExternalInformation() : IfcUtil::IfcBaseE
 
 // Function implementations for IfcExternalReference
 boost::optional< std::string > Ifc4x3_rc3::IfcExternalReference::Location() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcExternalReference::Identification() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcExternalReference::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc3::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc3::IfcExternalReference::ExternalReferenceForResources() const { return data_->getInverse(IFC4X3_RC3_IfcExternalReferenceRelationship_type, 2)->as<IfcExternalReferenceRelationship>(); }
 
@@ -16431,7 +16431,7 @@ Ifc4x3_rc3::IfcExternalReferenceRelationship::IfcExternalReferenceRelationship(b
 
 // Function implementations for IfcExternalSpatialElement
 boost::optional< ::Ifc4x3_rc3::IfcExternalSpatialElementTypeEnum::Value > Ifc4x3_rc3::IfcExternalSpatialElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcExternalSpatialElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcExternalSpatialElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcExternalSpatialElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc3::IfcRelSpaceBoundary::list::ptr Ifc4x3_rc3::IfcExternalSpatialElement::BoundedBy() const { return data_->getInverse(IFC4X3_RC3_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
 
@@ -16587,17 +16587,17 @@ Ifc4x3_rc3::IfcFacilityPart::IfcFacilityPart(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcFailureConnectionCondition
 boost::optional< double > Ifc4x3_rc3::IfcFailureConnectionCondition::TensionFailureX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcFailureConnectionCondition::TensionFailureY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcFailureConnectionCondition::TensionFailureZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcFailureConnectionCondition::CompressionFailureX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcFailureConnectionCondition::CompressionFailureY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcFailureConnectionCondition::CompressionFailureZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFailureConnectionCondition::declaration() const { return *IFC4X3_RC3_IfcFailureConnectionCondition_type; }
@@ -16607,7 +16607,7 @@ Ifc4x3_rc3::IfcFailureConnectionCondition::IfcFailureConnectionCondition(boost::
 
 // Function implementations for IfcFan
 boost::optional< ::Ifc4x3_rc3::IfcFanTypeEnum::Value > Ifc4x3_rc3::IfcFan::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcFanTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcFan::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFanTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcFan::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFanTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFan::declaration() const { return *IFC4X3_RC3_IfcFan_type; }
@@ -16627,7 +16627,7 @@ Ifc4x3_rc3::IfcFanType::IfcFanType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwn
 
 // Function implementations for IfcFastener
 boost::optional< ::Ifc4x3_rc3::IfcFastenerTypeEnum::Value > Ifc4x3_rc3::IfcFastener::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcFastenerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFastenerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFastenerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFastener::declaration() const { return *IFC4X3_RC3_IfcFastener_type; }
@@ -16675,7 +16675,7 @@ Ifc4x3_rc3::IfcFeatureElementSubtraction::IfcFeatureElementSubtraction(std::stri
 aggregate_of_instance::ptr Ifc4x3_rc3::IfcFillAreaStyle::FillStyles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcFillAreaStyle::setFillStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc3::IfcFillAreaStyle::ModelOrDraughting() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcFillAreaStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcFillAreaStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFillAreaStyle::declaration() const { return *IFC4X3_RC3_IfcFillAreaStyle_type; }
@@ -16717,7 +16717,7 @@ Ifc4x3_rc3::IfcFillAreaStyleTiles::IfcFillAreaStyleTiles(aggregate_of< ::Ifc4x3_
 
 // Function implementations for IfcFilter
 boost::optional< ::Ifc4x3_rc3::IfcFilterTypeEnum::Value > Ifc4x3_rc3::IfcFilter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcFilterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFilterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFilterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFilter::declaration() const { return *IFC4X3_RC3_IfcFilter_type; }
@@ -16737,7 +16737,7 @@ Ifc4x3_rc3::IfcFilterType::IfcFilterType(std::string v1_GlobalId, ::Ifc4x3_rc3::
 
 // Function implementations for IfcFireSuppressionTerminal
 boost::optional< ::Ifc4x3_rc3::IfcFireSuppressionTerminalTypeEnum::Value > Ifc4x3_rc3::IfcFireSuppressionTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcFireSuppressionTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFireSuppressionTerminal::declaration() const { return *IFC4X3_RC3_IfcFireSuppressionTerminal_type; }
@@ -16799,7 +16799,7 @@ Ifc4x3_rc3::IfcFlowFittingType::IfcFlowFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcFlowInstrument
 boost::optional< ::Ifc4x3_rc3::IfcFlowInstrumentTypeEnum::Value > Ifc4x3_rc3::IfcFlowInstrument::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcFlowInstrumentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFlowInstrumentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFlowInstrumentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFlowInstrument::declaration() const { return *IFC4X3_RC3_IfcFlowInstrument_type; }
@@ -16819,7 +16819,7 @@ Ifc4x3_rc3::IfcFlowInstrumentType::IfcFlowInstrumentType(std::string v1_GlobalId
 
 // Function implementations for IfcFlowMeter
 boost::optional< ::Ifc4x3_rc3::IfcFlowMeterTypeEnum::Value > Ifc4x3_rc3::IfcFlowMeter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcFlowMeterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFlowMeterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFlowMeterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFlowMeter::declaration() const { return *IFC4X3_RC3_IfcFlowMeter_type; }
@@ -16919,7 +16919,7 @@ Ifc4x3_rc3::IfcFlowTreatmentDeviceType::IfcFlowTreatmentDeviceType(std::string v
 
 // Function implementations for IfcFooting
 boost::optional< ::Ifc4x3_rc3::IfcFootingTypeEnum::Value > Ifc4x3_rc3::IfcFooting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcFootingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFootingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFootingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFooting::declaration() const { return *IFC4X3_RC3_IfcFooting_type; }
@@ -16955,7 +16955,7 @@ Ifc4x3_rc3::IfcFurnishingElementType::IfcFurnishingElementType(std::string v1_Gl
 
 // Function implementations for IfcFurniture
 boost::optional< ::Ifc4x3_rc3::IfcFurnitureTypeEnum::Value > Ifc4x3_rc3::IfcFurniture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcFurnitureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFurniture::declaration() const { return *IFC4X3_RC3_IfcFurniture_type; }
@@ -16967,7 +16967,7 @@ Ifc4x3_rc3::IfcFurniture::IfcFurniture(std::string v1_GlobalId, ::Ifc4x3_rc3::If
 ::Ifc4x3_rc3::IfcAssemblyPlaceEnum::Value Ifc4x3_rc3::IfcFurnitureType::AssemblyPlace() const {  return ::Ifc4x3_rc3::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc3::IfcFurnitureType::setAssemblyPlace(::Ifc4x3_rc3::IfcAssemblyPlaceEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcAssemblyPlaceEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcFurnitureTypeEnum::Value > Ifc4x3_rc3::IfcFurnitureType::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcFurnitureTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcFurnitureType::declaration() const { return *IFC4X3_RC3_IfcFurnitureType_type; }
@@ -16977,7 +16977,7 @@ Ifc4x3_rc3::IfcFurnitureType::IfcFurnitureType(std::string v1_GlobalId, ::Ifc4x3
 
 // Function implementations for IfcGeographicElement
 boost::optional< ::Ifc4x3_rc3::IfcGeographicElementTypeEnum::Value > Ifc4x3_rc3::IfcGeographicElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcGeographicElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcGeographicElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcGeographicElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcGeographicElement::declaration() const { return *IFC4X3_RC3_IfcGeographicElement_type; }
@@ -17007,7 +17007,7 @@ Ifc4x3_rc3::IfcGeometricCurveSet::IfcGeometricCurveSet(aggregate_of_instance::pt
 int Ifc4x3_rc3::IfcGeometricRepresentationContext::CoordinateSpaceDimension() const {  int v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc3::IfcGeometricRepresentationContext::setCoordinateSpaceDimension(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcGeometricRepresentationContext::Precision() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc3::IfcAxis2Placement* Ifc4x3_rc3::IfcGeometricRepresentationContext::WorldCoordinateSystem() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc3::IfcAxis2Placement>(true); }
 void Ifc4x3_rc3::IfcGeometricRepresentationContext::setWorldCoordinateSystem(::Ifc4x3_rc3::IfcAxis2Placement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 ::Ifc4x3_rc3::IfcDirection* Ifc4x3_rc3::IfcGeometricRepresentationContext::TrueNorth() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc3::IfcDirection>(true); }
@@ -17033,11 +17033,11 @@ Ifc4x3_rc3::IfcGeometricRepresentationItem::IfcGeometricRepresentationItem() : I
 ::Ifc4x3_rc3::IfcGeometricRepresentationContext* Ifc4x3_rc3::IfcGeometricRepresentationSubContext::ParentContext() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcGeometricRepresentationContext>(true); }
 void Ifc4x3_rc3::IfcGeometricRepresentationSubContext::setParentContext(::Ifc4x3_rc3::IfcGeometricRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcGeometricRepresentationSubContext::TargetScale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcGeometricProjectionEnum::Value Ifc4x3_rc3::IfcGeometricRepresentationSubContext::TargetView() const {  return ::Ifc4x3_rc3::IfcGeometricProjectionEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc3::IfcGeometricRepresentationSubContext::setTargetView(::Ifc4x3_rc3::IfcGeometricProjectionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcGeometricProjectionEnum::ToString(v)));data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcGeometricRepresentationSubContext::UserDefinedTargetView() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcGeometricRepresentationSubContext::declaration() const { return *IFC4X3_RC3_IfcGeometricRepresentationSubContext_type; }
@@ -17113,9 +17113,9 @@ void Ifc4x3_rc3::IfcGrid::setUAxes(aggregate_of< ::Ifc4x3_rc3::IfcGridAxis >::pt
 aggregate_of< ::Ifc4x3_rc3::IfcGridAxis >::ptr Ifc4x3_rc3::IfcGrid::VAxes() const {  aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc3::IfcGridAxis >(); }
 void Ifc4x3_rc3::IfcGrid::setVAxes(aggregate_of< ::Ifc4x3_rc3::IfcGridAxis >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcGridAxis >::ptr > Ifc4x3_rc3::IfcGrid::WAxes() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc3::IfcGridAxis >(); }
-void Ifc4x3_rc3::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcGridTypeEnum::Value > Ifc4x3_rc3::IfcGrid::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcGridTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcGridTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcGridTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcGrid::declaration() const { return *IFC4X3_RC3_IfcGrid_type; }
@@ -17125,7 +17125,7 @@ Ifc4x3_rc3::IfcGrid::IfcGrid(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHist
 
 // Function implementations for IfcGridAxis
 boost::optional< std::string > Ifc4x3_rc3::IfcGridAxis::AxisTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc3::IfcCurve* Ifc4x3_rc3::IfcGridAxis::AxisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc3::IfcCurve>(true); }
 void Ifc4x3_rc3::IfcGridAxis::setAxisCurve(::Ifc4x3_rc3::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 bool Ifc4x3_rc3::IfcGridAxis::SameSense() const {  bool v = *data_->getArgument(2); return v; }
@@ -17176,7 +17176,7 @@ Ifc4x3_rc3::IfcHalfSpaceSolid::IfcHalfSpaceSolid(::Ifc4x3_rc3::IfcSurface* v1_Ba
 
 // Function implementations for IfcHeatExchanger
 boost::optional< ::Ifc4x3_rc3::IfcHeatExchangerTypeEnum::Value > Ifc4x3_rc3::IfcHeatExchanger::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcHeatExchangerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcHeatExchangerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcHeatExchangerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcHeatExchanger::declaration() const { return *IFC4X3_RC3_IfcHeatExchanger_type; }
@@ -17196,7 +17196,7 @@ Ifc4x3_rc3::IfcHeatExchangerType::IfcHeatExchangerType(std::string v1_GlobalId,
 
 // Function implementations for IfcHumidifier
 boost::optional< ::Ifc4x3_rc3::IfcHumidifierTypeEnum::Value > Ifc4x3_rc3::IfcHumidifier::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcHumidifierTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcHumidifierTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcHumidifierTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcHumidifier::declaration() const { return *IFC4X3_RC3_IfcHumidifier_type; }
@@ -17224,11 +17224,11 @@ void Ifc4x3_rc3::IfcIShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc3::IfcIShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcIShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcIShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcIShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcIShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcIShapeProfileDef::declaration() const { return *IFC4X3_RC3_IfcIShapeProfileDef_type; }
@@ -17268,7 +17268,7 @@ Ifc4x3_rc3::IfcImpactProtectionDeviceType::IfcImpactProtectionDeviceType(std::st
 
 // Function implementations for IfcInclinedReferenceSweptAreaSolid
 boost::optional< bool > Ifc4x3_rc3::IfcInclinedReferenceSweptAreaSolid::FixedAxisVertical() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } bool v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcInclinedReferenceSweptAreaSolid::setFixedAxisVertical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcInclinedReferenceSweptAreaSolid::setFixedAxisVertical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcInclinedReferenceSweptAreaSolid::declaration() const { return *IFC4X3_RC3_IfcInclinedReferenceSweptAreaSolid_type; }
@@ -17280,7 +17280,7 @@ Ifc4x3_rc3::IfcInclinedReferenceSweptAreaSolid::IfcInclinedReferenceSweptAreaSol
 ::Ifc4x3_rc3::IfcTessellatedFaceSet* Ifc4x3_rc3::IfcIndexedColourMap::MappedTo() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc3::IfcTessellatedFaceSet>(true); }
 void Ifc4x3_rc3::IfcIndexedColourMap::setMappedTo(::Ifc4x3_rc3::IfcTessellatedFaceSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcIndexedColourMap::Opacity() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc3::IfcColourRgbList* Ifc4x3_rc3::IfcIndexedColourMap::Colours() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc3::IfcColourRgbList>(true); }
 void Ifc4x3_rc3::IfcIndexedColourMap::setColours(::Ifc4x3_rc3::IfcColourRgbList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::vector< int > /*[1:?]*/ Ifc4x3_rc3::IfcIndexedColourMap::ColourIndex() const {  std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
@@ -17296,9 +17296,9 @@ Ifc4x3_rc3::IfcIndexedColourMap::IfcIndexedColourMap(::Ifc4x3_rc3::IfcTessellate
 ::Ifc4x3_rc3::IfcCartesianPointList* Ifc4x3_rc3::IfcIndexedPolyCurve::Points() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc3::IfcCartesianPointList>(true); }
 void Ifc4x3_rc3::IfcIndexedPolyCurve::setPoints(::Ifc4x3_rc3::IfcCartesianPointList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc3::IfcIndexedPolyCurve::Segments() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc3::IfcIndexedPolyCurve::SelfIntersect() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcIndexedPolyCurve::declaration() const { return *IFC4X3_RC3_IfcIndexedPolyCurve_type; }
@@ -17341,7 +17341,7 @@ Ifc4x3_rc3::IfcIndexedTextureMap::IfcIndexedTextureMap(aggregate_of< ::Ifc4x3_rc
 
 // Function implementations for IfcIndexedTriangleTextureMap
 boost::optional< std::vector< std::vector< int > > > Ifc4x3_rc3::IfcIndexedTriangleTextureMap::TexCoordIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcIndexedTriangleTextureMap::declaration() const { return *IFC4X3_RC3_IfcIndexedTriangleTextureMap_type; }
@@ -17351,7 +17351,7 @@ Ifc4x3_rc3::IfcIndexedTriangleTextureMap::IfcIndexedTriangleTextureMap(aggregate
 
 // Function implementations for IfcInterceptor
 boost::optional< ::Ifc4x3_rc3::IfcInterceptorTypeEnum::Value > Ifc4x3_rc3::IfcInterceptor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcInterceptorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcInterceptorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcInterceptorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcInterceptor::declaration() const { return *IFC4X3_RC3_IfcInterceptor_type; }
@@ -17379,13 +17379,13 @@ Ifc4x3_rc3::IfcIntersectionCurve::IfcIntersectionCurve(::Ifc4x3_rc3::IfcCurve* v
 
 // Function implementations for IfcInventory
 boost::optional< ::Ifc4x3_rc3::IfcInventoryTypeEnum::Value > Ifc4x3_rc3::IfcInventory::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcInventoryTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc3::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcInventoryTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcInventoryTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc3::IfcActorSelect* Ifc4x3_rc3::IfcInventory::Jurisdiction() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcActorSelect>(true); }
 void Ifc4x3_rc3::IfcInventory::setJurisdiction(::Ifc4x3_rc3::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPerson >::ptr > Ifc4x3_rc3::IfcInventory::ResponsiblePersons() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc3::IfcPerson >(); }
-void Ifc4x3_rc3::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcInventory::LastUpdateDate() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc3::IfcCostValue* Ifc4x3_rc3::IfcInventory::CurrentValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc3::IfcCostValue>(true); }
 void Ifc4x3_rc3::IfcInventory::setCurrentValue(::Ifc4x3_rc3::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x3_rc3::IfcCostValue* Ifc4x3_rc3::IfcInventory::OriginalValue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc3::IfcCostValue>(true); }
@@ -17421,7 +17421,7 @@ Ifc4x3_rc3::IfcIrregularTimeSeriesValue::IfcIrregularTimeSeriesValue(std::string
 
 // Function implementations for IfcJunctionBox
 boost::optional< ::Ifc4x3_rc3::IfcJunctionBoxTypeEnum::Value > Ifc4x3_rc3::IfcJunctionBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcJunctionBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcJunctionBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcJunctionBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcJunctionBox::declaration() const { return *IFC4X3_RC3_IfcJunctionBox_type; }
@@ -17463,15 +17463,15 @@ Ifc4x3_rc3::IfcKerbType::IfcKerbType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 double Ifc4x3_rc3::IfcLShapeProfileDef::Depth() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcLShapeProfileDef::setDepth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcLShapeProfileDef::Width() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 double Ifc4x3_rc3::IfcLShapeProfileDef::Thickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc3::IfcLShapeProfileDef::setThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcLShapeProfileDef::FilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcLShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcLShapeProfileDef::LegSlope() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcLShapeProfileDef::declaration() const { return *IFC4X3_RC3_IfcLShapeProfileDef_type; }
@@ -17481,7 +17481,7 @@ Ifc4x3_rc3::IfcLShapeProfileDef::IfcLShapeProfileDef(::Ifc4x3_rc3::IfcProfileTyp
 
 // Function implementations for IfcLaborResource
 boost::optional< ::Ifc4x3_rc3::IfcLaborResourceTypeEnum::Value > Ifc4x3_rc3::IfcLaborResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcLaborResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcLaborResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcLaborResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcLaborResource::declaration() const { return *IFC4X3_RC3_IfcLaborResource_type; }
@@ -17513,7 +17513,7 @@ Ifc4x3_rc3::IfcLagTime::IfcLagTime(boost::optional< std::string > v1_Name, boost
 
 // Function implementations for IfcLamp
 boost::optional< ::Ifc4x3_rc3::IfcLampTypeEnum::Value > Ifc4x3_rc3::IfcLamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcLampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcLampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcLampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcLamp::declaration() const { return *IFC4X3_RC3_IfcLamp_type; }
@@ -17535,15 +17535,15 @@ Ifc4x3_rc3::IfcLampType::IfcLampType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 std::string Ifc4x3_rc3::IfcLibraryInformation::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc3::IfcLibraryInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcLibraryInformation::Version() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc3::IfcActorSelect* Ifc4x3_rc3::IfcLibraryInformation::Publisher() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc3::IfcActorSelect>(true); }
 void Ifc4x3_rc3::IfcLibraryInformation::setPublisher(::Ifc4x3_rc3::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcLibraryInformation::VersionDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcLibraryInformation::Location() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcLibraryInformation::Description() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc3::IfcRelAssociatesLibrary::list::ptr Ifc4x3_rc3::IfcLibraryInformation::LibraryInfoForObjects() const { return data_->getInverse(IFC4X3_RC3_IfcRelAssociatesLibrary_type, 5)->as<IfcRelAssociatesLibrary>(); }
 ::Ifc4x3_rc3::IfcLibraryReference::list::ptr Ifc4x3_rc3::IfcLibraryInformation::HasLibraryReferences() const { return data_->getInverse(IFC4X3_RC3_IfcLibraryReference_type, 5)->as<IfcLibraryReference>(); }
@@ -17555,9 +17555,9 @@ Ifc4x3_rc3::IfcLibraryInformation::IfcLibraryInformation(std::string v1_Name, bo
 
 // Function implementations for IfcLibraryReference
 boost::optional< std::string > Ifc4x3_rc3::IfcLibraryReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcLibraryReference::Language() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc3::IfcLibraryInformation* Ifc4x3_rc3::IfcLibraryReference::ReferencedLibrary() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc3::IfcLibraryInformation>(true); }
 void Ifc4x3_rc3::IfcLibraryReference::setReferencedLibrary(::Ifc4x3_rc3::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -17584,7 +17584,7 @@ Ifc4x3_rc3::IfcLightDistributionData::IfcLightDistributionData(double v1_MainPla
 
 // Function implementations for IfcLightFixture
 boost::optional< ::Ifc4x3_rc3::IfcLightFixtureTypeEnum::Value > Ifc4x3_rc3::IfcLightFixture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcLightFixtureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcLightFixtureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcLightFixtureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcLightFixture::declaration() const { return *IFC4X3_RC3_IfcLightFixture_type; }
@@ -17616,13 +17616,13 @@ Ifc4x3_rc3::IfcLightIntensityDistribution::IfcLightIntensityDistribution(::Ifc4x
 
 // Function implementations for IfcLightSource
 boost::optional< std::string > Ifc4x3_rc3::IfcLightSource::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc3::IfcColourRgb* Ifc4x3_rc3::IfcLightSource::LightColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc3::IfcColourRgb>(true); }
 void Ifc4x3_rc3::IfcLightSource::setLightColour(::Ifc4x3_rc3::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcLightSource::AmbientIntensity() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcLightSource::Intensity() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcLightSource::declaration() const { return *IFC4X3_RC3_IfcLightSource_type; }
@@ -17690,7 +17690,7 @@ Ifc4x3_rc3::IfcLightSourcePositional::IfcLightSourcePositional(boost::optional<
 ::Ifc4x3_rc3::IfcDirection* Ifc4x3_rc3::IfcLightSourceSpot::Orientation() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc3::IfcDirection>(true); }
 void Ifc4x3_rc3::IfcLightSourceSpot::setOrientation(::Ifc4x3_rc3::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcLightSourceSpot::ConcentrationExponent() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 double Ifc4x3_rc3::IfcLightSourceSpot::SpreadAngle() const {  double v = *data_->getArgument(11); return v; }
 void Ifc4x3_rc3::IfcLightSourceSpot::setSpreadAngle(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 double Ifc4x3_rc3::IfcLightSourceSpot::BeamWidthAngle() const {  double v = *data_->getArgument(12); return v; }
@@ -17744,7 +17744,7 @@ Ifc4x3_rc3::IfcLinearPositioningElement::IfcLinearPositioningElement(std::string
 
 // Function implementations for IfcLiquidTerminal
 boost::optional< ::Ifc4x3_rc3::IfcLiquidTerminalTypeEnum::Value > Ifc4x3_rc3::IfcLiquidTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcLiquidTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcLiquidTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcLiquidTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcLiquidTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcLiquidTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcLiquidTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcLiquidTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcLiquidTerminal::declaration() const { return *IFC4X3_RC3_IfcLiquidTerminal_type; }
@@ -17798,15 +17798,15 @@ void Ifc4x3_rc3::IfcMapConversion::setNorthings(double v) { {IfcWrite::IfcWriteA
 double Ifc4x3_rc3::IfcMapConversion::OrthogonalHeight() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc3::IfcMapConversion::setOrthogonalHeight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMapConversion::XAxisAbscissa() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMapConversion::XAxisOrdinate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMapConversion::Scale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMapConversion::ScaleY() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcMapConversion::setScaleY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcMapConversion::setScaleY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMapConversion::ScaleZ() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcMapConversion::setScaleZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcMapConversion::setScaleZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMapConversion::declaration() const { return *IFC4X3_RC3_IfcMapConversion_type; }
@@ -17828,7 +17828,7 @@ Ifc4x3_rc3::IfcMappedItem::IfcMappedItem(::Ifc4x3_rc3::IfcRepresentationMap* v1_
 
 // Function implementations for IfcMarineFacility
 boost::optional< ::Ifc4x3_rc3::IfcMarineFacilityTypeEnum::Value > Ifc4x3_rc3::IfcMarineFacility::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcMarineFacilityTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcMarineFacility::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMarineFacilityTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMarineFacilityTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcMarineFacility::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMarineFacilityTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMarineFacilityTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMarineFacility::declaration() const { return *IFC4X3_RC3_IfcMarineFacility_type; }
@@ -17840,9 +17840,9 @@ Ifc4x3_rc3::IfcMarineFacility::IfcMarineFacility(std::string v1_GlobalId, ::Ifc4
 std::string Ifc4x3_rc3::IfcMaterial::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc3::IfcMaterial::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterial::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterial::Category() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc3::IfcMaterialDefinitionRepresentation::list::ptr Ifc4x3_rc3::IfcMaterial::HasRepresentation() const { return data_->getInverse(IFC4X3_RC3_IfcMaterialDefinitionRepresentation_type, 3)->as<IfcMaterialDefinitionRepresentation>(); }
 ::Ifc4x3_rc3::IfcMaterialRelationship::list::ptr Ifc4x3_rc3::IfcMaterial::IsRelatedWith() const { return data_->getInverse(IFC4X3_RC3_IfcMaterialRelationship_type, 3)->as<IfcMaterialRelationship>(); }
@@ -17867,15 +17867,15 @@ Ifc4x3_rc3::IfcMaterialClassificationRelationship::IfcMaterialClassificationRela
 
 // Function implementations for IfcMaterialConstituent
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialConstituent::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialConstituent::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc3::IfcMaterial* Ifc4x3_rc3::IfcMaterialConstituent::Material() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc3::IfcMaterial>(true); }
 void Ifc4x3_rc3::IfcMaterialConstituent::setMaterial(::Ifc4x3_rc3::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMaterialConstituent::Fraction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialConstituent::Category() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc3::IfcMaterialConstituentSet::list::ptr Ifc4x3_rc3::IfcMaterialConstituent::ToMaterialConstituentSet() const { return data_->getInverse(IFC4X3_RC3_IfcMaterialConstituentSet_type, 2)->as<IfcMaterialConstituentSet>(); }
 
@@ -17886,11 +17886,11 @@ Ifc4x3_rc3::IfcMaterialConstituent::IfcMaterialConstituent(boost::optional< std:
 
 // Function implementations for IfcMaterialConstituentSet
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialConstituentSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialConstituentSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcMaterialConstituent >::ptr > Ifc4x3_rc3::IfcMaterialConstituentSet::MaterialConstituents() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc3::IfcMaterialConstituent >(); }
-void Ifc4x3_rc3::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMaterialConstituentSet::declaration() const { return *IFC4X3_RC3_IfcMaterialConstituentSet_type; }
@@ -17925,15 +17925,15 @@ void Ifc4x3_rc3::IfcMaterialLayer::setMaterial(::Ifc4x3_rc3::IfcMaterial* v) { {
 double Ifc4x3_rc3::IfcMaterialLayer::LayerThickness() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcMaterialLayer::setLayerThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< boost::logic::tribool > Ifc4x3_rc3::IfcMaterialLayer::IsVentilated() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } boost::logic::tribool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialLayer::Name() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialLayer::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialLayer::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x3_rc3::IfcMaterialLayer::Priority() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc3::IfcMaterialLayerSet::list::ptr Ifc4x3_rc3::IfcMaterialLayer::ToMaterialLayerSet() const { return data_->getInverse(IFC4X3_RC3_IfcMaterialLayerSet_type, 0)->as<IfcMaterialLayerSet>(); }
 
@@ -17946,9 +17946,9 @@ Ifc4x3_rc3::IfcMaterialLayer::IfcMaterialLayer(::Ifc4x3_rc3::IfcMaterial* v1_Mat
 aggregate_of< ::Ifc4x3_rc3::IfcMaterialLayer >::ptr Ifc4x3_rc3::IfcMaterialLayerSet::MaterialLayers() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x3_rc3::IfcMaterialLayer >(); }
 void Ifc4x3_rc3::IfcMaterialLayerSet::setMaterialLayers(aggregate_of< ::Ifc4x3_rc3::IfcMaterialLayer >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialLayerSet::LayerSetName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialLayerSet::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMaterialLayerSet::declaration() const { return *IFC4X3_RC3_IfcMaterialLayerSet_type; }
@@ -17966,7 +17966,7 @@ void Ifc4x3_rc3::IfcMaterialLayerSetUsage::setDirectionSense(::Ifc4x3_rc3::IfcDi
 double Ifc4x3_rc3::IfcMaterialLayerSetUsage::OffsetFromReferenceLine() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcMaterialLayerSetUsage::setOffsetFromReferenceLine(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMaterialLayerSetUsage::ReferenceExtent() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMaterialLayerSetUsage::declaration() const { return *IFC4X3_RC3_IfcMaterialLayerSetUsage_type; }
@@ -17998,17 +17998,17 @@ Ifc4x3_rc3::IfcMaterialList::IfcMaterialList(aggregate_of< ::Ifc4x3_rc3::IfcMate
 
 // Function implementations for IfcMaterialProfile
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialProfile::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialProfile::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc3::IfcMaterial* Ifc4x3_rc3::IfcMaterialProfile::Material() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc3::IfcMaterial>(true); }
 void Ifc4x3_rc3::IfcMaterialProfile::setMaterial(::Ifc4x3_rc3::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcProfileDef* Ifc4x3_rc3::IfcMaterialProfile::Profile() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcProfileDef>(true); }
 void Ifc4x3_rc3::IfcMaterialProfile::setProfile(::Ifc4x3_rc3::IfcProfileDef* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc3::IfcMaterialProfile::Priority() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialProfile::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc3::IfcMaterialProfileSet::list::ptr Ifc4x3_rc3::IfcMaterialProfile::ToMaterialProfileSet() const { return data_->getInverse(IFC4X3_RC3_IfcMaterialProfileSet_type, 2)->as<IfcMaterialProfileSet>(); }
 
@@ -18019,9 +18019,9 @@ Ifc4x3_rc3::IfcMaterialProfile::IfcMaterialProfile(boost::optional< std::string
 
 // Function implementations for IfcMaterialProfileSet
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialProfileSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialProfileSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc3::IfcMaterialProfile >::ptr Ifc4x3_rc3::IfcMaterialProfileSet::MaterialProfiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc3::IfcMaterialProfile >(); }
 void Ifc4x3_rc3::IfcMaterialProfileSet::setMaterialProfiles(aggregate_of< ::Ifc4x3_rc3::IfcMaterialProfile >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcCompositeProfileDef* Ifc4x3_rc3::IfcMaterialProfileSet::CompositeProfile() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcCompositeProfileDef>(true); }
@@ -18037,9 +18037,9 @@ Ifc4x3_rc3::IfcMaterialProfileSet::IfcMaterialProfileSet(boost::optional< std::s
 ::Ifc4x3_rc3::IfcMaterialProfileSet* Ifc4x3_rc3::IfcMaterialProfileSetUsage::ForProfileSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc3::IfcMaterialProfileSet>(true); }
 void Ifc4x3_rc3::IfcMaterialProfileSetUsage::setForProfileSet(::Ifc4x3_rc3::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< int > Ifc4x3_rc3::IfcMaterialProfileSetUsage::CardinalPoint() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } int v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMaterialProfileSetUsage::ReferenceExtent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMaterialProfileSetUsage::declaration() const { return *IFC4X3_RC3_IfcMaterialProfileSetUsage_type; }
@@ -18051,7 +18051,7 @@ Ifc4x3_rc3::IfcMaterialProfileSetUsage::IfcMaterialProfileSetUsage(::Ifc4x3_rc3:
 ::Ifc4x3_rc3::IfcMaterialProfileSet* Ifc4x3_rc3::IfcMaterialProfileSetUsageTapering::ForProfileEndSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcMaterialProfileSet>(true); }
 void Ifc4x3_rc3::IfcMaterialProfileSetUsageTapering::setForProfileEndSet(::Ifc4x3_rc3::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc3::IfcMaterialProfileSetUsageTapering::CardinalEndPoint() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMaterialProfileSetUsageTapering::declaration() const { return *IFC4X3_RC3_IfcMaterialProfileSetUsageTapering_type; }
@@ -18085,7 +18085,7 @@ void Ifc4x3_rc3::IfcMaterialRelationship::setRelatingMaterial(::Ifc4x3_rc3::IfcM
 aggregate_of< ::Ifc4x3_rc3::IfcMaterial >::ptr Ifc4x3_rc3::IfcMaterialRelationship::RelatedMaterials() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc3::IfcMaterial >(); }
 void Ifc4x3_rc3::IfcMaterialRelationship::setRelatedMaterials(aggregate_of< ::Ifc4x3_rc3::IfcMaterial >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMaterialRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMaterialRelationship::declaration() const { return *IFC4X3_RC3_IfcMaterialRelationship_type; }
@@ -18116,11 +18116,11 @@ Ifc4x3_rc3::IfcMeasureWithUnit::IfcMeasureWithUnit(::Ifc4x3_rc3::IfcValue* v1_Va
 
 // Function implementations for IfcMechanicalFastener
 boost::optional< double > Ifc4x3_rc3::IfcMechanicalFastener::NominalDiameter() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMechanicalFastener::NominalLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcMechanicalFastenerTypeEnum::Value > Ifc4x3_rc3::IfcMechanicalFastener::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMechanicalFastenerTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMechanicalFastenerTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMechanicalFastener::declaration() const { return *IFC4X3_RC3_IfcMechanicalFastener_type; }
@@ -18132,9 +18132,9 @@ Ifc4x3_rc3::IfcMechanicalFastener::IfcMechanicalFastener(std::string v1_GlobalId
 ::Ifc4x3_rc3::IfcMechanicalFastenerTypeEnum::Value Ifc4x3_rc3::IfcMechanicalFastenerType::PredefinedType() const {  return ::Ifc4x3_rc3::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc3::IfcMechanicalFastenerType::setPredefinedType(::Ifc4x3_rc3::IfcMechanicalFastenerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcMechanicalFastenerTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMechanicalFastenerType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcMechanicalFastenerType::NominalLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMechanicalFastenerType::declaration() const { return *IFC4X3_RC3_IfcMechanicalFastenerType_type; }
@@ -18144,7 +18144,7 @@ Ifc4x3_rc3::IfcMechanicalFastenerType::IfcMechanicalFastenerType(std::string v1_
 
 // Function implementations for IfcMedicalDevice
 boost::optional< ::Ifc4x3_rc3::IfcMedicalDeviceTypeEnum::Value > Ifc4x3_rc3::IfcMedicalDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcMedicalDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMedicalDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMedicalDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMedicalDevice::declaration() const { return *IFC4X3_RC3_IfcMedicalDevice_type; }
@@ -18164,7 +18164,7 @@ Ifc4x3_rc3::IfcMedicalDeviceType::IfcMedicalDeviceType(std::string v1_GlobalId,
 
 // Function implementations for IfcMember
 boost::optional< ::Ifc4x3_rc3::IfcMemberTypeEnum::Value > Ifc4x3_rc3::IfcMember::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcMemberTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcMember::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMemberTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcMember::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMemberTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMember::declaration() const { return *IFC4X3_RC3_IfcMember_type; }
@@ -18194,7 +18194,7 @@ Ifc4x3_rc3::IfcMemberType::IfcMemberType(std::string v1_GlobalId, ::Ifc4x3_rc3::
 ::Ifc4x3_rc3::IfcBenchmarkEnum::Value Ifc4x3_rc3::IfcMetric::Benchmark() const {  return ::Ifc4x3_rc3::IfcBenchmarkEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc3::IfcMetric::setBenchmark(::Ifc4x3_rc3::IfcBenchmarkEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcBenchmarkEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcMetric::ValueSource() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc3::IfcMetricValueSelect* Ifc4x3_rc3::IfcMetric::DataValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc3::IfcMetricValueSelect>(true); }
 void Ifc4x3_rc3::IfcMetric::setDataValue(::Ifc4x3_rc3::IfcMetricValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x3_rc3::IfcReference* Ifc4x3_rc3::IfcMetric::ReferencePath() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc3::IfcReference>(true); }
@@ -18216,7 +18216,7 @@ Ifc4x3_rc3::IfcMirroredProfileDef::IfcMirroredProfileDef(::Ifc4x3_rc3::IfcProfil
 
 // Function implementations for IfcMobileTelecommunicationsAppliance
 boost::optional< ::Ifc4x3_rc3::IfcMobileTelecommunicationsApplianceTypeEnum::Value > Ifc4x3_rc3::IfcMobileTelecommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcMobileTelecommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcMobileTelecommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMobileTelecommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMobileTelecommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcMobileTelecommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMobileTelecommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMobileTelecommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMobileTelecommunicationsAppliance::declaration() const { return *IFC4X3_RC3_IfcMobileTelecommunicationsAppliance_type; }
@@ -18246,7 +18246,7 @@ Ifc4x3_rc3::IfcMonetaryUnit::IfcMonetaryUnit(std::string v1_Currency) : IfcUtil:
 
 // Function implementations for IfcMooringDevice
 boost::optional< ::Ifc4x3_rc3::IfcMooringDeviceTypeEnum::Value > Ifc4x3_rc3::IfcMooringDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcMooringDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcMooringDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMooringDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMooringDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcMooringDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMooringDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMooringDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMooringDevice::declaration() const { return *IFC4X3_RC3_IfcMooringDevice_type; }
@@ -18266,7 +18266,7 @@ Ifc4x3_rc3::IfcMooringDeviceType::IfcMooringDeviceType(std::string v1_GlobalId,
 
 // Function implementations for IfcMotorConnection
 boost::optional< ::Ifc4x3_rc3::IfcMotorConnectionTypeEnum::Value > Ifc4x3_rc3::IfcMotorConnection::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcMotorConnectionTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMotorConnectionTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcMotorConnectionTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcMotorConnection::declaration() const { return *IFC4X3_RC3_IfcMotorConnection_type; }
@@ -18298,7 +18298,7 @@ Ifc4x3_rc3::IfcNamedUnit::IfcNamedUnit(::Ifc4x3_rc3::IfcDimensionalExponents* v1
 
 // Function implementations for IfcNavigationElement
 boost::optional< ::Ifc4x3_rc3::IfcNavigationElementTypeEnum::Value > Ifc4x3_rc3::IfcNavigationElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcNavigationElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcNavigationElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcNavigationElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcNavigationElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcNavigationElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcNavigationElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcNavigationElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcNavigationElement::declaration() const { return *IFC4X3_RC3_IfcNavigationElement_type; }
@@ -18318,7 +18318,7 @@ Ifc4x3_rc3::IfcNavigationElementType::IfcNavigationElementType(std::string v1_Gl
 
 // Function implementations for IfcObject
 boost::optional< std::string > Ifc4x3_rc3::IfcObject::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc3::IfcRelDefinesByObject::list::ptr Ifc4x3_rc3::IfcObject::IsDeclaredBy() const { return data_->getInverse(IFC4X3_RC3_IfcRelDefinesByObject_type, 4)->as<IfcRelDefinesByObject>(); }
 ::Ifc4x3_rc3::IfcRelDefinesByObject::list::ptr Ifc4x3_rc3::IfcObject::Declares() const { return data_->getInverse(IFC4X3_RC3_IfcRelDefinesByObject_type, 5)->as<IfcRelDefinesByObject>(); }
@@ -18358,13 +18358,13 @@ Ifc4x3_rc3::IfcObjectPlacement::IfcObjectPlacement(::Ifc4x3_rc3::IfcObjectPlacem
 
 // Function implementations for IfcObjective
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcConstraint >::ptr > Ifc4x3_rc3::IfcObjective::BenchmarkValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc3::IfcConstraint >(); }
-void Ifc4x3_rc3::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcLogicalOperatorEnum::Value > Ifc4x3_rc3::IfcObjective::LogicalAggregator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcLogicalOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x3_rc3::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcLogicalOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x3_rc3::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcLogicalOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc3::IfcObjectiveEnum::Value Ifc4x3_rc3::IfcObjective::ObjectiveQualifier() const {  return ::Ifc4x3_rc3::IfcObjectiveEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc3::IfcObjective::setObjectiveQualifier(::Ifc4x3_rc3::IfcObjectiveEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcObjectiveEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcObjective::UserDefinedQualifier() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcObjective::declaration() const { return *IFC4X3_RC3_IfcObjective_type; }
@@ -18374,7 +18374,7 @@ Ifc4x3_rc3::IfcObjective::IfcObjective(std::string v1_Name, boost::optional< std
 
 // Function implementations for IfcOccupant
 boost::optional< ::Ifc4x3_rc3::IfcOccupantTypeEnum::Value > Ifc4x3_rc3::IfcOccupant::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcOccupantTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc3::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcOccupantTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcOccupantTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcOccupant::declaration() const { return *IFC4X3_RC3_IfcOccupant_type; }
@@ -18422,7 +18422,7 @@ Ifc4x3_rc3::IfcOffsetCurve3D::IfcOffsetCurve3D(::Ifc4x3_rc3::IfcCurve* v1_BasisC
 aggregate_of< ::Ifc4x3_rc3::IfcPointByDistanceExpression >::ptr Ifc4x3_rc3::IfcOffsetCurveByDistances::OffsetValues() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc3::IfcPointByDistanceExpression >(); }
 void Ifc4x3_rc3::IfcOffsetCurveByDistances::setOffsetValues(aggregate_of< ::Ifc4x3_rc3::IfcPointByDistanceExpression >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcOffsetCurveByDistances::Tag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcOffsetCurveByDistances::declaration() const { return *IFC4X3_RC3_IfcOffsetCurveByDistances_type; }
@@ -18438,7 +18438,7 @@ void Ifc4x3_rc3::IfcOpenCrossProfileDef::setWidths(std::vector< double > /*[1:?]
 std::vector< double > /*[1:?]*/ Ifc4x3_rc3::IfcOpenCrossProfileDef::Slopes() const {  std::vector< double > /*[1:?]*/ v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc3::IfcOpenCrossProfileDef::setSlopes(std::vector< double > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[2:?]*/ > Ifc4x3_rc3::IfcOpenCrossProfileDef::Tags() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[2:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcOpenCrossProfileDef::setTags(boost::optional< std::vector< std::string > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcOpenCrossProfileDef::setTags(boost::optional< std::vector< std::string > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcOpenCrossProfileDef::declaration() const { return *IFC4X3_RC3_IfcOpenCrossProfileDef_type; }
@@ -18456,7 +18456,7 @@ Ifc4x3_rc3::IfcOpenShell::IfcOpenShell(aggregate_of< ::Ifc4x3_rc3::IfcFace >::pt
 
 // Function implementations for IfcOpeningElement
 boost::optional< ::Ifc4x3_rc3::IfcOpeningElementTypeEnum::Value > Ifc4x3_rc3::IfcOpeningElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcOpeningElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcOpeningElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcOpeningElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc3::IfcRelFillsElement::list::ptr Ifc4x3_rc3::IfcOpeningElement::HasFillings() const { return data_->getInverse(IFC4X3_RC3_IfcRelFillsElement_type, 4)->as<IfcRelFillsElement>(); }
 
@@ -18475,15 +18475,15 @@ Ifc4x3_rc3::IfcOpeningStandardCase::IfcOpeningStandardCase(std::string v1_Global
 
 // Function implementations for IfcOrganization
 boost::optional< std::string > Ifc4x3_rc3::IfcOrganization::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 std::string Ifc4x3_rc3::IfcOrganization::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcOrganization::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcOrganization::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcActorRole >::ptr > Ifc4x3_rc3::IfcOrganization::Roles() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc3::IfcActorRole >(); }
-void Ifc4x3_rc3::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(3,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAddress >::ptr > Ifc4x3_rc3::IfcOrganization::Addresses() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x3_rc3::IfcAddress >(); }
-void Ifc4x3_rc3::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc3::IfcOrganizationRelationship::list::ptr Ifc4x3_rc3::IfcOrganization::IsRelatedBy() const { return data_->getInverse(IFC4X3_RC3_IfcOrganizationRelationship_type, 3)->as<IfcOrganizationRelationship>(); }
 ::Ifc4x3_rc3::IfcOrganizationRelationship::list::ptr Ifc4x3_rc3::IfcOrganization::Relates() const { return data_->getInverse(IFC4X3_RC3_IfcOrganizationRelationship_type, 2)->as<IfcOrganizationRelationship>(); }
@@ -18528,7 +18528,7 @@ Ifc4x3_rc3::IfcOuterBoundaryCurve::IfcOuterBoundaryCurve(aggregate_of< ::Ifc4x3_
 
 // Function implementations for IfcOutlet
 boost::optional< ::Ifc4x3_rc3::IfcOutletTypeEnum::Value > Ifc4x3_rc3::IfcOutlet::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcOutletTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcOutletTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcOutletTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcOutlet::declaration() const { return *IFC4X3_RC3_IfcOutlet_type; }
@@ -18552,11 +18552,11 @@ void Ifc4x3_rc3::IfcOwnerHistory::setOwningUser(::Ifc4x3_rc3::IfcPersonAndOrgani
 ::Ifc4x3_rc3::IfcApplication* Ifc4x3_rc3::IfcOwnerHistory::OwningApplication() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc3::IfcApplication>(true); }
 void Ifc4x3_rc3::IfcOwnerHistory::setOwningApplication(::Ifc4x3_rc3::IfcApplication* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcStateEnum::Value > Ifc4x3_rc3::IfcOwnerHistory::State() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcStateEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc3::IfcOwnerHistory::setState(boost::optional< ::Ifc4x3_rc3::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcStateEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcOwnerHistory::setState(boost::optional< ::Ifc4x3_rc3::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcStateEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcChangeActionEnum::Value > Ifc4x3_rc3::IfcOwnerHistory::ChangeAction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcChangeActionEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x3_rc3::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x3_rc3::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcChangeActionEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x3_rc3::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcChangeActionEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc3::IfcOwnerHistory::LastModifiedDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc3::IfcPersonAndOrganization* Ifc4x3_rc3::IfcOwnerHistory::LastModifyingUser() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc3::IfcPersonAndOrganization>(true); }
 void Ifc4x3_rc3::IfcOwnerHistory::setLastModifyingUser(::Ifc4x3_rc3::IfcPersonAndOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x3_rc3::IfcApplication* Ifc4x3_rc3::IfcOwnerHistory::LastModifyingApplication() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcApplication>(true); }
@@ -18592,7 +18592,7 @@ Ifc4x3_rc3::IfcPath::IfcPath(aggregate_of< ::Ifc4x3_rc3::IfcOrientedEdge >::ptr
 
 // Function implementations for IfcPavement
 boost::optional< ::Ifc4x3_rc3::IfcPavementTypeEnum::Value > Ifc4x3_rc3::IfcPavement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcPavementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcPavement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPavementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPavementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcPavement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPavementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPavementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPavement::declaration() const { return *IFC4X3_RC3_IfcPavement_type; }
@@ -18626,7 +18626,7 @@ Ifc4x3_rc3::IfcPcurve::IfcPcurve(::Ifc4x3_rc3::IfcSurface* v1_BasisSurface, ::If
 std::string Ifc4x3_rc3::IfcPerformanceHistory::LifeCyclePhase() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcPerformanceHistory::setLifeCyclePhase(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcPerformanceHistoryTypeEnum::Value > Ifc4x3_rc3::IfcPerformanceHistory::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcPerformanceHistoryTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc3::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPerformanceHistoryTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPerformanceHistoryTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPerformanceHistory::declaration() const { return *IFC4X3_RC3_IfcPerformanceHistory_type; }
@@ -18640,9 +18640,9 @@ void Ifc4x3_rc3::IfcPermeableCoveringProperties::setOperationType(::Ifc4x3_rc3::
 ::Ifc4x3_rc3::IfcWindowPanelPositionEnum::Value Ifc4x3_rc3::IfcPermeableCoveringProperties::PanelPosition() const {  return ::Ifc4x3_rc3::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc3::IfcPermeableCoveringProperties::setPanelPosition(::Ifc4x3_rc3::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcPermeableCoveringProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcPermeableCoveringProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcShapeAspect* Ifc4x3_rc3::IfcPermeableCoveringProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc3::IfcShapeAspect>(true); }
 void Ifc4x3_rc3::IfcPermeableCoveringProperties::setShapeAspectStyle(::Ifc4x3_rc3::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -18654,11 +18654,11 @@ Ifc4x3_rc3::IfcPermeableCoveringProperties::IfcPermeableCoveringProperties(std::
 
 // Function implementations for IfcPermit
 boost::optional< ::Ifc4x3_rc3::IfcPermitTypeEnum::Value > Ifc4x3_rc3::IfcPermit::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcPermitTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc3::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPermitTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPermitTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPermit::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPermit::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPermit::declaration() const { return *IFC4X3_RC3_IfcPermit_type; }
@@ -18668,21 +18668,21 @@ Ifc4x3_rc3::IfcPermit::IfcPermit(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwner
 
 // Function implementations for IfcPerson
 boost::optional< std::string > Ifc4x3_rc3::IfcPerson::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPerson::FamilyName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPerson::GivenName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcPerson::MiddleNames() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcPerson::PrefixTitles() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcPerson::SuffixTitles() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcActorRole >::ptr > Ifc4x3_rc3::IfcPerson::Roles() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc3::IfcActorRole >(); }
-void Ifc4x3_rc3::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAddress >::ptr > Ifc4x3_rc3::IfcPerson::Addresses() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc3::IfcAddress >(); }
-void Ifc4x3_rc3::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc3::IfcPersonAndOrganization::list::ptr Ifc4x3_rc3::IfcPerson::EngagedIn() const { return data_->getInverse(IFC4X3_RC3_IfcPersonAndOrganization_type, 0)->as<IfcPersonAndOrganization>(); }
 
@@ -18697,7 +18697,7 @@ void Ifc4x3_rc3::IfcPersonAndOrganization::setThePerson(::Ifc4x3_rc3::IfcPerson*
 ::Ifc4x3_rc3::IfcOrganization* Ifc4x3_rc3::IfcPersonAndOrganization::TheOrganization() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc3::IfcOrganization>(true); }
 void Ifc4x3_rc3::IfcPersonAndOrganization::setTheOrganization(::Ifc4x3_rc3::IfcOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcActorRole >::ptr > Ifc4x3_rc3::IfcPersonAndOrganization::Roles() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc3::IfcActorRole >(); }
-void Ifc4x3_rc3::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPersonAndOrganization::declaration() const { return *IFC4X3_RC3_IfcPersonAndOrganization_type; }
@@ -18711,9 +18711,9 @@ void Ifc4x3_rc3::IfcPhysicalComplexQuantity::setHasQuantities(aggregate_of< ::If
 std::string Ifc4x3_rc3::IfcPhysicalComplexQuantity::Discrimination() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcPhysicalComplexQuantity::setDiscrimination(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPhysicalComplexQuantity::Quality() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPhysicalComplexQuantity::Usage() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPhysicalComplexQuantity::declaration() const { return *IFC4X3_RC3_IfcPhysicalComplexQuantity_type; }
@@ -18725,7 +18725,7 @@ Ifc4x3_rc3::IfcPhysicalComplexQuantity::IfcPhysicalComplexQuantity(std::string v
 std::string Ifc4x3_rc3::IfcPhysicalQuantity::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc3::IfcPhysicalQuantity::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPhysicalQuantity::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc3::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc3::IfcPhysicalQuantity::HasExternalReferences() const { return data_->getInverse(IFC4X3_RC3_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc3::IfcPhysicalComplexQuantity::list::ptr Ifc4x3_rc3::IfcPhysicalQuantity::PartOfComplex() const { return data_->getInverse(IFC4X3_RC3_IfcPhysicalComplexQuantity_type, 2)->as<IfcPhysicalComplexQuantity>(); }
@@ -18747,9 +18747,9 @@ Ifc4x3_rc3::IfcPhysicalSimpleQuantity::IfcPhysicalSimpleQuantity(std::string v1_
 
 // Function implementations for IfcPile
 boost::optional< ::Ifc4x3_rc3::IfcPileTypeEnum::Value > Ifc4x3_rc3::IfcPile::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcPileTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcPile::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPileTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcPile::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPileTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcPileConstructionEnum::Value > Ifc4x3_rc3::IfcPile::ConstructionType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcPileConstructionEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcPile::setConstructionType(boost::optional< ::Ifc4x3_rc3::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPileConstructionEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcPile::setConstructionType(boost::optional< ::Ifc4x3_rc3::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPileConstructionEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPile::declaration() const { return *IFC4X3_RC3_IfcPile_type; }
@@ -18769,7 +18769,7 @@ Ifc4x3_rc3::IfcPileType::IfcPileType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcPipeFitting
 boost::optional< ::Ifc4x3_rc3::IfcPipeFittingTypeEnum::Value > Ifc4x3_rc3::IfcPipeFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcPipeFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPipeFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPipeFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPipeFitting::declaration() const { return *IFC4X3_RC3_IfcPipeFitting_type; }
@@ -18789,7 +18789,7 @@ Ifc4x3_rc3::IfcPipeFittingType::IfcPipeFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcPipeSegment
 boost::optional< ::Ifc4x3_rc3::IfcPipeSegmentTypeEnum::Value > Ifc4x3_rc3::IfcPipeSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcPipeSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPipeSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPipeSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPipeSegment::declaration() const { return *IFC4X3_RC3_IfcPipeSegment_type; }
@@ -18873,7 +18873,7 @@ Ifc4x3_rc3::IfcPlant::IfcPlant(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHi
 
 // Function implementations for IfcPlate
 boost::optional< ::Ifc4x3_rc3::IfcPlateTypeEnum::Value > Ifc4x3_rc3::IfcPlate::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcPlateTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPlateTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPlateTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPlate::declaration() const { return *IFC4X3_RC3_IfcPlate_type; }
@@ -18911,11 +18911,11 @@ Ifc4x3_rc3::IfcPoint::IfcPoint() : IfcGeometricRepresentationItem((IfcEntityInst
 ::Ifc4x3_rc3::IfcCurveMeasureSelect* Ifc4x3_rc3::IfcPointByDistanceExpression::DistanceAlong() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc3::IfcCurveMeasureSelect>(true); }
 void Ifc4x3_rc3::IfcPointByDistanceExpression::setDistanceAlong(::Ifc4x3_rc3::IfcCurveMeasureSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcPointByDistanceExpression::OffsetLateral() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcPointByDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcPointByDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcPointByDistanceExpression::OffsetVertical() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcPointByDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcPointByDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcPointByDistanceExpression::OffsetLongitudinal() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcPointByDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcPointByDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc3::IfcCurve* Ifc4x3_rc3::IfcPointByDistanceExpression::BasisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc3::IfcCurve>(true); }
 void Ifc4x3_rc3::IfcPointByDistanceExpression::setBasisCurve(::Ifc4x3_rc3::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -18975,11 +18975,11 @@ Ifc4x3_rc3::IfcPolygonalBoundedHalfSpace::IfcPolygonalBoundedHalfSpace(::Ifc4x3_
 
 // Function implementations for IfcPolygonalFaceSet
 boost::optional< bool > Ifc4x3_rc3::IfcPolygonalFaceSet::Closed() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc3::IfcIndexedPolygonalFace >::ptr Ifc4x3_rc3::IfcPolygonalFaceSet::Faces() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc3::IfcIndexedPolygonalFace >(); }
 void Ifc4x3_rc3::IfcPolygonalFaceSet::setFaces(aggregate_of< ::Ifc4x3_rc3::IfcIndexedPolygonalFace >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc3::IfcPolygonalFaceSet::PnIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPolygonalFaceSet::declaration() const { return *IFC4X3_RC3_IfcPolygonalFaceSet_type; }
@@ -19001,11 +19001,11 @@ Ifc4x3_rc3::IfcPolyline::IfcPolyline(aggregate_of< ::Ifc4x3_rc3::IfcCartesianPoi
 ::Ifc4x3_rc3::IfcPlacement* Ifc4x3_rc3::IfcPolynomialCurve::Position() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc3::IfcPlacement>(true); }
 void Ifc4x3_rc3::IfcPolynomialCurve::setPosition(::Ifc4x3_rc3::IfcPlacement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< double > /*[2:?]*/ > Ifc4x3_rc3::IfcPolynomialCurve::CoefficientsX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< double > /*[2:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcPolynomialCurve::setCoefficientsX(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcPolynomialCurve::setCoefficientsX(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[2:?]*/ > Ifc4x3_rc3::IfcPolynomialCurve::CoefficientsY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[2:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcPolynomialCurve::setCoefficientsY(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcPolynomialCurve::setCoefficientsY(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< double > /*[2:?]*/ > Ifc4x3_rc3::IfcPolynomialCurve::CoefficientsZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< double > /*[2:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcPolynomialCurve::setCoefficientsZ(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcPolynomialCurve::setCoefficientsZ(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPolynomialCurve::declaration() const { return *IFC4X3_RC3_IfcPolynomialCurve_type; }
@@ -19036,19 +19036,19 @@ Ifc4x3_rc3::IfcPositioningElement::IfcPositioningElement(std::string v1_GlobalId
 
 // Function implementations for IfcPostalAddress
 boost::optional< std::string > Ifc4x3_rc3::IfcPostalAddress::InternalLocation() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcPostalAddress::AddressLines() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPostalAddress::PostalBox() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPostalAddress::Town() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPostalAddress::Region() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPostalAddress::PostalCode() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPostalAddress::Country() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPostalAddress::declaration() const { return *IFC4X3_RC3_IfcPostalAddress_type; }
@@ -19118,11 +19118,11 @@ Ifc4x3_rc3::IfcPresentationItem::IfcPresentationItem() : IfcUtil::IfcBaseEntity(
 std::string Ifc4x3_rc3::IfcPresentationLayerAssignment::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc3::IfcPresentationLayerAssignment::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPresentationLayerAssignment::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of_instance::ptr Ifc4x3_rc3::IfcPresentationLayerAssignment::AssignedItems() const {  aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc3::IfcPresentationLayerAssignment::setAssignedItems(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPresentationLayerAssignment::Identifier() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPresentationLayerAssignment::declaration() const { return *IFC4X3_RC3_IfcPresentationLayerAssignment_type; }
@@ -19148,7 +19148,7 @@ Ifc4x3_rc3::IfcPresentationLayerWithStyle::IfcPresentationLayerWithStyle(std::st
 
 // Function implementations for IfcPresentationStyle
 boost::optional< std::string > Ifc4x3_rc3::IfcPresentationStyle::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPresentationStyle::declaration() const { return *IFC4X3_RC3_IfcPresentationStyle_type; }
@@ -19158,7 +19158,7 @@ Ifc4x3_rc3::IfcPresentationStyle::IfcPresentationStyle(boost::optional< std::str
 
 // Function implementations for IfcProcedure
 boost::optional< ::Ifc4x3_rc3::IfcProcedureTypeEnum::Value > Ifc4x3_rc3::IfcProcedure::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcProcedureTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc3::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProcedureTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProcedureTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcProcedure::declaration() const { return *IFC4X3_RC3_IfcProcedure_type; }
@@ -19178,9 +19178,9 @@ Ifc4x3_rc3::IfcProcedureType::IfcProcedureType(std::string v1_GlobalId, ::Ifc4x3
 
 // Function implementations for IfcProcess
 boost::optional< std::string > Ifc4x3_rc3::IfcProcess::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcProcess::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc3::IfcRelSequence::list::ptr Ifc4x3_rc3::IfcProcess::IsPredecessorTo() const { return data_->getInverse(IFC4X3_RC3_IfcRelSequence_type, 4)->as<IfcRelSequence>(); }
 ::Ifc4x3_rc3::IfcRelSequence::list::ptr Ifc4x3_rc3::IfcProcess::IsSuccessorFrom() const { return data_->getInverse(IFC4X3_RC3_IfcRelSequence_type, 5)->as<IfcRelSequence>(); }
@@ -19218,9 +19218,9 @@ Ifc4x3_rc3::IfcProductDefinitionShape::IfcProductDefinitionShape(boost::optional
 
 // Function implementations for IfcProductRepresentation
 boost::optional< std::string > Ifc4x3_rc3::IfcProductRepresentation::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcProductRepresentation::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc3::IfcRepresentation >::ptr Ifc4x3_rc3::IfcProductRepresentation::Representations() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc3::IfcRepresentation >(); }
 void Ifc4x3_rc3::IfcProductRepresentation::setRepresentations(aggregate_of< ::Ifc4x3_rc3::IfcRepresentation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -19234,7 +19234,7 @@ Ifc4x3_rc3::IfcProductRepresentation::IfcProductRepresentation(boost::optional<
 ::Ifc4x3_rc3::IfcProfileTypeEnum::Value Ifc4x3_rc3::IfcProfileDef::ProfileType() const {  return ::Ifc4x3_rc3::IfcProfileTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc3::IfcProfileDef::setProfileType(::Ifc4x3_rc3::IfcProfileTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcProfileTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcProfileDef::ProfileName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc3::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc3::IfcProfileDef::HasExternalReference() const { return data_->getInverse(IFC4X3_RC3_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc3::IfcProfileProperties::list::ptr Ifc4x3_rc3::IfcProfileDef::HasProperties() const { return data_->getInverse(IFC4X3_RC3_IfcProfileProperties_type, 3)->as<IfcProfileProperties>(); }
@@ -19272,11 +19272,11 @@ Ifc4x3_rc3::IfcProjectLibrary::IfcProjectLibrary(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcProjectOrder
 boost::optional< ::Ifc4x3_rc3::IfcProjectOrderTypeEnum::Value > Ifc4x3_rc3::IfcProjectOrder::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcProjectOrderTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc3::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProjectOrderTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProjectOrderTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcProjectOrder::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcProjectOrder::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcProjectOrder::declaration() const { return *IFC4X3_RC3_IfcProjectOrder_type; }
@@ -19286,9 +19286,9 @@ Ifc4x3_rc3::IfcProjectOrder::IfcProjectOrder(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcProjectedCRS
 boost::optional< std::string > Ifc4x3_rc3::IfcProjectedCRS::MapProjection() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcProjectedCRS::MapZone() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc3::IfcNamedUnit* Ifc4x3_rc3::IfcProjectedCRS::MapUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcNamedUnit>(true); }
 void Ifc4x3_rc3::IfcProjectedCRS::setMapUnit(::Ifc4x3_rc3::IfcNamedUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -19300,7 +19300,7 @@ Ifc4x3_rc3::IfcProjectedCRS::IfcProjectedCRS(std::string v1_Name, boost::optiona
 
 // Function implementations for IfcProjectionElement
 boost::optional< ::Ifc4x3_rc3::IfcProjectionElementTypeEnum::Value > Ifc4x3_rc3::IfcProjectionElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcProjectionElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProjectionElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProjectionElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcProjectionElement::declaration() const { return *IFC4X3_RC3_IfcProjectionElement_type; }
@@ -19312,7 +19312,7 @@ Ifc4x3_rc3::IfcProjectionElement::IfcProjectionElement(std::string v1_GlobalId,
 std::string Ifc4x3_rc3::IfcProperty::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc3::IfcProperty::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcProperty::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc3::IfcPropertySet::list::ptr Ifc4x3_rc3::IfcProperty::PartOfPset() const { return data_->getInverse(IFC4X3_RC3_IfcPropertySet_type, 4)->as<IfcPropertySet>(); }
 ::Ifc4x3_rc3::IfcPropertyDependencyRelationship::list::ptr Ifc4x3_rc3::IfcProperty::PropertyForDependance() const { return data_->getInverse(IFC4X3_RC3_IfcPropertyDependencyRelationship_type, 2)->as<IfcPropertyDependencyRelationship>(); }
@@ -19367,7 +19367,7 @@ void Ifc4x3_rc3::IfcPropertyDependencyRelationship::setDependingProperty(::Ifc4x
 ::Ifc4x3_rc3::IfcProperty* Ifc4x3_rc3::IfcPropertyDependencyRelationship::DependantProperty() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcProperty>(true); }
 void Ifc4x3_rc3::IfcPropertyDependencyRelationship::setDependantProperty(::Ifc4x3_rc3::IfcProperty* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPropertyDependencyRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPropertyDependencyRelationship::declaration() const { return *IFC4X3_RC3_IfcPropertyDependencyRelationship_type; }
@@ -19377,7 +19377,7 @@ Ifc4x3_rc3::IfcPropertyDependencyRelationship::IfcPropertyDependencyRelationship
 
 // Function implementations for IfcPropertyEnumeratedValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc3::IfcPropertyEnumeratedValue::EnumerationValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcPropertyEnumeration* Ifc4x3_rc3::IfcPropertyEnumeratedValue::EnumerationReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcPropertyEnumeration>(true); }
 void Ifc4x3_rc3::IfcPropertyEnumeratedValue::setEnumerationReference(::Ifc4x3_rc3::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19403,7 +19403,7 @@ Ifc4x3_rc3::IfcPropertyEnumeration::IfcPropertyEnumeration(std::string v1_Name,
 
 // Function implementations for IfcPropertyListValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc3::IfcPropertyListValue::ListValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcUnit* Ifc4x3_rc3::IfcPropertyListValue::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcUnit>(true); }
 void Ifc4x3_rc3::IfcPropertyListValue::setUnit(::Ifc4x3_rc3::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19415,7 +19415,7 @@ Ifc4x3_rc3::IfcPropertyListValue::IfcPropertyListValue(std::string v1_Name, boos
 
 // Function implementations for IfcPropertyReferenceValue
 boost::optional< std::string > Ifc4x3_rc3::IfcPropertyReferenceValue::UsageName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcObjectReferenceSelect* Ifc4x3_rc3::IfcPropertyReferenceValue::PropertyReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcObjectReferenceSelect>(true); }
 void Ifc4x3_rc3::IfcPropertyReferenceValue::setPropertyReference(::Ifc4x3_rc3::IfcObjectReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19448,9 +19448,9 @@ Ifc4x3_rc3::IfcPropertySetDefinition::IfcPropertySetDefinition(std::string v1_Gl
 
 // Function implementations for IfcPropertySetTemplate
 boost::optional< ::Ifc4x3_rc3::IfcPropertySetTemplateTypeEnum::Value > Ifc4x3_rc3::IfcPropertySetTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcPropertySetTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x3_rc3::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc3::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPropertySetTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc3::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPropertySetTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPropertySetTemplate::ApplicableEntity() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 aggregate_of< ::Ifc4x3_rc3::IfcPropertyTemplate >::ptr Ifc4x3_rc3::IfcPropertySetTemplate::HasPropertyTemplates() const {  aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc3::IfcPropertyTemplate >(); }
 void Ifc4x3_rc3::IfcPropertySetTemplate::setHasPropertyTemplates(aggregate_of< ::Ifc4x3_rc3::IfcPropertyTemplate >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(6,attr);} }
 
@@ -19475,17 +19475,17 @@ Ifc4x3_rc3::IfcPropertySingleValue::IfcPropertySingleValue(std::string v1_Name,
 
 // Function implementations for IfcPropertyTableValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc3::IfcPropertyTableValue::DefiningValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc3::IfcPropertyTableValue::DefinedValues() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcPropertyTableValue::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc3::IfcUnit* Ifc4x3_rc3::IfcPropertyTableValue::DefiningUnit() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc3::IfcUnit>(true); }
 void Ifc4x3_rc3::IfcPropertyTableValue::setDefiningUnit(::Ifc4x3_rc3::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x3_rc3::IfcUnit* Ifc4x3_rc3::IfcPropertyTableValue::DefinedUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcUnit>(true); }
 void Ifc4x3_rc3::IfcPropertyTableValue::setDefinedUnit(::Ifc4x3_rc3::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcCurveInterpolationEnum::Value > Ifc4x3_rc3::IfcPropertyTableValue::CurveInterpolation() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcCurveInterpolationEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc3::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x3_rc3::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCurveInterpolationEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x3_rc3::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcCurveInterpolationEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPropertyTableValue::declaration() const { return *IFC4X3_RC3_IfcPropertyTableValue_type; }
@@ -19513,7 +19513,7 @@ Ifc4x3_rc3::IfcPropertyTemplateDefinition::IfcPropertyTemplateDefinition(std::st
 
 // Function implementations for IfcProtectiveDevice
 boost::optional< ::Ifc4x3_rc3::IfcProtectiveDeviceTypeEnum::Value > Ifc4x3_rc3::IfcProtectiveDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcProtectiveDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProtectiveDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProtectiveDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcProtectiveDevice::declaration() const { return *IFC4X3_RC3_IfcProtectiveDevice_type; }
@@ -19523,7 +19523,7 @@ Ifc4x3_rc3::IfcProtectiveDevice::IfcProtectiveDevice(std::string v1_GlobalId, ::
 
 // Function implementations for IfcProtectiveDeviceTrippingUnit
 boost::optional< ::Ifc4x3_rc3::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > Ifc4x3_rc3::IfcProtectiveDeviceTrippingUnit::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcProtectiveDeviceTrippingUnitTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcProtectiveDeviceTrippingUnit::declaration() const { return *IFC4X3_RC3_IfcProtectiveDeviceTrippingUnit_type; }
@@ -19555,7 +19555,7 @@ Ifc4x3_rc3::IfcProtectiveDeviceType::IfcProtectiveDeviceType(std::string v1_Glob
 ::Ifc4x3_rc3::IfcObjectTypeEnum::Value Ifc4x3_rc3::IfcProxy::ProxyType() const {  return ::Ifc4x3_rc3::IfcObjectTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc3::IfcProxy::setProxyType(::Ifc4x3_rc3::IfcObjectTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcObjectTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcProxy::Tag() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcProxy::declaration() const { return *IFC4X3_RC3_IfcProxy_type; }
@@ -19565,7 +19565,7 @@ Ifc4x3_rc3::IfcProxy::IfcProxy(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHi
 
 // Function implementations for IfcPump
 boost::optional< ::Ifc4x3_rc3::IfcPumpTypeEnum::Value > Ifc4x3_rc3::IfcPump::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcPumpTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcPump::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPumpTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcPump::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcPumpTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcPump::declaration() const { return *IFC4X3_RC3_IfcPump_type; }
@@ -19587,7 +19587,7 @@ Ifc4x3_rc3::IfcPumpType::IfcPumpType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 double Ifc4x3_rc3::IfcQuantityArea::AreaValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcQuantityArea::setAreaValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcQuantityArea::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcQuantityArea::declaration() const { return *IFC4X3_RC3_IfcQuantityArea_type; }
@@ -19599,7 +19599,7 @@ Ifc4x3_rc3::IfcQuantityArea::IfcQuantityArea(std::string v1_Name, boost::optiona
 double Ifc4x3_rc3::IfcQuantityCount::CountValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcQuantityCount::setCountValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcQuantityCount::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcQuantityCount::declaration() const { return *IFC4X3_RC3_IfcQuantityCount_type; }
@@ -19611,7 +19611,7 @@ Ifc4x3_rc3::IfcQuantityCount::IfcQuantityCount(std::string v1_Name, boost::optio
 double Ifc4x3_rc3::IfcQuantityLength::LengthValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcQuantityLength::setLengthValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcQuantityLength::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcQuantityLength::declaration() const { return *IFC4X3_RC3_IfcQuantityLength_type; }
@@ -19631,7 +19631,7 @@ Ifc4x3_rc3::IfcQuantitySet::IfcQuantitySet(std::string v1_GlobalId, ::Ifc4x3_rc3
 double Ifc4x3_rc3::IfcQuantityTime::TimeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcQuantityTime::setTimeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcQuantityTime::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcQuantityTime::declaration() const { return *IFC4X3_RC3_IfcQuantityTime_type; }
@@ -19643,7 +19643,7 @@ Ifc4x3_rc3::IfcQuantityTime::IfcQuantityTime(std::string v1_Name, boost::optiona
 double Ifc4x3_rc3::IfcQuantityVolume::VolumeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcQuantityVolume::setVolumeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcQuantityVolume::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcQuantityVolume::declaration() const { return *IFC4X3_RC3_IfcQuantityVolume_type; }
@@ -19655,7 +19655,7 @@ Ifc4x3_rc3::IfcQuantityVolume::IfcQuantityVolume(std::string v1_Name, boost::opt
 double Ifc4x3_rc3::IfcQuantityWeight::WeightValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcQuantityWeight::setWeightValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcQuantityWeight::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcQuantityWeight::declaration() const { return *IFC4X3_RC3_IfcQuantityWeight_type; }
@@ -19665,7 +19665,7 @@ Ifc4x3_rc3::IfcQuantityWeight::IfcQuantityWeight(std::string v1_Name, boost::opt
 
 // Function implementations for IfcRail
 boost::optional< ::Ifc4x3_rc3::IfcRailTypeEnum::Value > Ifc4x3_rc3::IfcRail::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcRailTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcRail::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRailTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRailTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcRail::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRailTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRailTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRail::declaration() const { return *IFC4X3_RC3_IfcRail_type; }
@@ -19685,7 +19685,7 @@ Ifc4x3_rc3::IfcRailType::IfcRailType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcRailing
 boost::optional< ::Ifc4x3_rc3::IfcRailingTypeEnum::Value > Ifc4x3_rc3::IfcRailing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcRailingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRailingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRailingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRailing::declaration() const { return *IFC4X3_RC3_IfcRailing_type; }
@@ -19705,7 +19705,7 @@ Ifc4x3_rc3::IfcRailingType::IfcRailingType(std::string v1_GlobalId, ::Ifc4x3_rc3
 
 // Function implementations for IfcRailway
 boost::optional< ::Ifc4x3_rc3::IfcRailwayTypeEnum::Value > Ifc4x3_rc3::IfcRailway::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcRailwayTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcRailway::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRailwayTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRailwayTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcRailway::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRailwayTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRailwayTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRailway::declaration() const { return *IFC4X3_RC3_IfcRailway_type; }
@@ -19715,7 +19715,7 @@ Ifc4x3_rc3::IfcRailway::IfcRailway(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwn
 
 // Function implementations for IfcRamp
 boost::optional< ::Ifc4x3_rc3::IfcRampTypeEnum::Value > Ifc4x3_rc3::IfcRamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcRampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRamp::declaration() const { return *IFC4X3_RC3_IfcRamp_type; }
@@ -19725,7 +19725,7 @@ Ifc4x3_rc3::IfcRamp::IfcRamp(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHist
 
 // Function implementations for IfcRampFlight
 boost::optional< ::Ifc4x3_rc3::IfcRampFlightTypeEnum::Value > Ifc4x3_rc3::IfcRampFlight::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcRampFlightTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRampFlightTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRampFlightTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRampFlight::declaration() const { return *IFC4X3_RC3_IfcRampFlight_type; }
@@ -19777,9 +19777,9 @@ Ifc4x3_rc3::IfcRationalBSplineSurfaceWithKnots::IfcRationalBSplineSurfaceWithKno
 double Ifc4x3_rc3::IfcRectangleHollowProfileDef::WallThickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc3::IfcRectangleHollowProfileDef::setWallThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcRectangleHollowProfileDef::InnerFilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcRectangleHollowProfileDef::OuterFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRectangleHollowProfileDef::declaration() const { return *IFC4X3_RC3_IfcRectangleHollowProfileDef_type; }
@@ -19839,19 +19839,19 @@ Ifc4x3_rc3::IfcRectangularTrimmedSurface::IfcRectangularTrimmedSurface(::Ifc4x3_
 ::Ifc4x3_rc3::IfcRecurrenceTypeEnum::Value Ifc4x3_rc3::IfcRecurrencePattern::RecurrenceType() const {  return ::Ifc4x3_rc3::IfcRecurrenceTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc3::IfcRecurrencePattern::setRecurrenceType(::Ifc4x3_rc3::IfcRecurrenceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcRecurrenceTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc3::IfcRecurrencePattern::DayComponent() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc3::IfcRecurrencePattern::WeekdayComponent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc3::IfcRecurrencePattern::MonthComponent() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc3::IfcRecurrencePattern::Position() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< int > Ifc4x3_rc3::IfcRecurrencePattern::Interval() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } int v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x3_rc3::IfcRecurrencePattern::Occurrences() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcTimePeriod >::ptr > Ifc4x3_rc3::IfcRecurrencePattern::TimePeriods() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc3::IfcTimePeriod >(); }
-void Ifc4x3_rc3::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRecurrencePattern::declaration() const { return *IFC4X3_RC3_IfcRecurrencePattern_type; }
@@ -19861,13 +19861,13 @@ Ifc4x3_rc3::IfcRecurrencePattern::IfcRecurrencePattern(::Ifc4x3_rc3::IfcRecurren
 
 // Function implementations for IfcReference
 boost::optional< std::string > Ifc4x3_rc3::IfcReference::TypeIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcReference::AttributeIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcReference::InstanceName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc3::IfcReference::ListPositions() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc3::IfcReference* Ifc4x3_rc3::IfcReference::InnerReference() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc3::IfcReference>(true); }
 void Ifc4x3_rc3::IfcReference::setInnerReference(::Ifc4x3_rc3::IfcReference* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -19879,9 +19879,9 @@ Ifc4x3_rc3::IfcReference::IfcReference(boost::optional< std::string > v1_TypeIde
 
 // Function implementations for IfcReferent
 boost::optional< ::Ifc4x3_rc3::IfcReferentTypeEnum::Value > Ifc4x3_rc3::IfcReferent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcReferentTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc3::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReferentTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReferentTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReferent::RestartDistance() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcReferent::declaration() const { return *IFC4X3_RC3_IfcReferent_type; }
@@ -19903,7 +19903,7 @@ Ifc4x3_rc3::IfcRegularTimeSeries::IfcRegularTimeSeries(std::string v1_Name, boos
 
 // Function implementations for IfcReinforcedSoil
 boost::optional< ::Ifc4x3_rc3::IfcReinforcedSoilTypeEnum::Value > Ifc4x3_rc3::IfcReinforcedSoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcReinforcedSoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcReinforcedSoil::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcReinforcedSoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcedSoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcReinforcedSoil::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcReinforcedSoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcedSoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcReinforcedSoil::declaration() const { return *IFC4X3_RC3_IfcReinforcedSoil_type; }
@@ -19917,13 +19917,13 @@ void Ifc4x3_rc3::IfcReinforcementBarProperties::setTotalCrossSectionArea(double
 std::string Ifc4x3_rc3::IfcReinforcementBarProperties::SteelGrade() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcReinforcementBarProperties::setSteelGrade(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc3::IfcReinforcementBarProperties::BarSurface() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc3::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcementBarProperties::EffectiveDepth() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcementBarProperties::NominalBarDiameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcementBarProperties::BarCount() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcReinforcementBarProperties::declaration() const { return *IFC4X3_RC3_IfcReinforcementBarProperties_type; }
@@ -19933,7 +19933,7 @@ Ifc4x3_rc3::IfcReinforcementBarProperties::IfcReinforcementBarProperties(double
 
 // Function implementations for IfcReinforcementDefinitionProperties
 boost::optional< std::string > Ifc4x3_rc3::IfcReinforcementDefinitionProperties::DefinitionType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x3_rc3::IfcSectionReinforcementProperties >::ptr Ifc4x3_rc3::IfcReinforcementDefinitionProperties::ReinforcementSectionDefinitions() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc3::IfcSectionReinforcementProperties >(); }
 void Ifc4x3_rc3::IfcReinforcementDefinitionProperties::setReinforcementSectionDefinitions(aggregate_of< ::Ifc4x3_rc3::IfcSectionReinforcementProperties >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -19945,15 +19945,15 @@ Ifc4x3_rc3::IfcReinforcementDefinitionProperties::IfcReinforcementDefinitionProp
 
 // Function implementations for IfcReinforcingBar
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingBar::NominalDiameter() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingBar::CrossSectionArea() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingBar::BarLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarTypeEnum::Value > Ifc4x3_rc3::IfcReinforcingBar::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc3::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcingBarTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcingBarTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc3::IfcReinforcingBar::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc3::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcReinforcingBar::declaration() const { return *IFC4X3_RC3_IfcReinforcingBar_type; }
@@ -19965,17 +19965,17 @@ Ifc4x3_rc3::IfcReinforcingBar::IfcReinforcingBar(std::string v1_GlobalId, ::Ifc4
 ::Ifc4x3_rc3::IfcReinforcingBarTypeEnum::Value Ifc4x3_rc3::IfcReinforcingBarType::PredefinedType() const {  return ::Ifc4x3_rc3::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc3::IfcReinforcingBarType::setPredefinedType(::Ifc4x3_rc3::IfcReinforcingBarTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcReinforcingBarTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingBarType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingBarType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingBarType::BarLength() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc3::IfcReinforcingBarType::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc3::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcReinforcingBarType::BendingShapeCode() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc3::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc3::IfcReinforcingBarType::BendingParameters() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc3::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc3::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcReinforcingBarType::declaration() const { return *IFC4X3_RC3_IfcReinforcingBarType_type; }
@@ -19985,7 +19985,7 @@ Ifc4x3_rc3::IfcReinforcingBarType::IfcReinforcingBarType(std::string v1_GlobalId
 
 // Function implementations for IfcReinforcingElement
 boost::optional< std::string > Ifc4x3_rc3::IfcReinforcingElement::SteelGrade() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcReinforcingElement::declaration() const { return *IFC4X3_RC3_IfcReinforcingElement_type; }
@@ -20003,23 +20003,23 @@ Ifc4x3_rc3::IfcReinforcingElementType::IfcReinforcingElementType(std::string v1_
 
 // Function implementations for IfcReinforcingMesh
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMesh::MeshLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMesh::MeshWidth() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMesh::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMesh::TransverseBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMesh::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc3::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMesh::TransverseBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc3::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMesh::LongitudinalBarSpacing() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc3::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMesh::TransverseBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc3::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcReinforcingMeshTypeEnum::Value > Ifc4x3_rc3::IfcReinforcingMesh::PredefinedType() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(17)); }
-void Ifc4x3_rc3::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcingMeshTypeEnum::ToString(*v)));data_->setArgument(17,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcReinforcingMeshTypeEnum::ToString(*v)));}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcReinforcingMesh::declaration() const { return *IFC4X3_RC3_IfcReinforcingMesh_type; }
@@ -20031,25 +20031,25 @@ Ifc4x3_rc3::IfcReinforcingMesh::IfcReinforcingMesh(std::string v1_GlobalId, ::If
 ::Ifc4x3_rc3::IfcReinforcingMeshTypeEnum::Value Ifc4x3_rc3::IfcReinforcingMeshType::PredefinedType() const {  return ::Ifc4x3_rc3::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc3::IfcReinforcingMeshType::setPredefinedType(::Ifc4x3_rc3::IfcReinforcingMeshTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcReinforcingMeshTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMeshType::MeshLength() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMeshType::MeshWidth() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMeshType::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMeshType::TransverseBarNominalDiameter() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc3::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMeshType::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc3::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMeshType::TransverseBarCrossSectionArea() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc3::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMeshType::LongitudinalBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc3::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcReinforcingMeshType::TransverseBarSpacing() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc3::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcReinforcingMeshType::BendingShapeCode() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x3_rc3::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc3::IfcReinforcingMeshType::BendingParameters() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(19); return v; }
-void Ifc4x3_rc3::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x3_rc3::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcReinforcingMeshType::declaration() const { return *IFC4X3_RC3_IfcReinforcingMeshType_type; }
@@ -20073,7 +20073,7 @@ Ifc4x3_rc3::IfcRelAggregates::IfcRelAggregates(std::string v1_GlobalId, ::Ifc4x3
 aggregate_of< ::Ifc4x3_rc3::IfcObjectDefinition >::ptr Ifc4x3_rc3::IfcRelAssigns::RelatedObjects() const {  aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x3_rc3::IfcObjectDefinition >(); }
 void Ifc4x3_rc3::IfcRelAssigns::setRelatedObjects(aggregate_of< ::Ifc4x3_rc3::IfcObjectDefinition >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcObjectTypeEnum::Value > Ifc4x3_rc3::IfcRelAssigns::RelatedObjectsType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcObjectTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc3::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x3_rc3::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcObjectTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x3_rc3::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcObjectTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRelAssigns::declaration() const { return *IFC4X3_RC3_IfcRelAssigns_type; }
@@ -20187,7 +20187,7 @@ Ifc4x3_rc3::IfcRelAssociatesClassification::IfcRelAssociatesClassification(std::
 
 // Function implementations for IfcRelAssociatesConstraint
 boost::optional< std::string > Ifc4x3_rc3::IfcRelAssociatesConstraint::Intent() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc3::IfcConstraint* Ifc4x3_rc3::IfcRelAssociatesConstraint::RelatingConstraint() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcConstraint>(true); }
 void Ifc4x3_rc3::IfcRelAssociatesConstraint::setRelatingConstraint(::Ifc4x3_rc3::IfcConstraint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -20323,7 +20323,7 @@ void Ifc4x3_rc3::IfcRelConnectsStructuralMember::setAppliedCondition(::Ifc4x3_rc
 ::Ifc4x3_rc3::IfcStructuralConnectionCondition* Ifc4x3_rc3::IfcRelConnectsStructuralMember::AdditionalConditions() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc3::IfcStructuralConnectionCondition>(true); }
 void Ifc4x3_rc3::IfcRelConnectsStructuralMember::setAdditionalConditions(::Ifc4x3_rc3::IfcStructuralConnectionCondition* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcRelConnectsStructuralMember::SupportedLength() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc3::IfcAxis2Placement3D* Ifc4x3_rc3::IfcRelConnectsStructuralMember::ConditionCoordinateSystem() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc3::IfcAxis2Placement3D>(true); }
 void Ifc4x3_rc3::IfcRelConnectsStructuralMember::setConditionCoordinateSystem(::Ifc4x3_rc3::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -20347,7 +20347,7 @@ Ifc4x3_rc3::IfcRelConnectsWithEccentricity::IfcRelConnectsWithEccentricity(std::
 aggregate_of< ::Ifc4x3_rc3::IfcElement >::ptr Ifc4x3_rc3::IfcRelConnectsWithRealizingElements::RealizingElements() const {  aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc3::IfcElement >(); }
 void Ifc4x3_rc3::IfcRelConnectsWithRealizingElements::setRealizingElements(aggregate_of< ::Ifc4x3_rc3::IfcElement >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcRelConnectsWithRealizingElements::ConnectionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRelConnectsWithRealizingElements::declaration() const { return *IFC4X3_RC3_IfcRelConnectsWithRealizingElements_type; }
@@ -20499,7 +20499,7 @@ void Ifc4x3_rc3::IfcRelInterferesElements::setRelatedElement(::Ifc4x3_rc3::IfcIn
 ::Ifc4x3_rc3::IfcConnectionGeometry* Ifc4x3_rc3::IfcRelInterferesElements::InterferenceGeometry() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcConnectionGeometry>(true); }
 void Ifc4x3_rc3::IfcRelInterferesElements::setInterferenceGeometry(::Ifc4x3_rc3::IfcConnectionGeometry* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcRelInterferesElements::InterferenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::logic::tribool Ifc4x3_rc3::IfcRelInterferesElements::ImpliedOrder() const {  boost::logic::tribool v = *data_->getArgument(8); return v; }
 void Ifc4x3_rc3::IfcRelInterferesElements::setImpliedOrder(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -20565,9 +20565,9 @@ void Ifc4x3_rc3::IfcRelSequence::setRelatedProcess(::Ifc4x3_rc3::IfcProcess* v)
 ::Ifc4x3_rc3::IfcLagTime* Ifc4x3_rc3::IfcRelSequence::TimeLag() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcLagTime>(true); }
 void Ifc4x3_rc3::IfcRelSequence::setTimeLag(::Ifc4x3_rc3::IfcLagTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcSequenceEnum::Value > Ifc4x3_rc3::IfcRelSequence::SequenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSequenceEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc3::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x3_rc3::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSequenceEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x3_rc3::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSequenceEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcRelSequence::UserDefinedSequenceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRelSequence::declaration() const { return *IFC4X3_RC3_IfcRelSequence_type; }
@@ -20661,9 +20661,9 @@ Ifc4x3_rc3::IfcReparametrisedCompositeCurveSegment::IfcReparametrisedCompositeCu
 ::Ifc4x3_rc3::IfcRepresentationContext* Ifc4x3_rc3::IfcRepresentation::ContextOfItems() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc3::IfcRepresentationContext>(true); }
 void Ifc4x3_rc3::IfcRepresentation::setContextOfItems(::Ifc4x3_rc3::IfcRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcRepresentation::RepresentationIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcRepresentation::RepresentationType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc4x3_rc3::IfcRepresentationItem >::ptr Ifc4x3_rc3::IfcRepresentation::Items() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc3::IfcRepresentationItem >(); }
 void Ifc4x3_rc3::IfcRepresentation::setItems(aggregate_of< ::Ifc4x3_rc3::IfcRepresentationItem >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 
@@ -20678,9 +20678,9 @@ Ifc4x3_rc3::IfcRepresentation::IfcRepresentation(::Ifc4x3_rc3::IfcRepresentation
 
 // Function implementations for IfcRepresentationContext
 boost::optional< std::string > Ifc4x3_rc3::IfcRepresentationContext::ContextIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcRepresentationContext::ContextType() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc3::IfcRepresentation::list::ptr Ifc4x3_rc3::IfcRepresentationContext::RepresentationsInContext() const { return data_->getInverse(IFC4X3_RC3_IfcRepresentation_type, 0)->as<IfcRepresentation>(); }
 
@@ -20715,9 +20715,9 @@ Ifc4x3_rc3::IfcRepresentationMap::IfcRepresentationMap(::Ifc4x3_rc3::IfcAxis2Pla
 
 // Function implementations for IfcResource
 boost::optional< std::string > Ifc4x3_rc3::IfcResource::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResource::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc3::IfcRelAssignsToResource::list::ptr Ifc4x3_rc3::IfcResource::ResourceOf() const { return data_->getInverse(IFC4X3_RC3_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -20752,9 +20752,9 @@ Ifc4x3_rc3::IfcResourceConstraintRelationship::IfcResourceConstraintRelationship
 
 // Function implementations for IfcResourceLevelRelationship
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceLevelRelationship::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceLevelRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcResourceLevelRelationship::declaration() const { return *IFC4X3_RC3_IfcResourceLevelRelationship_type; }
@@ -20764,35 +20764,35 @@ Ifc4x3_rc3::IfcResourceLevelRelationship::IfcResourceLevelRelationship(boost::op
 
 // Function implementations for IfcResourceTime
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceTime::ScheduleWork() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcResourceTime::ScheduleUsage() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceTime::ScheduleContour() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceTime::LevelingDelay() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< bool > Ifc4x3_rc3::IfcResourceTime::IsOverAllocated() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceTime::StatusTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceTime::ActualWork() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcResourceTime::ActualUsage() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceTime::ActualStart() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceTime::ActualFinish() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcResourceTime::RemainingWork() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcResourceTime::RemainingUsage() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcResourceTime::Completion() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc3::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc3::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcResourceTime::declaration() const { return *IFC4X3_RC3_IfcResourceTime_type; }
@@ -20848,7 +20848,7 @@ Ifc4x3_rc3::IfcRightCircularCylinder::IfcRightCircularCylinder(::Ifc4x3_rc3::Ifc
 
 // Function implementations for IfcRoad
 boost::optional< ::Ifc4x3_rc3::IfcRoadTypeEnum::Value > Ifc4x3_rc3::IfcRoad::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcRoadTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcRoad::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRoadTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRoadTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcRoad::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRoadTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRoadTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRoad::declaration() const { return *IFC4X3_RC3_IfcRoad_type; }
@@ -20858,7 +20858,7 @@ Ifc4x3_rc3::IfcRoad::IfcRoad(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHist
 
 // Function implementations for IfcRoof
 boost::optional< ::Ifc4x3_rc3::IfcRoofTypeEnum::Value > Ifc4x3_rc3::IfcRoof::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcRoofTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRoofTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcRoofTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRoof::declaration() const { return *IFC4X3_RC3_IfcRoof_type; }
@@ -20882,9 +20882,9 @@ void Ifc4x3_rc3::IfcRoot::setGlobalId(std::string v) { {IfcWrite::IfcWriteArgume
 ::Ifc4x3_rc3::IfcOwnerHistory* Ifc4x3_rc3::IfcRoot::OwnerHistory() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc3::IfcOwnerHistory>(true); }
 void Ifc4x3_rc3::IfcRoot::setOwnerHistory(::Ifc4x3_rc3::IfcOwnerHistory* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcRoot::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcRoot::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcRoot::declaration() const { return *IFC4X3_RC3_IfcRoot_type; }
@@ -20904,7 +20904,7 @@ Ifc4x3_rc3::IfcRoundedRectangleProfileDef::IfcRoundedRectangleProfileDef(::Ifc4x
 
 // Function implementations for IfcSIUnit
 boost::optional< ::Ifc4x3_rc3::IfcSIPrefix::Value > Ifc4x3_rc3::IfcSIUnit::Prefix() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSIPrefix::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc3::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x3_rc3::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSIPrefix::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x3_rc3::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSIPrefix::ToString(*v)));}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcSIUnitName::Value Ifc4x3_rc3::IfcSIUnit::Name() const {  return ::Ifc4x3_rc3::IfcSIUnitName::FromString(*data_->getArgument(3)); }
 void Ifc4x3_rc3::IfcSIUnit::setName(::Ifc4x3_rc3::IfcSIUnitName::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcSIUnitName::ToString(v)));data_->setArgument(3,attr);} }
 
@@ -20916,7 +20916,7 @@ Ifc4x3_rc3::IfcSIUnit::IfcSIUnit(::Ifc4x3_rc3::IfcUnitEnum::Value v2_UnitType, b
 
 // Function implementations for IfcSanitaryTerminal
 boost::optional< ::Ifc4x3_rc3::IfcSanitaryTerminalTypeEnum::Value > Ifc4x3_rc3::IfcSanitaryTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSanitaryTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSanitaryTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSanitaryTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSanitaryTerminal::declaration() const { return *IFC4X3_RC3_IfcSanitaryTerminal_type; }
@@ -20936,11 +20936,11 @@ Ifc4x3_rc3::IfcSanitaryTerminalType::IfcSanitaryTerminalType(std::string v1_Glob
 
 // Function implementations for IfcSchedulingTime
 boost::optional< std::string > Ifc4x3_rc3::IfcSchedulingTime::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcDataOriginEnum::Value > Ifc4x3_rc3::IfcSchedulingTime::DataOrigin() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcDataOriginEnum::FromString(*data_->getArgument(1)); }
-void Ifc4x3_rc3::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x3_rc3::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDataOriginEnum::ToString(*v)));data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x3_rc3::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcDataOriginEnum::ToString(*v)));}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcSchedulingTime::UserDefinedDataOrigin() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSchedulingTime::declaration() const { return *IFC4X3_RC3_IfcSchedulingTime_type; }
@@ -20960,9 +20960,9 @@ Ifc4x3_rc3::IfcSeamCurve::IfcSeamCurve(::Ifc4x3_rc3::IfcCurve* v1_Curve3D, aggre
 double Ifc4x3_rc3::IfcSecondOrderPolynomialSpiral::QuadraticTerm() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcSecondOrderPolynomialSpiral::setQuadraticTerm(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSecondOrderPolynomialSpiral::LinearTerm() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcSecondOrderPolynomialSpiral::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcSecondOrderPolynomialSpiral::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSecondOrderPolynomialSpiral::ConstantTerm() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcSecondOrderPolynomialSpiral::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcSecondOrderPolynomialSpiral::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSecondOrderPolynomialSpiral::declaration() const { return *IFC4X3_RC3_IfcSecondOrderPolynomialSpiral_type; }
@@ -20990,7 +20990,7 @@ void Ifc4x3_rc3::IfcSectionReinforcementProperties::setLongitudinalStartPosition
 double Ifc4x3_rc3::IfcSectionReinforcementProperties::LongitudinalEndPosition() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcSectionReinforcementProperties::setLongitudinalEndPosition(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSectionReinforcementProperties::TransversePosition() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcReinforcingBarRoleEnum::Value Ifc4x3_rc3::IfcSectionReinforcementProperties::ReinforcementRole() const {  return ::Ifc4x3_rc3::IfcReinforcingBarRoleEnum::FromString(*data_->getArgument(3)); }
 void Ifc4x3_rc3::IfcSectionReinforcementProperties::setReinforcementRole(::Ifc4x3_rc3::IfcReinforcingBarRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcReinforcingBarRoleEnum::ToString(v)));data_->setArgument(3,attr);} }
 ::Ifc4x3_rc3::IfcSectionProperties* Ifc4x3_rc3::IfcSectionReinforcementProperties::SectionDefinition() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc3::IfcSectionProperties>(true); }
@@ -21083,7 +21083,7 @@ Ifc4x3_rc3::IfcSegmentedReferenceCurve::IfcSegmentedReferenceCurve(aggregate_of<
 
 // Function implementations for IfcSensor
 boost::optional< ::Ifc4x3_rc3::IfcSensorTypeEnum::Value > Ifc4x3_rc3::IfcSensor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSensorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSensorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSensorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSensor::declaration() const { return *IFC4X3_RC3_IfcSensor_type; }
@@ -21103,7 +21103,7 @@ Ifc4x3_rc3::IfcSensorType::IfcSensorType(std::string v1_GlobalId, ::Ifc4x3_rc3::
 
 // Function implementations for IfcShadingDevice
 boost::optional< ::Ifc4x3_rc3::IfcShadingDeviceTypeEnum::Value > Ifc4x3_rc3::IfcShadingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcShadingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcShadingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcShadingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcShadingDevice::declaration() const { return *IFC4X3_RC3_IfcShadingDevice_type; }
@@ -21125,9 +21125,9 @@ Ifc4x3_rc3::IfcShadingDeviceType::IfcShadingDeviceType(std::string v1_GlobalId,
 aggregate_of< ::Ifc4x3_rc3::IfcShapeModel >::ptr Ifc4x3_rc3::IfcShapeAspect::ShapeRepresentations() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x3_rc3::IfcShapeModel >(); }
 void Ifc4x3_rc3::IfcShapeAspect::setShapeRepresentations(aggregate_of< ::Ifc4x3_rc3::IfcShapeModel >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcShapeAspect::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcShapeAspect::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::logic::tribool Ifc4x3_rc3::IfcShapeAspect::ProductDefinitional() const {  boost::logic::tribool v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcShapeAspect::setProductDefinitional(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc3::IfcProductRepresentationSelect* Ifc4x3_rc3::IfcShapeAspect::PartOfProductDefinitionShape() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc3::IfcProductRepresentationSelect>(true); }
@@ -21169,7 +21169,7 @@ Ifc4x3_rc3::IfcShellBasedSurfaceModel::IfcShellBasedSurfaceModel(aggregate_of_in
 
 // Function implementations for IfcSign
 boost::optional< ::Ifc4x3_rc3::IfcSignTypeEnum::Value > Ifc4x3_rc3::IfcSign::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSignTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSign::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSignTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSignTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSign::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSignTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSignTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSign::declaration() const { return *IFC4X3_RC3_IfcSign_type; }
@@ -21189,7 +21189,7 @@ Ifc4x3_rc3::IfcSignType::IfcSignType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcSignal
 boost::optional< ::Ifc4x3_rc3::IfcSignalTypeEnum::Value > Ifc4x3_rc3::IfcSignal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSignalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSignal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSignalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSignalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSignal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSignalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSignalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSignal::declaration() const { return *IFC4X3_RC3_IfcSignal_type; }
@@ -21217,11 +21217,11 @@ Ifc4x3_rc3::IfcSimpleProperty::IfcSimpleProperty(std::string v1_Name, boost::opt
 
 // Function implementations for IfcSimplePropertyTemplate
 boost::optional< ::Ifc4x3_rc3::IfcSimplePropertyTemplateTypeEnum::Value > Ifc4x3_rc3::IfcSimplePropertyTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSimplePropertyTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x3_rc3::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc3::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc3::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcSimplePropertyTemplate::PrimaryMeasureType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcSimplePropertyTemplate::SecondaryMeasureType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc3::IfcPropertyEnumeration* Ifc4x3_rc3::IfcSimplePropertyTemplate::Enumerators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc3::IfcPropertyEnumeration>(true); }
 void Ifc4x3_rc3::IfcSimplePropertyTemplate::setEnumerators(::Ifc4x3_rc3::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcUnit* Ifc4x3_rc3::IfcSimplePropertyTemplate::PrimaryUnit() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc3::IfcUnit>(true); }
@@ -21229,9 +21229,9 @@ void Ifc4x3_rc3::IfcSimplePropertyTemplate::setPrimaryUnit(::Ifc4x3_rc3::IfcUnit
 ::Ifc4x3_rc3::IfcUnit* Ifc4x3_rc3::IfcSimplePropertyTemplate::SecondaryUnit() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc3::IfcUnit>(true); }
 void Ifc4x3_rc3::IfcSimplePropertyTemplate::setSecondaryUnit(::Ifc4x3_rc3::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcSimplePropertyTemplate::Expression() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcStateEnum::Value > Ifc4x3_rc3::IfcSimplePropertyTemplate::AccessState() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcStateEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc3::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x3_rc3::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcStateEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x3_rc3::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcStateEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSimplePropertyTemplate::declaration() const { return *IFC4X3_RC3_IfcSimplePropertyTemplate_type; }
@@ -21253,13 +21253,13 @@ Ifc4x3_rc3::IfcSine::IfcSine(::Ifc4x3_rc3::IfcAxis2Placement* v1_Position, doubl
 
 // Function implementations for IfcSite
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x3_rc3::IfcSite::RefLatitude() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x3_rc3::IfcSite::RefLongitude() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSite::RefElevation() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcSite::LandTitleNumber() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x3_rc3::IfcPostalAddress* Ifc4x3_rc3::IfcSite::SiteAddress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x3_rc3::IfcPostalAddress>(true); }
 void Ifc4x3_rc3::IfcSite::setSiteAddress(::Ifc4x3_rc3::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -21271,7 +21271,7 @@ Ifc4x3_rc3::IfcSite::IfcSite(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHist
 
 // Function implementations for IfcSlab
 boost::optional< ::Ifc4x3_rc3::IfcSlabTypeEnum::Value > Ifc4x3_rc3::IfcSlab::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSlabTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSlabTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSlabTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSlab::declaration() const { return *IFC4X3_RC3_IfcSlab_type; }
@@ -21307,11 +21307,11 @@ Ifc4x3_rc3::IfcSlabType::IfcSlabType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcSlippageConnectionCondition
 boost::optional< double > Ifc4x3_rc3::IfcSlippageConnectionCondition::SlippageX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSlippageConnectionCondition::SlippageY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSlippageConnectionCondition::SlippageZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSlippageConnectionCondition::declaration() const { return *IFC4X3_RC3_IfcSlippageConnectionCondition_type; }
@@ -21321,7 +21321,7 @@ Ifc4x3_rc3::IfcSlippageConnectionCondition::IfcSlippageConnectionCondition(boost
 
 // Function implementations for IfcSolarDevice
 boost::optional< ::Ifc4x3_rc3::IfcSolarDeviceTypeEnum::Value > Ifc4x3_rc3::IfcSolarDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSolarDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSolarDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSolarDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSolarDevice::declaration() const { return *IFC4X3_RC3_IfcSolarDevice_type; }
@@ -21357,9 +21357,9 @@ Ifc4x3_rc3::IfcSolidStratum::IfcSolidStratum(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcSpace
 boost::optional< ::Ifc4x3_rc3::IfcSpaceTypeEnum::Value > Ifc4x3_rc3::IfcSpace::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSpaceTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSpaceTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSpace::ElevationWithFlooring() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 ::Ifc4x3_rc3::IfcRelCoversSpaces::list::ptr Ifc4x3_rc3::IfcSpace::HasCoverings() const { return data_->getInverse(IFC4X3_RC3_IfcRelCoversSpaces_type, 4)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x3_rc3::IfcRelSpaceBoundary::list::ptr Ifc4x3_rc3::IfcSpace::BoundedBy() const { return data_->getInverse(IFC4X3_RC3_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
@@ -21371,7 +21371,7 @@ Ifc4x3_rc3::IfcSpace::IfcSpace(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHi
 
 // Function implementations for IfcSpaceHeater
 boost::optional< ::Ifc4x3_rc3::IfcSpaceHeaterTypeEnum::Value > Ifc4x3_rc3::IfcSpaceHeater::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSpaceHeaterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSpaceHeaterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSpaceHeaterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSpaceHeater::declaration() const { return *IFC4X3_RC3_IfcSpaceHeater_type; }
@@ -21393,7 +21393,7 @@ Ifc4x3_rc3::IfcSpaceHeaterType::IfcSpaceHeaterType(std::string v1_GlobalId, ::If
 ::Ifc4x3_rc3::IfcSpaceTypeEnum::Value Ifc4x3_rc3::IfcSpaceType::PredefinedType() const {  return ::Ifc4x3_rc3::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc3::IfcSpaceType::setPredefinedType(::Ifc4x3_rc3::IfcSpaceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcSpaceTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcSpaceType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSpaceType::declaration() const { return *IFC4X3_RC3_IfcSpaceType_type; }
@@ -21403,7 +21403,7 @@ Ifc4x3_rc3::IfcSpaceType::IfcSpaceType(std::string v1_GlobalId, ::Ifc4x3_rc3::If
 
 // Function implementations for IfcSpatialElement
 boost::optional< std::string > Ifc4x3_rc3::IfcSpatialElement::LongName() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc3::IfcRelContainedInSpatialStructure::list::ptr Ifc4x3_rc3::IfcSpatialElement::ContainsElements() const { return data_->getInverse(IFC4X3_RC3_IfcRelContainedInSpatialStructure_type, 5)->as<IfcRelContainedInSpatialStructure>(); }
 ::Ifc4x3_rc3::IfcRelServicesBuildings::list::ptr Ifc4x3_rc3::IfcSpatialElement::ServicedBySystems() const { return data_->getInverse(IFC4X3_RC3_IfcRelServicesBuildings_type, 5)->as<IfcRelServicesBuildings>(); }
@@ -21416,7 +21416,7 @@ Ifc4x3_rc3::IfcSpatialElement::IfcSpatialElement(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcSpatialElementType
 boost::optional< std::string > Ifc4x3_rc3::IfcSpatialElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSpatialElementType::declaration() const { return *IFC4X3_RC3_IfcSpatialElementType_type; }
@@ -21426,7 +21426,7 @@ Ifc4x3_rc3::IfcSpatialElementType::IfcSpatialElementType(std::string v1_GlobalId
 
 // Function implementations for IfcSpatialStructureElement
 boost::optional< ::Ifc4x3_rc3::IfcElementCompositionEnum::Value > Ifc4x3_rc3::IfcSpatialStructureElement::CompositionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcElementCompositionEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x3_rc3::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElementCompositionEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x3_rc3::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcElementCompositionEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSpatialStructureElement::declaration() const { return *IFC4X3_RC3_IfcSpatialStructureElement_type; }
@@ -21444,7 +21444,7 @@ Ifc4x3_rc3::IfcSpatialStructureElementType::IfcSpatialStructureElementType(std::
 
 // Function implementations for IfcSpatialZone
 boost::optional< ::Ifc4x3_rc3::IfcSpatialZoneTypeEnum::Value > Ifc4x3_rc3::IfcSpatialZone::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSpatialZoneTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSpatialZoneTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSpatialZone::declaration() const { return *IFC4X3_RC3_IfcSpatialZone_type; }
@@ -21456,7 +21456,7 @@ Ifc4x3_rc3::IfcSpatialZone::IfcSpatialZone(std::string v1_GlobalId, ::Ifc4x3_rc3
 ::Ifc4x3_rc3::IfcSpatialZoneTypeEnum::Value Ifc4x3_rc3::IfcSpatialZoneType::PredefinedType() const {  return ::Ifc4x3_rc3::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc3::IfcSpatialZoneType::setPredefinedType(::Ifc4x3_rc3::IfcSpatialZoneTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcSpatialZoneTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcSpatialZoneType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSpatialZoneType::declaration() const { return *IFC4X3_RC3_IfcSpatialZoneType_type; }
@@ -21496,7 +21496,7 @@ Ifc4x3_rc3::IfcSpiral::IfcSpiral(::Ifc4x3_rc3::IfcAxis2Placement* v1_Position) :
 
 // Function implementations for IfcStackTerminal
 boost::optional< ::Ifc4x3_rc3::IfcStackTerminalTypeEnum::Value > Ifc4x3_rc3::IfcStackTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcStackTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcStackTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcStackTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStackTerminal::declaration() const { return *IFC4X3_RC3_IfcStackTerminal_type; }
@@ -21516,7 +21516,7 @@ Ifc4x3_rc3::IfcStackTerminalType::IfcStackTerminalType(std::string v1_GlobalId,
 
 // Function implementations for IfcStair
 boost::optional< ::Ifc4x3_rc3::IfcStairTypeEnum::Value > Ifc4x3_rc3::IfcStair::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcStairTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcStair::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcStairTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcStair::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcStairTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStair::declaration() const { return *IFC4X3_RC3_IfcStair_type; }
@@ -21526,15 +21526,15 @@ Ifc4x3_rc3::IfcStair::IfcStair(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHi
 
 // Function implementations for IfcStairFlight
 boost::optional< int > Ifc4x3_rc3::IfcStairFlight::NumberOfRisers() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } int v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< int > Ifc4x3_rc3::IfcStairFlight::NumberOfTreads() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } int v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStairFlight::RiserHeight() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStairFlight::TreadLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcStairFlightTypeEnum::Value > Ifc4x3_rc3::IfcStairFlight::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcStairFlightTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc3::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcStairFlightTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcStairFlightTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStairFlight::declaration() const { return *IFC4X3_RC3_IfcStairFlight_type; }
@@ -21564,7 +21564,7 @@ Ifc4x3_rc3::IfcStairType::IfcStairType(std::string v1_GlobalId, ::Ifc4x3_rc3::If
 
 // Function implementations for IfcStructuralAction
 boost::optional< bool > Ifc4x3_rc3::IfcStructuralAction::DestabilizingLoad() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralAction::declaration() const { return *IFC4X3_RC3_IfcStructuralAction_type; }
@@ -21591,9 +21591,9 @@ void Ifc4x3_rc3::IfcStructuralAnalysisModel::setPredefinedType(::Ifc4x3_rc3::Ifc
 ::Ifc4x3_rc3::IfcAxis2Placement3D* Ifc4x3_rc3::IfcStructuralAnalysisModel::OrientationOf2DPlane() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcAxis2Placement3D>(true); }
 void Ifc4x3_rc3::IfcStructuralAnalysisModel::setOrientationOf2DPlane(::Ifc4x3_rc3::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcStructuralLoadGroup >::ptr > Ifc4x3_rc3::IfcStructuralAnalysisModel::LoadedBy() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc3::IfcStructuralLoadGroup >(); }
-void Ifc4x3_rc3::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcStructuralResultGroup >::ptr > Ifc4x3_rc3::IfcStructuralAnalysisModel::HasResults() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc3::IfcStructuralResultGroup >(); }
-void Ifc4x3_rc3::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc3::IfcObjectPlacement* Ifc4x3_rc3::IfcStructuralAnalysisModel::SharedPlacement() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc3::IfcObjectPlacement>(true); }
 void Ifc4x3_rc3::IfcStructuralAnalysisModel::setSharedPlacement(::Ifc4x3_rc3::IfcObjectPlacement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -21616,7 +21616,7 @@ Ifc4x3_rc3::IfcStructuralConnection::IfcStructuralConnection(std::string v1_Glob
 
 // Function implementations for IfcStructuralConnectionCondition
 boost::optional< std::string > Ifc4x3_rc3::IfcStructuralConnectionCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralConnectionCondition::declaration() const { return *IFC4X3_RC3_IfcStructuralConnectionCondition_type; }
@@ -21626,7 +21626,7 @@ Ifc4x3_rc3::IfcStructuralConnectionCondition::IfcStructuralConnectionCondition(b
 
 // Function implementations for IfcStructuralCurveAction
 boost::optional< ::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::Value > Ifc4x3_rc3::IfcStructuralCurveAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc3::IfcStructuralCurveActivityTypeEnum::Value Ifc4x3_rc3::IfcStructuralCurveAction::PredefinedType() const {  return ::Ifc4x3_rc3::IfcStructuralCurveActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x3_rc3::IfcStructuralCurveAction::setPredefinedType(::Ifc4x3_rc3::IfcStructuralCurveActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcStructuralCurveActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -21695,7 +21695,7 @@ Ifc4x3_rc3::IfcStructuralLinearAction::IfcStructuralLinearAction(std::string v1_
 
 // Function implementations for IfcStructuralLoad
 boost::optional< std::string > Ifc4x3_rc3::IfcStructuralLoad::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralLoad::declaration() const { return *IFC4X3_RC3_IfcStructuralLoad_type; }
@@ -21705,7 +21705,7 @@ Ifc4x3_rc3::IfcStructuralLoad::IfcStructuralLoad(boost::optional< std::string >
 
 // Function implementations for IfcStructuralLoadCase
 boost::optional< std::vector< double > /*[3:3]*/ > Ifc4x3_rc3::IfcStructuralLoadCase::SelfWeightCoefficients() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< double > /*[3:3]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralLoadCase::declaration() const { return *IFC4X3_RC3_IfcStructuralLoadCase_type; }
@@ -21717,7 +21717,7 @@ Ifc4x3_rc3::IfcStructuralLoadCase::IfcStructuralLoadCase(std::string v1_GlobalId
 aggregate_of< ::Ifc4x3_rc3::IfcStructuralLoadOrResult >::ptr Ifc4x3_rc3::IfcStructuralLoadConfiguration::Values() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc3::IfcStructuralLoadOrResult >(); }
 void Ifc4x3_rc3::IfcStructuralLoadConfiguration::setValues(aggregate_of< ::Ifc4x3_rc3::IfcStructuralLoadOrResult >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::vector< std::vector< double > > > Ifc4x3_rc3::IfcStructuralLoadConfiguration::Locations() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralLoadConfiguration::declaration() const { return *IFC4X3_RC3_IfcStructuralLoadConfiguration_type; }
@@ -21733,9 +21733,9 @@ void Ifc4x3_rc3::IfcStructuralLoadGroup::setActionType(::Ifc4x3_rc3::IfcActionTy
 ::Ifc4x3_rc3::IfcActionSourceTypeEnum::Value Ifc4x3_rc3::IfcStructuralLoadGroup::ActionSource() const {  return ::Ifc4x3_rc3::IfcActionSourceTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc3::IfcStructuralLoadGroup::setActionSource(::Ifc4x3_rc3::IfcActionSourceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcActionSourceTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadGroup::Coefficient() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcStructuralLoadGroup::Purpose() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 ::Ifc4x3_rc3::IfcStructuralResultGroup::list::ptr Ifc4x3_rc3::IfcStructuralLoadGroup::SourceOfResultGroup() const { return data_->getInverse(IFC4X3_RC3_IfcStructuralResultGroup_type, 6)->as<IfcStructuralResultGroup>(); }
 ::Ifc4x3_rc3::IfcStructuralAnalysisModel::list::ptr Ifc4x3_rc3::IfcStructuralLoadGroup::LoadGroupFor() const { return data_->getInverse(IFC4X3_RC3_IfcStructuralAnalysisModel_type, 7)->as<IfcStructuralAnalysisModel>(); }
@@ -21747,17 +21747,17 @@ Ifc4x3_rc3::IfcStructuralLoadGroup::IfcStructuralLoadGroup(std::string v1_Global
 
 // Function implementations for IfcStructuralLoadLinearForce
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadLinearForce::LinearForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadLinearForce::LinearForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadLinearForce::LinearForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadLinearForce::LinearMomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadLinearForce::LinearMomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadLinearForce::LinearMomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralLoadLinearForce::declaration() const { return *IFC4X3_RC3_IfcStructuralLoadLinearForce_type; }
@@ -21775,11 +21775,11 @@ Ifc4x3_rc3::IfcStructuralLoadOrResult::IfcStructuralLoadOrResult(boost::optional
 
 // Function implementations for IfcStructuralLoadPlanarForce
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadPlanarForce::PlanarForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadPlanarForce::PlanarForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadPlanarForce::PlanarForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralLoadPlanarForce::declaration() const { return *IFC4X3_RC3_IfcStructuralLoadPlanarForce_type; }
@@ -21789,17 +21789,17 @@ Ifc4x3_rc3::IfcStructuralLoadPlanarForce::IfcStructuralLoadPlanarForce(boost::op
 
 // Function implementations for IfcStructuralLoadSingleDisplacement
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::DisplacementX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::DisplacementY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::DisplacementZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::declaration() const { return *IFC4X3_RC3_IfcStructuralLoadSingleDisplacement_type; }
@@ -21809,7 +21809,7 @@ Ifc4x3_rc3::IfcStructuralLoadSingleDisplacement::IfcStructuralLoadSingleDisplace
 
 // Function implementations for IfcStructuralLoadSingleDisplacementDistortion
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleDisplacementDistortion::Distortion() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralLoadSingleDisplacementDistortion::declaration() const { return *IFC4X3_RC3_IfcStructuralLoadSingleDisplacementDistortion_type; }
@@ -21819,17 +21819,17 @@ Ifc4x3_rc3::IfcStructuralLoadSingleDisplacementDistortion::IfcStructuralLoadSing
 
 // Function implementations for IfcStructuralLoadSingleForce
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleForce::ForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleForce::ForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleForce::ForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleForce::MomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleForce::MomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleForce::MomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralLoadSingleForce::declaration() const { return *IFC4X3_RC3_IfcStructuralLoadSingleForce_type; }
@@ -21839,7 +21839,7 @@ Ifc4x3_rc3::IfcStructuralLoadSingleForce::IfcStructuralLoadSingleForce(boost::op
 
 // Function implementations for IfcStructuralLoadSingleForceWarping
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadSingleForceWarping::WarpingMoment() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralLoadSingleForceWarping::declaration() const { return *IFC4X3_RC3_IfcStructuralLoadSingleForceWarping_type; }
@@ -21857,11 +21857,11 @@ Ifc4x3_rc3::IfcStructuralLoadStatic::IfcStructuralLoadStatic(boost::optional< st
 
 // Function implementations for IfcStructuralLoadTemperature
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadTemperature::DeltaTConstant() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadTemperature::DeltaTY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralLoadTemperature::DeltaTZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralLoadTemperature::declaration() const { return *IFC4X3_RC3_IfcStructuralLoadTemperature_type; }
@@ -21937,7 +21937,7 @@ Ifc4x3_rc3::IfcStructuralResultGroup::IfcStructuralResultGroup(std::string v1_Gl
 
 // Function implementations for IfcStructuralSurfaceAction
 boost::optional< ::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::Value > Ifc4x3_rc3::IfcStructuralSurfaceAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc3::IfcStructuralSurfaceActivityTypeEnum::Value Ifc4x3_rc3::IfcStructuralSurfaceAction::PredefinedType() const {  return ::Ifc4x3_rc3::IfcStructuralSurfaceActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x3_rc3::IfcStructuralSurfaceAction::setPredefinedType(::Ifc4x3_rc3::IfcStructuralSurfaceActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcStructuralSurfaceActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -21959,7 +21959,7 @@ Ifc4x3_rc3::IfcStructuralSurfaceConnection::IfcStructuralSurfaceConnection(std::
 ::Ifc4x3_rc3::IfcStructuralSurfaceMemberTypeEnum::Value Ifc4x3_rc3::IfcStructuralSurfaceMember::PredefinedType() const {  return ::Ifc4x3_rc3::IfcStructuralSurfaceMemberTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc3::IfcStructuralSurfaceMember::setPredefinedType(::Ifc4x3_rc3::IfcStructuralSurfaceMemberTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcStructuralSurfaceMemberTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcStructuralSurfaceMember::Thickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStructuralSurfaceMember::declaration() const { return *IFC4X3_RC3_IfcStructuralSurfaceMember_type; }
@@ -21999,7 +21999,7 @@ void Ifc4x3_rc3::IfcStyledItem::setItem(::Ifc4x3_rc3::IfcRepresentationItem* v)
 aggregate_of< ::Ifc4x3_rc3::IfcPresentationStyle >::ptr Ifc4x3_rc3::IfcStyledItem::Styles() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc3::IfcPresentationStyle >(); }
 void Ifc4x3_rc3::IfcStyledItem::setStyles(aggregate_of< ::Ifc4x3_rc3::IfcPresentationStyle >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcStyledItem::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcStyledItem::declaration() const { return *IFC4X3_RC3_IfcStyledItem_type; }
@@ -22017,7 +22017,7 @@ Ifc4x3_rc3::IfcStyledRepresentation::IfcStyledRepresentation(::Ifc4x3_rc3::IfcRe
 
 // Function implementations for IfcSubContractResource
 boost::optional< ::Ifc4x3_rc3::IfcSubContractResourceTypeEnum::Value > Ifc4x3_rc3::IfcSubContractResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSubContractResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSubContractResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSubContractResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSubContractResource::declaration() const { return *IFC4X3_RC3_IfcSubContractResource_type; }
@@ -22079,7 +22079,7 @@ Ifc4x3_rc3::IfcSurfaceCurveSweptAreaSolid::IfcSurfaceCurveSweptAreaSolid(::Ifc4x
 
 // Function implementations for IfcSurfaceFeature
 boost::optional< ::Ifc4x3_rc3::IfcSurfaceFeatureTypeEnum::Value > Ifc4x3_rc3::IfcSurfaceFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSurfaceFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSurfaceFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSurfaceFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSurfaceFeature::declaration() const { return *IFC4X3_RC3_IfcSurfaceFeature_type; }
@@ -22111,11 +22111,11 @@ Ifc4x3_rc3::IfcSurfaceOfRevolution::IfcSurfaceOfRevolution(::Ifc4x3_rc3::IfcProf
 
 // Function implementations for IfcSurfaceReinforcementArea
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x3_rc3::IfcSurfaceReinforcementArea::SurfaceReinforcement1() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x3_rc3::IfcSurfaceReinforcementArea::SurfaceReinforcement2() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSurfaceReinforcementArea::ShearReinforcement() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSurfaceReinforcementArea::declaration() const { return *IFC4X3_RC3_IfcSurfaceReinforcementArea_type; }
@@ -22153,9 +22153,9 @@ Ifc4x3_rc3::IfcSurfaceStyleLighting::IfcSurfaceStyleLighting(::Ifc4x3_rc3::IfcCo
 
 // Function implementations for IfcSurfaceStyleRefraction
 boost::optional< double > Ifc4x3_rc3::IfcSurfaceStyleRefraction::RefractionIndex() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSurfaceStyleRefraction::DispersionFactor() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSurfaceStyleRefraction::declaration() const { return *IFC4X3_RC3_IfcSurfaceStyleRefraction_type; }
@@ -22189,7 +22189,7 @@ Ifc4x3_rc3::IfcSurfaceStyleRendering::IfcSurfaceStyleRendering(::Ifc4x3_rc3::Ifc
 ::Ifc4x3_rc3::IfcColourRgb* Ifc4x3_rc3::IfcSurfaceStyleShading::SurfaceColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc3::IfcColourRgb>(true); }
 void Ifc4x3_rc3::IfcSurfaceStyleShading::setSurfaceColour(::Ifc4x3_rc3::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSurfaceStyleShading::Transparency() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSurfaceStyleShading::declaration() const { return *IFC4X3_RC3_IfcSurfaceStyleShading_type; }
@@ -22213,11 +22213,11 @@ void Ifc4x3_rc3::IfcSurfaceTexture::setRepeatS(bool v) { {IfcWrite::IfcWriteArgu
 bool Ifc4x3_rc3::IfcSurfaceTexture::RepeatT() const {  bool v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcSurfaceTexture::setRepeatT(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcSurfaceTexture::Mode() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcCartesianTransformationOperator2D* Ifc4x3_rc3::IfcSurfaceTexture::TextureTransform() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x3_rc3::IfcSurfaceTexture::setTextureTransform(::Ifc4x3_rc3::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcSurfaceTexture::Parameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc3::IfcTextureCoordinate::list::ptr Ifc4x3_rc3::IfcSurfaceTexture::IsMappedBy() const { return data_->getInverse(IFC4X3_RC3_IfcTextureCoordinate_type, 0)->as<IfcTextureCoordinate>(); }
 ::Ifc4x3_rc3::IfcSurfaceStyleWithTextures::list::ptr Ifc4x3_rc3::IfcSurfaceTexture::UsedInStyles() const { return data_->getInverse(IFC4X3_RC3_IfcSurfaceStyleWithTextures_type, 0)->as<IfcSurfaceStyleWithTextures>(); }
@@ -22245,11 +22245,11 @@ void Ifc4x3_rc3::IfcSweptDiskSolid::setDirectrix(::Ifc4x3_rc3::IfcCurve* v) { {I
 double Ifc4x3_rc3::IfcSweptDiskSolid::Radius() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcSweptDiskSolid::setRadius(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSweptDiskSolid::InnerRadius() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSweptDiskSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcSweptDiskSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSweptDiskSolid::declaration() const { return *IFC4X3_RC3_IfcSweptDiskSolid_type; }
@@ -22259,7 +22259,7 @@ Ifc4x3_rc3::IfcSweptDiskSolid::IfcSweptDiskSolid(::Ifc4x3_rc3::IfcCurve* v1_Dire
 
 // Function implementations for IfcSweptDiskSolidPolygonal
 boost::optional< double > Ifc4x3_rc3::IfcSweptDiskSolidPolygonal::FilletRadius() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSweptDiskSolidPolygonal::declaration() const { return *IFC4X3_RC3_IfcSweptDiskSolidPolygonal_type; }
@@ -22281,7 +22281,7 @@ Ifc4x3_rc3::IfcSweptSurface::IfcSweptSurface(::Ifc4x3_rc3::IfcProfileDef* v1_Swe
 
 // Function implementations for IfcSwitchingDevice
 boost::optional< ::Ifc4x3_rc3::IfcSwitchingDeviceTypeEnum::Value > Ifc4x3_rc3::IfcSwitchingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSwitchingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSwitchingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSwitchingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSwitchingDevice::declaration() const { return *IFC4X3_RC3_IfcSwitchingDevice_type; }
@@ -22311,7 +22311,7 @@ Ifc4x3_rc3::IfcSystem::IfcSystem(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwner
 
 // Function implementations for IfcSystemFurnitureElement
 boost::optional< ::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x3_rc3::IfcSystemFurnitureElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSystemFurnitureElement::declaration() const { return *IFC4X3_RC3_IfcSystemFurnitureElement_type; }
@@ -22321,7 +22321,7 @@ Ifc4x3_rc3::IfcSystemFurnitureElement::IfcSystemFurnitureElement(std::string v1_
 
 // Function implementations for IfcSystemFurnitureElementType
 boost::optional< ::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x3_rc3::IfcSystemFurnitureElementType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcSystemFurnitureElementType::declaration() const { return *IFC4X3_RC3_IfcSystemFurnitureElementType_type; }
@@ -22339,15 +22339,15 @@ void Ifc4x3_rc3::IfcTShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc3::IfcTShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcTShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTShapeProfileDef::WebEdgeRadius() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTShapeProfileDef::WebSlope() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTShapeProfileDef::declaration() const { return *IFC4X3_RC3_IfcTShapeProfileDef_type; }
@@ -22357,11 +22357,11 @@ Ifc4x3_rc3::IfcTShapeProfileDef::IfcTShapeProfileDef(::Ifc4x3_rc3::IfcProfileTyp
 
 // Function implementations for IfcTable
 boost::optional< std::string > Ifc4x3_rc3::IfcTable::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcTableRow >::ptr > Ifc4x3_rc3::IfcTable::Rows() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc3::IfcTableRow >(); }
-void Ifc4x3_rc3::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcTableColumn >::ptr > Ifc4x3_rc3::IfcTable::Columns() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc3::IfcTableColumn >(); }
-void Ifc4x3_rc3::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTable::declaration() const { return *IFC4X3_RC3_IfcTable_type; }
@@ -22371,11 +22371,11 @@ Ifc4x3_rc3::IfcTable::IfcTable(boost::optional< std::string > v1_Name, boost::op
 
 // Function implementations for IfcTableColumn
 boost::optional< std::string > Ifc4x3_rc3::IfcTableColumn::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTableColumn::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTableColumn::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcUnit* Ifc4x3_rc3::IfcTableColumn::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcUnit>(true); }
 void Ifc4x3_rc3::IfcTableColumn::setUnit(::Ifc4x3_rc3::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc3::IfcReference* Ifc4x3_rc3::IfcTableColumn::ReferencePath() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc3::IfcReference>(true); }
@@ -22389,9 +22389,9 @@ Ifc4x3_rc3::IfcTableColumn::IfcTableColumn(boost::optional< std::string > v1_Ide
 
 // Function implementations for IfcTableRow
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc3::IfcTableRow::RowCells() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc3::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc3::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< bool > Ifc4x3_rc3::IfcTableRow::IsHeading() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTableRow::declaration() const { return *IFC4X3_RC3_IfcTableRow_type; }
@@ -22401,7 +22401,7 @@ Ifc4x3_rc3::IfcTableRow::IfcTableRow(boost::optional< aggregate_of_instance::ptr
 
 // Function implementations for IfcTank
 boost::optional< ::Ifc4x3_rc3::IfcTankTypeEnum::Value > Ifc4x3_rc3::IfcTank::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcTankTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcTank::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTankTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcTank::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTankTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTank::declaration() const { return *IFC4X3_RC3_IfcTank_type; }
@@ -22421,17 +22421,17 @@ Ifc4x3_rc3::IfcTankType::IfcTankType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcTask
 boost::optional< std::string > Ifc4x3_rc3::IfcTask::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTask::WorkMethod() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 bool Ifc4x3_rc3::IfcTask::IsMilestone() const {  bool v = *data_->getArgument(9); return v; }
 void Ifc4x3_rc3::IfcTask::setIsMilestone(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< int > Ifc4x3_rc3::IfcTask::Priority() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } int v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc3::IfcTaskTime* Ifc4x3_rc3::IfcTask::TaskTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc3::IfcTaskTime>(true); }
 void Ifc4x3_rc3::IfcTask::setTaskTime(::Ifc4x3_rc3::IfcTaskTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcTaskTypeEnum::Value > Ifc4x3_rc3::IfcTask::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcTaskTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc3::IfcTask::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTaskTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcTask::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTaskTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTask::declaration() const { return *IFC4X3_RC3_IfcTask_type; }
@@ -22441,39 +22441,39 @@ Ifc4x3_rc3::IfcTask::IfcTask(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwnerHist
 
 // Function implementations for IfcTaskTime
 boost::optional< ::Ifc4x3_rc3::IfcTaskDurationEnum::Value > Ifc4x3_rc3::IfcTaskTime::DurationType() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcTaskDurationEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x3_rc3::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x3_rc3::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTaskDurationEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x3_rc3::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTaskDurationEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::ScheduleDuration() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::EarlyStart() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::EarlyFinish() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::LateStart() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::LateFinish() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::FreeFloat() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::TotalFloat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< bool > Ifc4x3_rc3::IfcTaskTime::IsCritical() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } bool v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::StatusTime() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::ActualDuration() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::ActualStart() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } std::string v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::ActualFinish() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } std::string v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskTime::RemainingTime() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTaskTime::Completion() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } double v = *data_->getArgument(19); return v; }
-void Ifc4x3_rc3::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x3_rc3::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTaskTime::declaration() const { return *IFC4X3_RC3_IfcTaskTime_type; }
@@ -22495,7 +22495,7 @@ Ifc4x3_rc3::IfcTaskTimeRecurring::IfcTaskTimeRecurring(boost::optional< std::str
 ::Ifc4x3_rc3::IfcTaskTypeEnum::Value Ifc4x3_rc3::IfcTaskType::PredefinedType() const {  return ::Ifc4x3_rc3::IfcTaskTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc3::IfcTaskType::setPredefinedType(::Ifc4x3_rc3::IfcTaskTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcTaskTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTaskType::WorkMethod() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTaskType::declaration() const { return *IFC4X3_RC3_IfcTaskType_type; }
@@ -22505,17 +22505,17 @@ Ifc4x3_rc3::IfcTaskType::IfcTaskType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcTelecomAddress
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcTelecomAddress::TelephoneNumbers() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcTelecomAddress::FacsimileNumbers() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTelecomAddress::PagerNumber() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcTelecomAddress::ElectronicMailAddresses() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTelecomAddress::WWWHomePageURL() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc3::IfcTelecomAddress::MessagingIDs() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTelecomAddress::declaration() const { return *IFC4X3_RC3_IfcTelecomAddress_type; }
@@ -22525,21 +22525,21 @@ Ifc4x3_rc3::IfcTelecomAddress::IfcTelecomAddress(boost::optional< ::Ifc4x3_rc3::
 
 // Function implementations for IfcTendon
 boost::optional< ::Ifc4x3_rc3::IfcTendonTypeEnum::Value > Ifc4x3_rc3::IfcTendon::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTendonTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTendonTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTendon::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTendon::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTendon::TensionForce() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTendon::PreStress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc3::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTendon::FrictionCoefficient() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc3::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc3::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTendon::AnchorageSlip() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc3::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc3::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTendon::MinCurvatureRadius() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc3::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc3::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTendon::declaration() const { return *IFC4X3_RC3_IfcTendon_type; }
@@ -22549,7 +22549,7 @@ Ifc4x3_rc3::IfcTendon::IfcTendon(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwner
 
 // Function implementations for IfcTendonAnchor
 boost::optional< ::Ifc4x3_rc3::IfcTendonAnchorTypeEnum::Value > Ifc4x3_rc3::IfcTendonAnchor::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcTendonAnchorTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTendonAnchorTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTendonAnchorTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTendonAnchor::declaration() const { return *IFC4X3_RC3_IfcTendonAnchor_type; }
@@ -22591,11 +22591,11 @@ Ifc4x3_rc3::IfcTendonConduitType::IfcTendonConduitType(std::string v1_GlobalId,
 ::Ifc4x3_rc3::IfcTendonTypeEnum::Value Ifc4x3_rc3::IfcTendonType::PredefinedType() const {  return ::Ifc4x3_rc3::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc3::IfcTendonType::setPredefinedType(::Ifc4x3_rc3::IfcTendonTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcTendonTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTendonType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTendonType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcTendonType::SheathDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTendonType::declaration() const { return *IFC4X3_RC3_IfcTendonType_type; }
@@ -22657,7 +22657,7 @@ void Ifc4x3_rc3::IfcTextStyle::setTextStyle(::Ifc4x3_rc3::IfcTextStyleTextModel*
 ::Ifc4x3_rc3::IfcTextFontSelect* Ifc4x3_rc3::IfcTextStyle::TextFontStyle() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcTextFontSelect>(true); }
 void Ifc4x3_rc3::IfcTextStyle::setTextFontStyle(::Ifc4x3_rc3::IfcTextFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x3_rc3::IfcTextStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTextStyle::declaration() const { return *IFC4X3_RC3_IfcTextStyle_type; }
@@ -22669,11 +22669,11 @@ Ifc4x3_rc3::IfcTextStyle::IfcTextStyle(boost::optional< std::string > v1_Name, :
 std::vector< std::string > /*[1:?]*/ Ifc4x3_rc3::IfcTextStyleFontModel::FontFamily() const {  std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcTextStyleFontModel::setFontFamily(std::vector< std::string > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTextStyleFontModel::FontStyle() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTextStyleFontModel::FontVariant() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTextStyleFontModel::FontWeight() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc3::IfcSizeSelect* Ifc4x3_rc3::IfcTextStyleFontModel::FontSize() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc3::IfcSizeSelect>(true); }
 void Ifc4x3_rc3::IfcTextStyleFontModel::setFontSize(::Ifc4x3_rc3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -22699,15 +22699,15 @@ Ifc4x3_rc3::IfcTextStyleForDefinedFont::IfcTextStyleForDefinedFont(::Ifc4x3_rc3:
 ::Ifc4x3_rc3::IfcSizeSelect* Ifc4x3_rc3::IfcTextStyleTextModel::TextIndent() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc3::IfcSizeSelect>(true); }
 void Ifc4x3_rc3::IfcTextStyleTextModel::setTextIndent(::Ifc4x3_rc3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTextStyleTextModel::TextAlign() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTextStyleTextModel::TextDecoration() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc3::IfcSizeSelect* Ifc4x3_rc3::IfcTextStyleTextModel::LetterSpacing() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcSizeSelect>(true); }
 void Ifc4x3_rc3::IfcTextStyleTextModel::setLetterSpacing(::Ifc4x3_rc3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc3::IfcSizeSelect* Ifc4x3_rc3::IfcTextStyleTextModel::WordSpacing() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc3::IfcSizeSelect>(true); }
 void Ifc4x3_rc3::IfcTextStyleTextModel::setWordSpacing(::Ifc4x3_rc3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTextStyleTextModel::TextTransform() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc3::IfcSizeSelect* Ifc4x3_rc3::IfcTextStyleTextModel::LineHeight() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc3::IfcSizeSelect>(true); }
 void Ifc4x3_rc3::IfcTextStyleTextModel::setLineHeight(::Ifc4x3_rc3::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -22731,7 +22731,7 @@ Ifc4x3_rc3::IfcTextureCoordinate::IfcTextureCoordinate(aggregate_of< ::Ifc4x3_rc
 std::string Ifc4x3_rc3::IfcTextureCoordinateGenerator::Mode() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcTextureCoordinateGenerator::setMode(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[1:?]*/ > Ifc4x3_rc3::IfcTextureCoordinateGenerator::Parameter() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTextureCoordinateGenerator::declaration() const { return *IFC4X3_RC3_IfcTextureCoordinateGenerator_type; }
@@ -22775,11 +22775,11 @@ Ifc4x3_rc3::IfcTextureVertexList::IfcTextureVertexList(std::vector< std::vector<
 double Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::QubicTerm() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::setQubicTerm(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::QuadraticTerm() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::setQuadraticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::setQuadraticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::LinearTerm() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::ConstantTerm() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcThirdOrderPolynomialSpiral::declaration() const { return *IFC4X3_RC3_IfcThirdOrderPolynomialSpiral_type; }
@@ -22803,7 +22803,7 @@ Ifc4x3_rc3::IfcTimePeriod::IfcTimePeriod(std::string v1_StartTime, std::string v
 std::string Ifc4x3_rc3::IfcTimeSeries::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc3::IfcTimeSeries::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTimeSeries::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 std::string Ifc4x3_rc3::IfcTimeSeries::StartTime() const {  std::string v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc3::IfcTimeSeries::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::string Ifc4x3_rc3::IfcTimeSeries::EndTime() const {  std::string v = *data_->getArgument(3); return v; }
@@ -22813,7 +22813,7 @@ void Ifc4x3_rc3::IfcTimeSeries::setTimeSeriesDataType(::Ifc4x3_rc3::IfcTimeSerie
 ::Ifc4x3_rc3::IfcDataOriginEnum::Value Ifc4x3_rc3::IfcTimeSeries::DataOrigin() const {  return ::Ifc4x3_rc3::IfcDataOriginEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc3::IfcTimeSeries::setDataOrigin(::Ifc4x3_rc3::IfcDataOriginEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcDataOriginEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTimeSeries::UserDefinedDataOrigin() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc3::IfcUnit* Ifc4x3_rc3::IfcTimeSeries::Unit() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc3::IfcUnit>(true); }
 void Ifc4x3_rc3::IfcTimeSeries::setUnit(::Ifc4x3_rc3::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 
@@ -22864,7 +22864,7 @@ Ifc4x3_rc3::IfcToroidalSurface::IfcToroidalSurface(::Ifc4x3_rc3::IfcAxis2Placeme
 
 // Function implementations for IfcTrackElement
 boost::optional< ::Ifc4x3_rc3::IfcTrackElementTypeEnum::Value > Ifc4x3_rc3::IfcTrackElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcTrackElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcTrackElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTrackElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTrackElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcTrackElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTrackElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTrackElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTrackElement::declaration() const { return *IFC4X3_RC3_IfcTrackElement_type; }
@@ -22884,7 +22884,7 @@ Ifc4x3_rc3::IfcTrackElementType::IfcTrackElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcTransformer
 boost::optional< ::Ifc4x3_rc3::IfcTransformerTypeEnum::Value > Ifc4x3_rc3::IfcTransformer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcTransformerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTransformerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTransformerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTransformer::declaration() const { return *IFC4X3_RC3_IfcTransformer_type; }
@@ -22940,13 +22940,13 @@ Ifc4x3_rc3::IfcTrapeziumProfileDef::IfcTrapeziumProfileDef(::Ifc4x3_rc3::IfcProf
 
 // Function implementations for IfcTriangulatedFaceSet
 boost::optional< std::vector< std::vector< double > > > Ifc4x3_rc3::IfcTriangulatedFaceSet::Normals() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc3::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc3::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc3::IfcTriangulatedFaceSet::Closed() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc3::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc3::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::vector< std::vector< int > > Ifc4x3_rc3::IfcTriangulatedFaceSet::CoordIndex() const {  std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc3::IfcTriangulatedFaceSet::setCoordIndex(std::vector< std::vector< int > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc3::IfcTriangulatedFaceSet::PnIndex() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTriangulatedFaceSet::declaration() const { return *IFC4X3_RC3_IfcTriangulatedFaceSet_type; }
@@ -22984,7 +22984,7 @@ Ifc4x3_rc3::IfcTrimmedCurve::IfcTrimmedCurve(::Ifc4x3_rc3::IfcCurve* v1_BasisCur
 
 // Function implementations for IfcTubeBundle
 boost::optional< ::Ifc4x3_rc3::IfcTubeBundleTypeEnum::Value > Ifc4x3_rc3::IfcTubeBundle::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcTubeBundleTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTubeBundleTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcTubeBundleTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcTubeBundle::declaration() const { return *IFC4X3_RC3_IfcTubeBundle_type; }
@@ -23004,9 +23004,9 @@ Ifc4x3_rc3::IfcTubeBundleType::IfcTubeBundleType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcTypeObject
 boost::optional< std::string > Ifc4x3_rc3::IfcTypeObject::ApplicableOccurrence() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPropertySetDefinition >::ptr > Ifc4x3_rc3::IfcTypeObject::HasPropertySets() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc3::IfcPropertySetDefinition >(); }
-void Ifc4x3_rc3::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc3::IfcRelDefinesByType::list::ptr Ifc4x3_rc3::IfcTypeObject::Types() const { return data_->getInverse(IFC4X3_RC3_IfcRelDefinesByType_type, 5)->as<IfcRelDefinesByType>(); }
 
@@ -23017,11 +23017,11 @@ Ifc4x3_rc3::IfcTypeObject::IfcTypeObject(std::string v1_GlobalId, ::Ifc4x3_rc3::
 
 // Function implementations for IfcTypeProcess
 boost::optional< std::string > Ifc4x3_rc3::IfcTypeProcess::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTypeProcess::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTypeProcess::ProcessType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc3::IfcRelAssignsToProcess::list::ptr Ifc4x3_rc3::IfcTypeProcess::OperatesOn() const { return data_->getInverse(IFC4X3_RC3_IfcRelAssignsToProcess_type, 6)->as<IfcRelAssignsToProcess>(); }
 
@@ -23032,9 +23032,9 @@ Ifc4x3_rc3::IfcTypeProcess::IfcTypeProcess(std::string v1_GlobalId, ::Ifc4x3_rc3
 
 // Function implementations for IfcTypeProduct
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcRepresentationMap >::ptr > Ifc4x3_rc3::IfcTypeProduct::RepresentationMaps() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc3::IfcRepresentationMap >(); }
-void Ifc4x3_rc3::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTypeProduct::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc3::IfcRelAssignsToProduct::list::ptr Ifc4x3_rc3::IfcTypeProduct::ReferencedBy() const { return data_->getInverse(IFC4X3_RC3_IfcRelAssignsToProduct_type, 6)->as<IfcRelAssignsToProduct>(); }
 
@@ -23045,11 +23045,11 @@ Ifc4x3_rc3::IfcTypeProduct::IfcTypeProduct(std::string v1_GlobalId, ::Ifc4x3_rc3
 
 // Function implementations for IfcTypeResource
 boost::optional< std::string > Ifc4x3_rc3::IfcTypeResource::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTypeResource::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcTypeResource::ResourceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc3::IfcRelAssignsToResource::list::ptr Ifc4x3_rc3::IfcTypeResource::ResourceOf() const { return data_->getInverse(IFC4X3_RC3_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -23068,11 +23068,11 @@ void Ifc4x3_rc3::IfcUShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc3::IfcUShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcUShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcUShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcUShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcUShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcUShapeProfileDef::declaration() const { return *IFC4X3_RC3_IfcUShapeProfileDef_type; }
@@ -23092,7 +23092,7 @@ Ifc4x3_rc3::IfcUnitAssignment::IfcUnitAssignment(aggregate_of_instance::ptr v1_U
 
 // Function implementations for IfcUnitaryControlElement
 boost::optional< ::Ifc4x3_rc3::IfcUnitaryControlElementTypeEnum::Value > Ifc4x3_rc3::IfcUnitaryControlElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcUnitaryControlElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcUnitaryControlElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcUnitaryControlElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcUnitaryControlElement::declaration() const { return *IFC4X3_RC3_IfcUnitaryControlElement_type; }
@@ -23112,7 +23112,7 @@ Ifc4x3_rc3::IfcUnitaryControlElementType::IfcUnitaryControlElementType(std::stri
 
 // Function implementations for IfcUnitaryEquipment
 boost::optional< ::Ifc4x3_rc3::IfcUnitaryEquipmentTypeEnum::Value > Ifc4x3_rc3::IfcUnitaryEquipment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcUnitaryEquipmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcUnitaryEquipmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcUnitaryEquipmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcUnitaryEquipment::declaration() const { return *IFC4X3_RC3_IfcUnitaryEquipment_type; }
@@ -23132,7 +23132,7 @@ Ifc4x3_rc3::IfcUnitaryEquipmentType::IfcUnitaryEquipmentType(std::string v1_Glob
 
 // Function implementations for IfcValve
 boost::optional< ::Ifc4x3_rc3::IfcValveTypeEnum::Value > Ifc4x3_rc3::IfcValve::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcValveTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcValve::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcValveTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcValve::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcValveTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcValve::declaration() const { return *IFC4X3_RC3_IfcValve_type; }
@@ -23192,7 +23192,7 @@ Ifc4x3_rc3::IfcVertexPoint::IfcVertexPoint(::Ifc4x3_rc3::IfcPoint* v1_VertexGeom
 
 // Function implementations for IfcVibrationDamper
 boost::optional< ::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::Value > Ifc4x3_rc3::IfcVibrationDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcVibrationDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcVibrationDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcVibrationDamper::declaration() const { return *IFC4X3_RC3_IfcVibrationDamper_type; }
@@ -23202,7 +23202,7 @@ Ifc4x3_rc3::IfcVibrationDamper::IfcVibrationDamper(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcVibrationDamperType
 boost::optional< ::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::Value > Ifc4x3_rc3::IfcVibrationDamperType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc3::IfcVibrationDamperType::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcVibrationDamperType::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcVibrationDamperTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcVibrationDamperType::declaration() const { return *IFC4X3_RC3_IfcVibrationDamperType_type; }
@@ -23212,7 +23212,7 @@ Ifc4x3_rc3::IfcVibrationDamperType::IfcVibrationDamperType(std::string v1_Global
 
 // Function implementations for IfcVibrationIsolator
 boost::optional< ::Ifc4x3_rc3::IfcVibrationIsolatorTypeEnum::Value > Ifc4x3_rc3::IfcVibrationIsolator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcVibrationIsolatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcVibrationIsolatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcVibrationIsolatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcVibrationIsolator::declaration() const { return *IFC4X3_RC3_IfcVibrationIsolator_type; }
@@ -23276,7 +23276,7 @@ Ifc4x3_rc3::IfcVoidStratum::IfcVoidStratum(std::string v1_GlobalId, ::Ifc4x3_rc3
 
 // Function implementations for IfcVoidingFeature
 boost::optional< ::Ifc4x3_rc3::IfcVoidingFeatureTypeEnum::Value > Ifc4x3_rc3::IfcVoidingFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcVoidingFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcVoidingFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcVoidingFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcVoidingFeature::declaration() const { return *IFC4X3_RC3_IfcVoidingFeature_type; }
@@ -23286,7 +23286,7 @@ Ifc4x3_rc3::IfcVoidingFeature::IfcVoidingFeature(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcWall
 boost::optional< ::Ifc4x3_rc3::IfcWallTypeEnum::Value > Ifc4x3_rc3::IfcWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcWall::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcWall::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcWall::declaration() const { return *IFC4X3_RC3_IfcWall_type; }
@@ -23322,7 +23322,7 @@ Ifc4x3_rc3::IfcWallType::IfcWallType(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcWasteTerminal
 boost::optional< ::Ifc4x3_rc3::IfcWasteTerminalTypeEnum::Value > Ifc4x3_rc3::IfcWasteTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcWasteTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWasteTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWasteTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcWasteTerminal::declaration() const { return *IFC4X3_RC3_IfcWasteTerminal_type; }
@@ -23350,15 +23350,15 @@ Ifc4x3_rc3::IfcWaterStratum::IfcWaterStratum(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcWindow
 boost::optional< double > Ifc4x3_rc3::IfcWindow::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindow::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcWindowTypeEnum::Value > Ifc4x3_rc3::IfcWindow::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcWindowTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc3::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWindowTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWindowTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcWindowTypePartitioningEnum::Value > Ifc4x3_rc3::IfcWindow::PartitioningType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc3::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x3_rc3::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWindowTypePartitioningEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x3_rc3::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWindowTypePartitioningEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcWindow::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcWindow::declaration() const { return *IFC4X3_RC3_IfcWindow_type; }
@@ -23368,29 +23368,29 @@ Ifc4x3_rc3::IfcWindow::IfcWindow(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcOwner
 
 // Function implementations for IfcWindowLiningProperties
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::TransomThickness() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::MullionThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::FirstTransomOffset() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::SecondTransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::FirstMullionOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::SecondMullionOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 ::Ifc4x3_rc3::IfcShapeAspect* Ifc4x3_rc3::IfcWindowLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(12)))->as<::Ifc4x3_rc3::IfcShapeAspect>(true); }
 void Ifc4x3_rc3::IfcWindowLiningProperties::setShapeAspectStyle(::Ifc4x3_rc3::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::LiningOffset() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc3::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc3::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcWindowLiningProperties::declaration() const { return *IFC4X3_RC3_IfcWindowLiningProperties_type; }
@@ -23404,9 +23404,9 @@ void Ifc4x3_rc3::IfcWindowPanelProperties::setOperationType(::Ifc4x3_rc3::IfcWin
 ::Ifc4x3_rc3::IfcWindowPanelPositionEnum::Value Ifc4x3_rc3::IfcWindowPanelProperties::PanelPosition() const {  return ::Ifc4x3_rc3::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc3::IfcWindowPanelProperties::setPanelPosition(::Ifc4x3_rc3::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowPanelProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc3::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcWindowPanelProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc3::IfcShapeAspect* Ifc4x3_rc3::IfcWindowPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc3::IfcShapeAspect>(true); }
 void Ifc4x3_rc3::IfcWindowPanelProperties::setShapeAspectStyle(::Ifc4x3_rc3::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -23446,9 +23446,9 @@ void Ifc4x3_rc3::IfcWindowType::setPredefinedType(::Ifc4x3_rc3::IfcWindowTypeEnu
 ::Ifc4x3_rc3::IfcWindowTypePartitioningEnum::Value Ifc4x3_rc3::IfcWindowType::PartitioningType() const {  return ::Ifc4x3_rc3::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc3::IfcWindowType::setPartitioningType(::Ifc4x3_rc3::IfcWindowTypePartitioningEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc3::IfcWindowTypePartitioningEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x3_rc3::IfcWindowType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc3::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc3::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcWindowType::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcWindowType::declaration() const { return *IFC4X3_RC3_IfcWindowType_type; }
@@ -23458,11 +23458,11 @@ Ifc4x3_rc3::IfcWindowType::IfcWindowType(std::string v1_GlobalId, ::Ifc4x3_rc3::
 
 // Function implementations for IfcWorkCalendar
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcWorkTime >::ptr > Ifc4x3_rc3::IfcWorkCalendar::WorkingTimes() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc3::IfcWorkTime >(); }
-void Ifc4x3_rc3::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc3::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcWorkTime >::ptr > Ifc4x3_rc3::IfcWorkCalendar::ExceptionTimes() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc3::IfcWorkTime >(); }
-void Ifc4x3_rc3::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc3::IfcWorkCalendarTypeEnum::Value > Ifc4x3_rc3::IfcWorkCalendar::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcWorkCalendarTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc3::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWorkCalendarTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWorkCalendarTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcWorkCalendar::declaration() const { return *IFC4X3_RC3_IfcWorkCalendar_type; }
@@ -23474,17 +23474,17 @@ Ifc4x3_rc3::IfcWorkCalendar::IfcWorkCalendar(std::string v1_GlobalId, ::Ifc4x3_r
 std::string Ifc4x3_rc3::IfcWorkControl::CreationDate() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcWorkControl::setCreationDate(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPerson >::ptr > Ifc4x3_rc3::IfcWorkControl::Creators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc3::IfcPerson >(); }
-void Ifc4x3_rc3::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x3_rc3::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcWorkControl::Purpose() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcWorkControl::Duration() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc3::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc3::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcWorkControl::TotalFloat() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc3::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc3::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 std::string Ifc4x3_rc3::IfcWorkControl::StartTime() const {  std::string v = *data_->getArgument(11); return v; }
 void Ifc4x3_rc3::IfcWorkControl::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcWorkControl::FinishTime() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc3::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc3::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcWorkControl::declaration() const { return *IFC4X3_RC3_IfcWorkControl_type; }
@@ -23494,7 +23494,7 @@ Ifc4x3_rc3::IfcWorkControl::IfcWorkControl(std::string v1_GlobalId, ::Ifc4x3_rc3
 
 // Function implementations for IfcWorkPlan
 boost::optional< ::Ifc4x3_rc3::IfcWorkPlanTypeEnum::Value > Ifc4x3_rc3::IfcWorkPlan::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcWorkPlanTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc3::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWorkPlanTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWorkPlanTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcWorkPlan::declaration() const { return *IFC4X3_RC3_IfcWorkPlan_type; }
@@ -23504,7 +23504,7 @@ Ifc4x3_rc3::IfcWorkPlan::IfcWorkPlan(std::string v1_GlobalId, ::Ifc4x3_rc3::IfcO
 
 // Function implementations for IfcWorkSchedule
 boost::optional< ::Ifc4x3_rc3::IfcWorkScheduleTypeEnum::Value > Ifc4x3_rc3::IfcWorkSchedule::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc3::IfcWorkScheduleTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc3::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWorkScheduleTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc3::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc3::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc3::IfcWorkScheduleTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcWorkSchedule::declaration() const { return *IFC4X3_RC3_IfcWorkSchedule_type; }
@@ -23516,9 +23516,9 @@ Ifc4x3_rc3::IfcWorkSchedule::IfcWorkSchedule(std::string v1_GlobalId, ::Ifc4x3_r
 ::Ifc4x3_rc3::IfcRecurrencePattern* Ifc4x3_rc3::IfcWorkTime::RecurrencePattern() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc3::IfcRecurrencePattern>(true); }
 void Ifc4x3_rc3::IfcWorkTime::setRecurrencePattern(::Ifc4x3_rc3::IfcRecurrencePattern* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcWorkTime::Start() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc3::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc3::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc3::IfcWorkTime::Finish() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcWorkTime::declaration() const { return *IFC4X3_RC3_IfcWorkTime_type; }
@@ -23536,9 +23536,9 @@ void Ifc4x3_rc3::IfcZShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc3::IfcZShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc3::IfcZShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcZShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc3::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc3::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc3::IfcZShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc3::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc3::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcZShapeProfileDef::declaration() const { return *IFC4X3_RC3_IfcZShapeProfileDef_type; }
@@ -23548,7 +23548,7 @@ Ifc4x3_rc3::IfcZShapeProfileDef::IfcZShapeProfileDef(::Ifc4x3_rc3::IfcProfileTyp
 
 // Function implementations for IfcZone
 boost::optional< std::string > Ifc4x3_rc3::IfcZone::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc3::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc3::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc3::IfcZone::declaration() const { return *IFC4X3_RC3_IfcZone_type; }
diff --git a/src/ifcparse/Ifc4x3_rc4.cpp b/src/ifcparse/Ifc4x3_rc4.cpp
index f946e3f4c4..64058b2c9d 100644
--- a/src/ifcparse/Ifc4x3_rc4.cpp
+++ b/src/ifcparse/Ifc4x3_rc4.cpp
@@ -13148,11 +13148,11 @@ Ifc4x3_rc4::IfcWarpingMomentMeasure::operator double() const { return *data_->ge
 
 // Function implementations for IfcActionRequest
 boost::optional< ::Ifc4x3_rc4::IfcActionRequestTypeEnum::Value > Ifc4x3_rc4::IfcActionRequest::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcActionRequestTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc4::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcActionRequestTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcActionRequest::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcActionRequestTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcActionRequestTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcActionRequest::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcActionRequest::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcActionRequest::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcActionRequest::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcActionRequest::declaration() const { return *IFC4X3_RC4_IfcActionRequest_type; }
@@ -13175,9 +13175,9 @@ Ifc4x3_rc4::IfcActor::IfcActor(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHi
 ::Ifc4x3_rc4::IfcRoleEnum::Value Ifc4x3_rc4::IfcActorRole::Role() const {  return ::Ifc4x3_rc4::IfcRoleEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc4::IfcActorRole::setRole(::Ifc4x3_rc4::IfcRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcRoleEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcActorRole::UserDefinedRole() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcActorRole::setUserDefinedRole(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcActorRole::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcActorRole::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc4::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc4::IfcActorRole::HasExternalReference() const { return data_->getInverse(IFC4X3_RC4_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -13188,7 +13188,7 @@ Ifc4x3_rc4::IfcActorRole::IfcActorRole(::Ifc4x3_rc4::IfcRoleEnum::Value v1_Role,
 
 // Function implementations for IfcActuator
 boost::optional< ::Ifc4x3_rc4::IfcActuatorTypeEnum::Value > Ifc4x3_rc4::IfcActuator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcActuatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcActuatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcActuator::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcActuatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcActuatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcActuator::declaration() const { return *IFC4X3_RC4_IfcActuator_type; }
@@ -13208,11 +13208,11 @@ Ifc4x3_rc4::IfcActuatorType::IfcActuatorType(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcAddress
 boost::optional< ::Ifc4x3_rc4::IfcAddressTypeEnum::Value > Ifc4x3_rc4::IfcAddress::Purpose() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcAddressTypeEnum::FromString(*data_->getArgument(0)); }
-void Ifc4x3_rc4::IfcAddress::setPurpose(boost::optional< ::Ifc4x3_rc4::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAddressTypeEnum::ToString(*v)));data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcAddress::setPurpose(boost::optional< ::Ifc4x3_rc4::IfcAddressTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAddressTypeEnum::ToString(*v)));}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcAddress::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcAddress::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcAddress::UserDefinedPurpose() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcAddress::setUserDefinedPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc4::IfcPerson::list::ptr Ifc4x3_rc4::IfcAddress::OfPerson() const { return data_->getInverse(IFC4X3_RC4_IfcPerson_type, 7)->as<IfcPerson>(); }
 ::Ifc4x3_rc4::IfcOrganization::list::ptr Ifc4x3_rc4::IfcAddress::OfOrganization() const { return data_->getInverse(IFC4X3_RC4_IfcOrganization_type, 4)->as<IfcOrganization>(); }
@@ -13250,7 +13250,7 @@ Ifc4x3_rc4::IfcAdvancedFace::IfcAdvancedFace(aggregate_of< ::Ifc4x3_rc4::IfcFace
 
 // Function implementations for IfcAirTerminal
 boost::optional< ::Ifc4x3_rc4::IfcAirTerminalTypeEnum::Value > Ifc4x3_rc4::IfcAirTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcAirTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAirTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcAirTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAirTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAirTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcAirTerminal::declaration() const { return *IFC4X3_RC4_IfcAirTerminal_type; }
@@ -13260,7 +13260,7 @@ Ifc4x3_rc4::IfcAirTerminal::IfcAirTerminal(std::string v1_GlobalId, ::Ifc4x3_rc4
 
 // Function implementations for IfcAirTerminalBox
 boost::optional< ::Ifc4x3_rc4::IfcAirTerminalBoxTypeEnum::Value > Ifc4x3_rc4::IfcAirTerminalBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcAirTerminalBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAirTerminalBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcAirTerminalBox::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAirTerminalBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAirTerminalBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcAirTerminalBox::declaration() const { return *IFC4X3_RC4_IfcAirTerminalBox_type; }
@@ -13290,7 +13290,7 @@ Ifc4x3_rc4::IfcAirTerminalType::IfcAirTerminalType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcAirToAirHeatRecovery
 boost::optional< ::Ifc4x3_rc4::IfcAirToAirHeatRecoveryTypeEnum::Value > Ifc4x3_rc4::IfcAirToAirHeatRecovery::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcAirToAirHeatRecoveryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcAirToAirHeatRecovery::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAirToAirHeatRecoveryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAirToAirHeatRecoveryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcAirToAirHeatRecovery::declaration() const { return *IFC4X3_RC4_IfcAirToAirHeatRecovery_type; }
@@ -13310,7 +13310,7 @@ Ifc4x3_rc4::IfcAirToAirHeatRecoveryType::IfcAirToAirHeatRecoveryType(std::string
 
 // Function implementations for IfcAlarm
 boost::optional< ::Ifc4x3_rc4::IfcAlarmTypeEnum::Value > Ifc4x3_rc4::IfcAlarm::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcAlarmTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAlarmTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcAlarm::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAlarmTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAlarmTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcAlarm::declaration() const { return *IFC4X3_RC4_IfcAlarm_type; }
@@ -13330,7 +13330,7 @@ Ifc4x3_rc4::IfcAlarmType::IfcAlarmType(std::string v1_GlobalId, ::Ifc4x3_rc4::If
 
 // Function implementations for IfcAlignment
 boost::optional< ::Ifc4x3_rc4::IfcAlignmentTypeEnum::Value > Ifc4x3_rc4::IfcAlignment::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcAlignmentTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc4::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAlignmentTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcAlignment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAlignmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAlignmentTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcAlignment::declaration() const { return *IFC4X3_RC4_IfcAlignment_type; }
@@ -13356,11 +13356,11 @@ void Ifc4x3_rc4::IfcAlignmentCantSegment::setHorizontalLength(double v) { {IfcWr
 double Ifc4x3_rc4::IfcAlignmentCantSegment::StartCantLeft() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc4::IfcAlignmentCantSegment::setStartCantLeft(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAlignmentCantSegment::EndCantLeft() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcAlignmentCantSegment::setEndCantLeft(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcAlignmentCantSegment::setEndCantLeft(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 double Ifc4x3_rc4::IfcAlignmentCantSegment::StartCantRight() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcAlignmentCantSegment::setStartCantRight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAlignmentCantSegment::EndCantRight() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcAlignmentCantSegment::setEndCantRight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcAlignmentCantSegment::setEndCantRight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcAlignmentCantSegmentTypeEnum::Value Ifc4x3_rc4::IfcAlignmentCantSegment::PredefinedType() const {  return ::Ifc4x3_rc4::IfcAlignmentCantSegmentTypeEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc4::IfcAlignmentCantSegment::setPredefinedType(::Ifc4x3_rc4::IfcAlignmentCantSegmentTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcAlignmentCantSegmentTypeEnum::ToString(v)));data_->setArgument(8,attr);} }
 
@@ -13390,7 +13390,7 @@ void Ifc4x3_rc4::IfcAlignmentHorizontalSegment::setEndRadiusOfCurvature(double v
 double Ifc4x3_rc4::IfcAlignmentHorizontalSegment::SegmentLength() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcAlignmentHorizontalSegment::setSegmentLength(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAlignmentHorizontalSegment::GravityCenterLineHeight() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcAlignmentHorizontalSegment::setGravityCenterLineHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcAlignmentHorizontalSegment::setGravityCenterLineHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcAlignmentHorizontalSegmentTypeEnum::Value Ifc4x3_rc4::IfcAlignmentHorizontalSegment::PredefinedType() const {  return ::Ifc4x3_rc4::IfcAlignmentHorizontalSegmentTypeEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc4::IfcAlignmentHorizontalSegment::setPredefinedType(::Ifc4x3_rc4::IfcAlignmentHorizontalSegmentTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcAlignmentHorizontalSegmentTypeEnum::ToString(v)));data_->setArgument(8,attr);} }
 
@@ -13402,9 +13402,9 @@ Ifc4x3_rc4::IfcAlignmentHorizontalSegment::IfcAlignmentHorizontalSegment(boost::
 
 // Function implementations for IfcAlignmentParameterSegment
 boost::optional< std::string > Ifc4x3_rc4::IfcAlignmentParameterSegment::StartTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcAlignmentParameterSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcAlignmentParameterSegment::setStartTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcAlignmentParameterSegment::EndTag() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcAlignmentParameterSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcAlignmentParameterSegment::setEndTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcAlignmentParameterSegment::declaration() const { return *IFC4X3_RC4_IfcAlignmentParameterSegment_type; }
@@ -13442,7 +13442,7 @@ void Ifc4x3_rc4::IfcAlignmentVerticalSegment::setStartGradient(double v) { {IfcW
 double Ifc4x3_rc4::IfcAlignmentVerticalSegment::EndGradient() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcAlignmentVerticalSegment::setEndGradient(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAlignmentVerticalSegment::RadiusOfCurvature() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcAlignmentVerticalSegment::setRadiusOfCurvature(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcAlignmentVerticalSegment::setRadiusOfCurvature(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcAlignmentVerticalSegmentTypeEnum::Value Ifc4x3_rc4::IfcAlignmentVerticalSegment::PredefinedType() const {  return ::Ifc4x3_rc4::IfcAlignmentVerticalSegmentTypeEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc4::IfcAlignmentVerticalSegment::setPredefinedType(::Ifc4x3_rc4::IfcAlignmentVerticalSegmentTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcAlignmentVerticalSegmentTypeEnum::ToString(v)));data_->setArgument(8,attr);} }
 
@@ -13454,7 +13454,7 @@ Ifc4x3_rc4::IfcAlignmentVerticalSegment::IfcAlignmentVerticalSegment(boost::opti
 
 // Function implementations for IfcAnnotation
 boost::optional< ::Ifc4x3_rc4::IfcAnnotationTypeEnum::Value > Ifc4x3_rc4::IfcAnnotation::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcAnnotationTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc4::IfcAnnotation::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAnnotationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAnnotationTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcAnnotation::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAnnotationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAnnotationTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc4::IfcRelContainedInSpatialStructure::list::ptr Ifc4x3_rc4::IfcAnnotation::ContainedInStructure() const { return data_->getInverse(IFC4X3_RC4_IfcRelContainedInSpatialStructure_type, 4)->as<IfcRelContainedInSpatialStructure>(); }
 
@@ -13467,7 +13467,7 @@ Ifc4x3_rc4::IfcAnnotation::IfcAnnotation(std::string v1_GlobalId, ::Ifc4x3_rc4::
 ::Ifc4x3_rc4::IfcCurve* Ifc4x3_rc4::IfcAnnotationFillArea::OuterBoundary() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc4::IfcCurve>(true); }
 void Ifc4x3_rc4::IfcAnnotationFillArea::setOuterBoundary(::Ifc4x3_rc4::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcCurve >::ptr > Ifc4x3_rc4::IfcAnnotationFillArea::InnerBoundaries() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc4::IfcCurve >(); }
-void Ifc4x3_rc4::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcAnnotationFillArea::setInnerBoundaries(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcCurve >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcAnnotationFillArea::declaration() const { return *IFC4X3_RC4_IfcAnnotationFillArea_type; }
@@ -13493,25 +13493,25 @@ Ifc4x3_rc4::IfcApplication::IfcApplication(::Ifc4x3_rc4::IfcOrganization* v1_App
 
 // Function implementations for IfcAppliedValue
 boost::optional< std::string > Ifc4x3_rc4::IfcAppliedValue::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcAppliedValue::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcAppliedValue::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcAppliedValue::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc4::IfcAppliedValueSelect* Ifc4x3_rc4::IfcAppliedValue::AppliedValue() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc4::IfcAppliedValueSelect>(true); }
 void Ifc4x3_rc4::IfcAppliedValue::setAppliedValue(::Ifc4x3_rc4::IfcAppliedValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcMeasureWithUnit* Ifc4x3_rc4::IfcAppliedValue::UnitBasis() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcMeasureWithUnit>(true); }
 void Ifc4x3_rc4::IfcAppliedValue::setUnitBasis(::Ifc4x3_rc4::IfcMeasureWithUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcAppliedValue::ApplicableDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcAppliedValue::setApplicableDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcAppliedValue::FixedUntilDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcAppliedValue::setFixedUntilDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcAppliedValue::Category() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcAppliedValue::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcAppliedValue::Condition() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcAppliedValue::setCondition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcArithmeticOperatorEnum::Value > Ifc4x3_rc4::IfcAppliedValue::ArithmeticOperator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcArithmeticOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x3_rc4::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcArithmeticOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcAppliedValue::setArithmeticOperator(boost::optional< ::Ifc4x3_rc4::IfcArithmeticOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcArithmeticOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAppliedValue >::ptr > Ifc4x3_rc4::IfcAppliedValue::Components() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc4::IfcAppliedValue >(); }
-void Ifc4x3_rc4::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcAppliedValue::setComponents(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 
 ::Ifc4x3_rc4::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc4::IfcAppliedValue::HasExternalReference() const { return data_->getInverse(IFC4X3_RC4_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 
@@ -13522,19 +13522,19 @@ Ifc4x3_rc4::IfcAppliedValue::IfcAppliedValue(boost::optional< std::string > v1_N
 
 // Function implementations for IfcApproval
 boost::optional< std::string > Ifc4x3_rc4::IfcApproval::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcApproval::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcApproval::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcApproval::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcApproval::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcApproval::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcApproval::TimeOfApproval() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcApproval::setTimeOfApproval(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcApproval::Status() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcApproval::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcApproval::Level() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcApproval::setLevel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcApproval::Qualifier() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcApproval::setQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc4::IfcActorSelect* Ifc4x3_rc4::IfcApproval::RequestingApproval() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc4::IfcActorSelect>(true); }
 void Ifc4x3_rc4::IfcApproval::setRequestingApproval(::Ifc4x3_rc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcActorSelect* Ifc4x3_rc4::IfcApproval::GivingApproval() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc4::IfcActorSelect>(true); }
@@ -13595,7 +13595,7 @@ Ifc4x3_rc4::IfcArbitraryProfileDefWithVoids::IfcArbitraryProfileDefWithVoids(::I
 
 // Function implementations for IfcAsset
 boost::optional< std::string > Ifc4x3_rc4::IfcAsset::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcAsset::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc4::IfcCostValue* Ifc4x3_rc4::IfcAsset::OriginalValue() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcCostValue>(true); }
 void Ifc4x3_rc4::IfcAsset::setOriginalValue(::Ifc4x3_rc4::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 ::Ifc4x3_rc4::IfcCostValue* Ifc4x3_rc4::IfcAsset::CurrentValue() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc4::IfcCostValue>(true); }
@@ -13609,7 +13609,7 @@ void Ifc4x3_rc4::IfcAsset::setUser(::Ifc4x3_rc4::IfcActorSelect* v) { {IfcWrite:
 ::Ifc4x3_rc4::IfcPerson* Ifc4x3_rc4::IfcAsset::ResponsiblePerson() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc4::IfcPerson>(true); }
 void Ifc4x3_rc4::IfcAsset::setResponsiblePerson(::Ifc4x3_rc4::IfcPerson* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcAsset::IncorporationDate() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcAsset::setIncorporationDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x3_rc4::IfcCostValue* Ifc4x3_rc4::IfcAsset::DepreciatedValue() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x3_rc4::IfcCostValue>(true); }
 void Ifc4x3_rc4::IfcAsset::setDepreciatedValue(::Ifc4x3_rc4::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -13629,21 +13629,21 @@ void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setWebThickness(double v) { {Ifc
 double Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::BottomFlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::BottomFlangeFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 double Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::TopFlangeWidth() const {  double v = *data_->getArgument(8); return v; }
 void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setTopFlangeWidth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::TopFlangeThickness() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setTopFlangeThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::TopFlangeFilletRadius() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setTopFlangeFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::BottomFlangeEdgeRadius() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::BottomFlangeSlope() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setBottomFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::TopFlangeEdgeRadius() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setTopFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::TopFlangeSlope() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::setTopFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::declaration() const { return *IFC4X3_RC4_IfcAsymmetricIShapeProfileDef_type; }
@@ -13653,7 +13653,7 @@ Ifc4x3_rc4::IfcAsymmetricIShapeProfileDef::IfcAsymmetricIShapeProfileDef(::Ifc4x
 
 // Function implementations for IfcAudioVisualAppliance
 boost::optional< ::Ifc4x3_rc4::IfcAudioVisualApplianceTypeEnum::Value > Ifc4x3_rc4::IfcAudioVisualAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcAudioVisualApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAudioVisualApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcAudioVisualAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcAudioVisualApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAudioVisualApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcAudioVisualAppliance::declaration() const { return *IFC4X3_RC4_IfcAudioVisualAppliance_type; }
@@ -13789,7 +13789,7 @@ Ifc4x3_rc4::IfcBSplineSurfaceWithKnots::IfcBSplineSurfaceWithKnots(int v1_UDegre
 
 // Function implementations for IfcBeam
 boost::optional< ::Ifc4x3_rc4::IfcBeamTypeEnum::Value > Ifc4x3_rc4::IfcBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBeam::declaration() const { return *IFC4X3_RC4_IfcBeam_type; }
@@ -13817,7 +13817,7 @@ Ifc4x3_rc4::IfcBeamType::IfcBeamType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcBearing
 boost::optional< ::Ifc4x3_rc4::IfcBearingTypeEnum::Value > Ifc4x3_rc4::IfcBearing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcBearingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcBearing::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBearingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBearingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcBearing::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBearingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBearingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBearing::declaration() const { return *IFC4X3_RC4_IfcBearing_type; }
@@ -13863,7 +13863,7 @@ Ifc4x3_rc4::IfcBlock::IfcBlock(::Ifc4x3_rc4::IfcAxis2Placement3D* v1_Position, d
 
 // Function implementations for IfcBoiler
 boost::optional< ::Ifc4x3_rc4::IfcBoilerTypeEnum::Value > Ifc4x3_rc4::IfcBoiler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcBoilerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBoilerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcBoiler::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBoilerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBoilerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBoiler::declaration() const { return *IFC4X3_RC4_IfcBoiler_type; }
@@ -13913,7 +13913,7 @@ Ifc4x3_rc4::IfcBorehole::IfcBorehole(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcBoundaryCondition
 boost::optional< std::string > Ifc4x3_rc4::IfcBoundaryCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcBoundaryCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBoundaryCondition::declaration() const { return *IFC4X3_RC4_IfcBoundaryCondition_type; }
@@ -14037,7 +14037,7 @@ Ifc4x3_rc4::IfcBoxedHalfSpace::IfcBoxedHalfSpace(::Ifc4x3_rc4::IfcSurface* v1_Ba
 
 // Function implementations for IfcBridge
 boost::optional< ::Ifc4x3_rc4::IfcBridgeTypeEnum::Value > Ifc4x3_rc4::IfcBridge::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcBridgeTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcBridge::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBridgeTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBridgeTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcBridge::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBridgeTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBridgeTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBridge::declaration() const { return *IFC4X3_RC4_IfcBridge_type; }
@@ -14047,9 +14047,9 @@ Ifc4x3_rc4::IfcBridge::IfcBridge(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwner
 
 // Function implementations for IfcBuilding
 boost::optional< double > Ifc4x3_rc4::IfcBuilding::ElevationOfRefHeight() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcBuilding::setElevationOfRefHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcBuilding::ElevationOfTerrain() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcBuilding::setElevationOfTerrain(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc4::IfcPostalAddress* Ifc4x3_rc4::IfcBuilding::BuildingAddress() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc4::IfcPostalAddress>(true); }
 void Ifc4x3_rc4::IfcBuilding::setBuildingAddress(::Ifc4x3_rc4::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 
@@ -14061,7 +14061,7 @@ Ifc4x3_rc4::IfcBuilding::IfcBuilding(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcBuildingElementPart
 boost::optional< ::Ifc4x3_rc4::IfcBuildingElementPartTypeEnum::Value > Ifc4x3_rc4::IfcBuildingElementPart::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcBuildingElementPartTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBuildingElementPartTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcBuildingElementPart::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBuildingElementPartTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBuildingElementPartTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBuildingElementPart::declaration() const { return *IFC4X3_RC4_IfcBuildingElementPart_type; }
@@ -14081,7 +14081,7 @@ Ifc4x3_rc4::IfcBuildingElementPartType::IfcBuildingElementPartType(std::string v
 
 // Function implementations for IfcBuildingElementProxy
 boost::optional< ::Ifc4x3_rc4::IfcBuildingElementProxyTypeEnum::Value > Ifc4x3_rc4::IfcBuildingElementProxy::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcBuildingElementProxyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBuildingElementProxyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcBuildingElementProxy::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBuildingElementProxyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBuildingElementProxyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBuildingElementProxy::declaration() const { return *IFC4X3_RC4_IfcBuildingElementProxy_type; }
@@ -14101,7 +14101,7 @@ Ifc4x3_rc4::IfcBuildingElementProxyType::IfcBuildingElementProxyType(std::string
 
 // Function implementations for IfcBuildingStorey
 boost::optional< double > Ifc4x3_rc4::IfcBuildingStorey::Elevation() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcBuildingStorey::setElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBuildingStorey::declaration() const { return *IFC4X3_RC4_IfcBuildingStorey_type; }
@@ -14111,9 +14111,9 @@ Ifc4x3_rc4::IfcBuildingStorey::IfcBuildingStorey(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcBuildingSystem
 boost::optional< ::Ifc4x3_rc4::IfcBuildingSystemTypeEnum::Value > Ifc4x3_rc4::IfcBuildingSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcBuildingSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc4::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBuildingSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcBuildingSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBuildingSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBuildingSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcBuildingSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcBuildingSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBuildingSystem::declaration() const { return *IFC4X3_RC4_IfcBuildingSystem_type; }
@@ -14139,9 +14139,9 @@ Ifc4x3_rc4::IfcBuiltElementType::IfcBuiltElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcBuiltSystem
 boost::optional< ::Ifc4x3_rc4::IfcBuiltSystemTypeEnum::Value > Ifc4x3_rc4::IfcBuiltSystem::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcBuiltSystemTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc4::IfcBuiltSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBuiltSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBuiltSystemTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcBuiltSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBuiltSystemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBuiltSystemTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcBuiltSystem::LongName() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcBuiltSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcBuiltSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBuiltSystem::declaration() const { return *IFC4X3_RC4_IfcBuiltSystem_type; }
@@ -14151,7 +14151,7 @@ Ifc4x3_rc4::IfcBuiltSystem::IfcBuiltSystem(std::string v1_GlobalId, ::Ifc4x3_rc4
 
 // Function implementations for IfcBurner
 boost::optional< ::Ifc4x3_rc4::IfcBurnerTypeEnum::Value > Ifc4x3_rc4::IfcBurner::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcBurnerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBurnerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcBurner::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcBurnerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcBurnerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcBurner::declaration() const { return *IFC4X3_RC4_IfcBurner_type; }
@@ -14179,7 +14179,7 @@ void Ifc4x3_rc4::IfcCShapeProfileDef::setWallThickness(double v) { {IfcWrite::If
 double Ifc4x3_rc4::IfcCShapeProfileDef::Girth() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcCShapeProfileDef::setGirth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcCShapeProfileDef::InternalFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcCShapeProfileDef::setInternalFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCShapeProfileDef::declaration() const { return *IFC4X3_RC4_IfcCShapeProfileDef_type; }
@@ -14189,7 +14189,7 @@ Ifc4x3_rc4::IfcCShapeProfileDef::IfcCShapeProfileDef(::Ifc4x3_rc4::IfcProfileTyp
 
 // Function implementations for IfcCableCarrierFitting
 boost::optional< ::Ifc4x3_rc4::IfcCableCarrierFittingTypeEnum::Value > Ifc4x3_rc4::IfcCableCarrierFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCableCarrierFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCableCarrierFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCableCarrierFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCableCarrierFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCableCarrierFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCableCarrierFitting::declaration() const { return *IFC4X3_RC4_IfcCableCarrierFitting_type; }
@@ -14209,7 +14209,7 @@ Ifc4x3_rc4::IfcCableCarrierFittingType::IfcCableCarrierFittingType(std::string v
 
 // Function implementations for IfcCableCarrierSegment
 boost::optional< ::Ifc4x3_rc4::IfcCableCarrierSegmentTypeEnum::Value > Ifc4x3_rc4::IfcCableCarrierSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCableCarrierSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCableCarrierSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCableCarrierSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCableCarrierSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCableCarrierSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCableCarrierSegment::declaration() const { return *IFC4X3_RC4_IfcCableCarrierSegment_type; }
@@ -14229,7 +14229,7 @@ Ifc4x3_rc4::IfcCableCarrierSegmentType::IfcCableCarrierSegmentType(std::string v
 
 // Function implementations for IfcCableFitting
 boost::optional< ::Ifc4x3_rc4::IfcCableFittingTypeEnum::Value > Ifc4x3_rc4::IfcCableFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCableFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCableFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCableFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCableFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCableFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCableFitting::declaration() const { return *IFC4X3_RC4_IfcCableFitting_type; }
@@ -14249,7 +14249,7 @@ Ifc4x3_rc4::IfcCableFittingType::IfcCableFittingType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcCableSegment
 boost::optional< ::Ifc4x3_rc4::IfcCableSegmentTypeEnum::Value > Ifc4x3_rc4::IfcCableSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCableSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCableSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCableSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCableSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCableSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCableSegment::declaration() const { return *IFC4X3_RC4_IfcCableSegment_type; }
@@ -14269,7 +14269,7 @@ Ifc4x3_rc4::IfcCableSegmentType::IfcCableSegmentType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcCaissonFoundation
 boost::optional< ::Ifc4x3_rc4::IfcCaissonFoundationTypeEnum::Value > Ifc4x3_rc4::IfcCaissonFoundation::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCaissonFoundationTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCaissonFoundation::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCaissonFoundationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCaissonFoundationTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCaissonFoundation::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCaissonFoundationTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCaissonFoundationTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCaissonFoundation::declaration() const { return *IFC4X3_RC4_IfcCaissonFoundation_type; }
@@ -14309,7 +14309,7 @@ Ifc4x3_rc4::IfcCartesianPointList::IfcCartesianPointList() : IfcGeometricReprese
 std::vector< std::vector< double > > Ifc4x3_rc4::IfcCartesianPointList2D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc4::IfcCartesianPointList2D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcCartesianPointList2D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcCartesianPointList2D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCartesianPointList2D::declaration() const { return *IFC4X3_RC4_IfcCartesianPointList2D_type; }
@@ -14321,7 +14321,7 @@ Ifc4x3_rc4::IfcCartesianPointList2D::IfcCartesianPointList2D(std::vector< std::v
 std::vector< std::vector< double > > Ifc4x3_rc4::IfcCartesianPointList3D::CoordList() const {  std::vector< std::vector< double > > v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc4::IfcCartesianPointList3D::setCoordList(std::vector< std::vector< double > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcCartesianPointList3D::TagList() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcCartesianPointList3D::setTagList(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCartesianPointList3D::declaration() const { return *IFC4X3_RC4_IfcCartesianPointList3D_type; }
@@ -14337,7 +14337,7 @@ void Ifc4x3_rc4::IfcCartesianTransformationOperator::setAxis2(::Ifc4x3_rc4::IfcD
 ::Ifc4x3_rc4::IfcCartesianPoint* Ifc4x3_rc4::IfcCartesianTransformationOperator::LocalOrigin() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc4::IfcCartesianPoint>(true); }
 void Ifc4x3_rc4::IfcCartesianTransformationOperator::setLocalOrigin(::Ifc4x3_rc4::IfcCartesianPoint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcCartesianTransformationOperator::Scale() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcCartesianTransformationOperator::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCartesianTransformationOperator::declaration() const { return *IFC4X3_RC4_IfcCartesianTransformationOperator_type; }
@@ -14355,7 +14355,7 @@ Ifc4x3_rc4::IfcCartesianTransformationOperator2D::IfcCartesianTransformationOper
 
 // Function implementations for IfcCartesianTransformationOperator2DnonUniform
 boost::optional< double > Ifc4x3_rc4::IfcCartesianTransformationOperator2DnonUniform::Scale2() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcCartesianTransformationOperator2DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCartesianTransformationOperator2DnonUniform::declaration() const { return *IFC4X3_RC4_IfcCartesianTransformationOperator2DnonUniform_type; }
@@ -14375,9 +14375,9 @@ Ifc4x3_rc4::IfcCartesianTransformationOperator3D::IfcCartesianTransformationOper
 
 // Function implementations for IfcCartesianTransformationOperator3DnonUniform
 boost::optional< double > Ifc4x3_rc4::IfcCartesianTransformationOperator3DnonUniform::Scale2() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcCartesianTransformationOperator3DnonUniform::setScale2(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcCartesianTransformationOperator3DnonUniform::Scale3() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcCartesianTransformationOperator3DnonUniform::setScale3(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCartesianTransformationOperator3DnonUniform::declaration() const { return *IFC4X3_RC4_IfcCartesianTransformationOperator3DnonUniform_type; }
@@ -14397,7 +14397,7 @@ Ifc4x3_rc4::IfcCenterLineProfileDef::IfcCenterLineProfileDef(::Ifc4x3_rc4::IfcPr
 
 // Function implementations for IfcChiller
 boost::optional< ::Ifc4x3_rc4::IfcChillerTypeEnum::Value > Ifc4x3_rc4::IfcChiller::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcChillerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcChillerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcChiller::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcChillerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcChillerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcChiller::declaration() const { return *IFC4X3_RC4_IfcChiller_type; }
@@ -14417,7 +14417,7 @@ Ifc4x3_rc4::IfcChillerType::IfcChillerType(std::string v1_GlobalId, ::Ifc4x3_rc4
 
 // Function implementations for IfcChimney
 boost::optional< ::Ifc4x3_rc4::IfcChimneyTypeEnum::Value > Ifc4x3_rc4::IfcChimney::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcChimneyTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcChimneyTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcChimney::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcChimneyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcChimneyTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcChimney::declaration() const { return *IFC4X3_RC4_IfcChimney_type; }
@@ -14483,19 +14483,19 @@ Ifc4x3_rc4::IfcCivilElementType::IfcCivilElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcClassification
 boost::optional< std::string > Ifc4x3_rc4::IfcClassification::Source() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcClassification::setSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcClassification::Edition() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcClassification::setEdition(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcClassification::EditionDate() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcClassification::setEditionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::string Ifc4x3_rc4::IfcClassification::Name() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcClassification::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcClassification::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcClassification::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcClassification::Location() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcClassification::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcClassification::ReferenceTokens() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcClassification::setReferenceTokens(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc4::IfcRelAssociatesClassification::list::ptr Ifc4x3_rc4::IfcClassification::ClassificationForObjects() const { return data_->getInverse(IFC4X3_RC4_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x3_rc4::IfcClassificationReference::list::ptr Ifc4x3_rc4::IfcClassification::HasReferences() const { return data_->getInverse(IFC4X3_RC4_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -14509,9 +14509,9 @@ Ifc4x3_rc4::IfcClassification::IfcClassification(boost::optional< std::string >
 ::Ifc4x3_rc4::IfcClassificationReferenceSelect* Ifc4x3_rc4::IfcClassificationReference::ReferencedSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcClassificationReferenceSelect>(true); }
 void Ifc4x3_rc4::IfcClassificationReference::setReferencedSource(::Ifc4x3_rc4::IfcClassificationReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcClassificationReference::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcClassificationReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcClassificationReference::Sort() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcClassificationReference::setSort(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc4::IfcRelAssociatesClassification::list::ptr Ifc4x3_rc4::IfcClassificationReference::ClassificationRefForObjects() const { return data_->getInverse(IFC4X3_RC4_IfcRelAssociatesClassification_type, 5)->as<IfcRelAssociatesClassification>(); }
 ::Ifc4x3_rc4::IfcClassificationReference::list::ptr Ifc4x3_rc4::IfcClassificationReference::HasReferences() const { return data_->getInverse(IFC4X3_RC4_IfcClassificationReference_type, 3)->as<IfcClassificationReference>(); }
@@ -14541,7 +14541,7 @@ Ifc4x3_rc4::IfcClothoid::IfcClothoid(::Ifc4x3_rc4::IfcAxis2Placement* v1_Positio
 
 // Function implementations for IfcCoil
 boost::optional< ::Ifc4x3_rc4::IfcCoilTypeEnum::Value > Ifc4x3_rc4::IfcCoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCoil::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCoil::declaration() const { return *IFC4X3_RC4_IfcCoil_type; }
@@ -14585,7 +14585,7 @@ Ifc4x3_rc4::IfcColourRgbList::IfcColourRgbList(std::vector< std::vector< double
 
 // Function implementations for IfcColourSpecification
 boost::optional< std::string > Ifc4x3_rc4::IfcColourSpecification::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcColourSpecification::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcColourSpecification::declaration() const { return *IFC4X3_RC4_IfcColourSpecification_type; }
@@ -14595,7 +14595,7 @@ Ifc4x3_rc4::IfcColourSpecification::IfcColourSpecification(boost::optional< std:
 
 // Function implementations for IfcColumn
 boost::optional< ::Ifc4x3_rc4::IfcColumnTypeEnum::Value > Ifc4x3_rc4::IfcColumn::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcColumnTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcColumnTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcColumn::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcColumnTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcColumnTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcColumn::declaration() const { return *IFC4X3_RC4_IfcColumn_type; }
@@ -14623,7 +14623,7 @@ Ifc4x3_rc4::IfcColumnType::IfcColumnType(std::string v1_GlobalId, ::Ifc4x3_rc4::
 
 // Function implementations for IfcCommunicationsAppliance
 boost::optional< ::Ifc4x3_rc4::IfcCommunicationsApplianceTypeEnum::Value > Ifc4x3_rc4::IfcCommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCommunicationsAppliance::declaration() const { return *IFC4X3_RC4_IfcCommunicationsAppliance_type; }
@@ -14655,11 +14655,11 @@ Ifc4x3_rc4::IfcComplexProperty::IfcComplexProperty(std::string v1_Name, boost::o
 
 // Function implementations for IfcComplexPropertyTemplate
 boost::optional< std::string > Ifc4x3_rc4::IfcComplexPropertyTemplate::UsageName() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcComplexPropertyTemplate::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcComplexPropertyTemplateTypeEnum::Value > Ifc4x3_rc4::IfcComplexPropertyTemplate::TemplateType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcComplexPropertyTemplateTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc4::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc4::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcComplexPropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc4::IfcComplexPropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcComplexPropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPropertyTemplate >::ptr > Ifc4x3_rc4::IfcComplexPropertyTemplate::HasPropertyTemplates() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc4::IfcPropertyTemplate >(); }
-void Ifc4x3_rc4::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcComplexPropertyTemplate::setHasPropertyTemplates(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPropertyTemplate >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcComplexPropertyTemplate::declaration() const { return *IFC4X3_RC4_IfcComplexPropertyTemplate_type; }
@@ -14703,7 +14703,7 @@ Ifc4x3_rc4::IfcCompositeCurveSegment::IfcCompositeCurveSegment(::Ifc4x3_rc4::Ifc
 aggregate_of< ::Ifc4x3_rc4::IfcProfileDef >::ptr Ifc4x3_rc4::IfcCompositeProfileDef::Profiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc4::IfcProfileDef >(); }
 void Ifc4x3_rc4::IfcCompositeProfileDef::setProfiles(aggregate_of< ::Ifc4x3_rc4::IfcProfileDef >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcCompositeProfileDef::Label() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcCompositeProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCompositeProfileDef::declaration() const { return *IFC4X3_RC4_IfcCompositeProfileDef_type; }
@@ -14713,7 +14713,7 @@ Ifc4x3_rc4::IfcCompositeProfileDef::IfcCompositeProfileDef(::Ifc4x3_rc4::IfcProf
 
 // Function implementations for IfcCompressor
 boost::optional< ::Ifc4x3_rc4::IfcCompressorTypeEnum::Value > Ifc4x3_rc4::IfcCompressor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCompressorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCompressorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCompressor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCompressorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCompressorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCompressor::declaration() const { return *IFC4X3_RC4_IfcCompressor_type; }
@@ -14733,7 +14733,7 @@ Ifc4x3_rc4::IfcCompressorType::IfcCompressorType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCondenser
 boost::optional< ::Ifc4x3_rc4::IfcCondenserTypeEnum::Value > Ifc4x3_rc4::IfcCondenser::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCondenserTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCondenserTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCondenser::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCondenserTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCondenserTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCondenser::declaration() const { return *IFC4X3_RC4_IfcCondenser_type; }
@@ -14793,11 +14793,11 @@ Ifc4x3_rc4::IfcConnectionGeometry::IfcConnectionGeometry() : IfcUtil::IfcBaseEnt
 
 // Function implementations for IfcConnectionPointEccentricity
 boost::optional< double > Ifc4x3_rc4::IfcConnectionPointEccentricity::EccentricityInX() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcConnectionPointEccentricity::setEccentricityInX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcConnectionPointEccentricity::EccentricityInY() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcConnectionPointEccentricity::setEccentricityInY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcConnectionPointEccentricity::EccentricityInZ() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcConnectionPointEccentricity::setEccentricityInZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcConnectionPointEccentricity::declaration() const { return *IFC4X3_RC4_IfcConnectionPointEccentricity_type; }
@@ -14845,17 +14845,17 @@ Ifc4x3_rc4::IfcConnectionVolumeGeometry::IfcConnectionVolumeGeometry(::Ifc4x3_rc
 std::string Ifc4x3_rc4::IfcConstraint::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc4::IfcConstraint::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcConstraint::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcConstraint::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc4::IfcConstraintEnum::Value Ifc4x3_rc4::IfcConstraint::ConstraintGrade() const {  return ::Ifc4x3_rc4::IfcConstraintEnum::FromString(*data_->getArgument(2)); }
 void Ifc4x3_rc4::IfcConstraint::setConstraintGrade(::Ifc4x3_rc4::IfcConstraintEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcConstraintEnum::ToString(v)));data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcConstraint::ConstraintSource() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcConstraint::setConstraintSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc4::IfcActorSelect* Ifc4x3_rc4::IfcConstraint::CreatingActor() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc4::IfcActorSelect>(true); }
 void Ifc4x3_rc4::IfcConstraint::setCreatingActor(::Ifc4x3_rc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcConstraint::CreationTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcConstraint::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcConstraint::UserDefinedGrade() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcConstraint::setUserDefinedGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc4::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc4::IfcConstraint::HasExternalReferences() const { return data_->getInverse(IFC4X3_RC4_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc4::IfcResourceConstraintRelationship::list::ptr Ifc4x3_rc4::IfcConstraint::PropertiesForConstraint() const { return data_->getInverse(IFC4X3_RC4_IfcResourceConstraintRelationship_type, 2)->as<IfcResourceConstraintRelationship>(); }
@@ -14867,7 +14867,7 @@ Ifc4x3_rc4::IfcConstraint::IfcConstraint(std::string v1_Name, boost::optional< s
 
 // Function implementations for IfcConstructionEquipmentResource
 boost::optional< ::Ifc4x3_rc4::IfcConstructionEquipmentResourceTypeEnum::Value > Ifc4x3_rc4::IfcConstructionEquipmentResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcConstructionEquipmentResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcConstructionEquipmentResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcConstructionEquipmentResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcConstructionEquipmentResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcConstructionEquipmentResource::declaration() const { return *IFC4X3_RC4_IfcConstructionEquipmentResource_type; }
@@ -14887,7 +14887,7 @@ Ifc4x3_rc4::IfcConstructionEquipmentResourceType::IfcConstructionEquipmentResour
 
 // Function implementations for IfcConstructionMaterialResource
 boost::optional< ::Ifc4x3_rc4::IfcConstructionMaterialResourceTypeEnum::Value > Ifc4x3_rc4::IfcConstructionMaterialResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcConstructionMaterialResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcConstructionMaterialResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcConstructionMaterialResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcConstructionMaterialResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcConstructionMaterialResource::declaration() const { return *IFC4X3_RC4_IfcConstructionMaterialResource_type; }
@@ -14907,7 +14907,7 @@ Ifc4x3_rc4::IfcConstructionMaterialResourceType::IfcConstructionMaterialResource
 
 // Function implementations for IfcConstructionProductResource
 boost::optional< ::Ifc4x3_rc4::IfcConstructionProductResourceTypeEnum::Value > Ifc4x3_rc4::IfcConstructionProductResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcConstructionProductResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcConstructionProductResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcConstructionProductResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcConstructionProductResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcConstructionProductResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcConstructionProductResource::declaration() const { return *IFC4X3_RC4_IfcConstructionProductResource_type; }
@@ -14929,7 +14929,7 @@ Ifc4x3_rc4::IfcConstructionProductResourceType::IfcConstructionProductResourceTy
 ::Ifc4x3_rc4::IfcResourceTime* Ifc4x3_rc4::IfcConstructionResource::Usage() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc4::IfcResourceTime>(true); }
 void Ifc4x3_rc4::IfcConstructionResource::setUsage(::Ifc4x3_rc4::IfcResourceTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAppliedValue >::ptr > Ifc4x3_rc4::IfcConstructionResource::BaseCosts() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc4::IfcAppliedValue >(); }
-void Ifc4x3_rc4::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcConstructionResource::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc4::IfcPhysicalQuantity* Ifc4x3_rc4::IfcConstructionResource::BaseQuantity() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc4::IfcPhysicalQuantity>(true); }
 void Ifc4x3_rc4::IfcConstructionResource::setBaseQuantity(::Ifc4x3_rc4::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -14941,7 +14941,7 @@ Ifc4x3_rc4::IfcConstructionResource::IfcConstructionResource(std::string v1_Glob
 
 // Function implementations for IfcConstructionResourceType
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAppliedValue >::ptr > Ifc4x3_rc4::IfcConstructionResourceType::BaseCosts() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc4::IfcAppliedValue >(); }
-void Ifc4x3_rc4::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcConstructionResourceType::setBaseCosts(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAppliedValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 ::Ifc4x3_rc4::IfcPhysicalQuantity* Ifc4x3_rc4::IfcConstructionResourceType::BaseQuantity() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc4::IfcPhysicalQuantity>(true); }
 void Ifc4x3_rc4::IfcConstructionResourceType::setBaseQuantity(::Ifc4x3_rc4::IfcPhysicalQuantity* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -14953,13 +14953,13 @@ Ifc4x3_rc4::IfcConstructionResourceType::IfcConstructionResourceType(std::string
 
 // Function implementations for IfcContext
 boost::optional< std::string > Ifc4x3_rc4::IfcContext::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcContext::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcContext::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcContext::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcContext::Phase() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcContext::setPhase(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcRepresentationContext >::ptr > Ifc4x3_rc4::IfcContext::RepresentationContexts() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc4::IfcRepresentationContext >(); }
-void Ifc4x3_rc4::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcContext::setRepresentationContexts(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcRepresentationContext >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcUnitAssignment* Ifc4x3_rc4::IfcContext::UnitsInContext() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc4::IfcUnitAssignment>(true); }
 void Ifc4x3_rc4::IfcContext::setUnitsInContext(::Ifc4x3_rc4::IfcUnitAssignment* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -14984,7 +14984,7 @@ Ifc4x3_rc4::IfcContextDependentUnit::IfcContextDependentUnit(::Ifc4x3_rc4::IfcDi
 
 // Function implementations for IfcControl
 boost::optional< std::string > Ifc4x3_rc4::IfcControl::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcControl::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc4::IfcRelAssignsToControl::list::ptr Ifc4x3_rc4::IfcControl::Controls() const { return data_->getInverse(IFC4X3_RC4_IfcRelAssignsToControl_type, 6)->as<IfcRelAssignsToControl>(); }
 
@@ -14995,7 +14995,7 @@ Ifc4x3_rc4::IfcControl::IfcControl(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwn
 
 // Function implementations for IfcController
 boost::optional< ::Ifc4x3_rc4::IfcControllerTypeEnum::Value > Ifc4x3_rc4::IfcController::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcControllerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcController::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcControllerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcController::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcControllerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcControllerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcController::declaration() const { return *IFC4X3_RC4_IfcController_type; }
@@ -15038,7 +15038,7 @@ Ifc4x3_rc4::IfcConversionBasedUnitWithOffset::IfcConversionBasedUnitWithOffset(:
 
 // Function implementations for IfcConveyorSegment
 boost::optional< ::Ifc4x3_rc4::IfcConveyorSegmentTypeEnum::Value > Ifc4x3_rc4::IfcConveyorSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcConveyorSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcConveyorSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcConveyorSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcConveyorSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcConveyorSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcConveyorSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcConveyorSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcConveyorSegment::declaration() const { return *IFC4X3_RC4_IfcConveyorSegment_type; }
@@ -15058,7 +15058,7 @@ Ifc4x3_rc4::IfcConveyorSegmentType::IfcConveyorSegmentType(std::string v1_Global
 
 // Function implementations for IfcCooledBeam
 boost::optional< ::Ifc4x3_rc4::IfcCooledBeamTypeEnum::Value > Ifc4x3_rc4::IfcCooledBeam::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCooledBeamTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCooledBeamTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCooledBeam::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCooledBeamTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCooledBeamTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCooledBeam::declaration() const { return *IFC4X3_RC4_IfcCooledBeam_type; }
@@ -15078,7 +15078,7 @@ Ifc4x3_rc4::IfcCooledBeamType::IfcCooledBeamType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcCoolingTower
 boost::optional< ::Ifc4x3_rc4::IfcCoolingTowerTypeEnum::Value > Ifc4x3_rc4::IfcCoolingTower::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCoolingTowerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCoolingTowerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCoolingTower::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCoolingTowerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCoolingTowerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCoolingTower::declaration() const { return *IFC4X3_RC4_IfcCoolingTower_type; }
@@ -15112,11 +15112,11 @@ Ifc4x3_rc4::IfcCoordinateOperation::IfcCoordinateOperation(::Ifc4x3_rc4::IfcCoor
 std::string Ifc4x3_rc4::IfcCoordinateReferenceSystem::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc4::IfcCoordinateReferenceSystem::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcCoordinateReferenceSystem::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcCoordinateReferenceSystem::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcCoordinateReferenceSystem::GeodeticDatum() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcCoordinateReferenceSystem::setGeodeticDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcCoordinateReferenceSystem::VerticalDatum() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcCoordinateReferenceSystem::setVerticalDatum(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 ::Ifc4x3_rc4::IfcCoordinateOperation::list::ptr Ifc4x3_rc4::IfcCoordinateReferenceSystem::HasCoordinateOperation() const { return data_->getInverse(IFC4X3_RC4_IfcCoordinateOperation_type, 0)->as<IfcCoordinateOperation>(); }
 
@@ -15129,7 +15129,7 @@ Ifc4x3_rc4::IfcCoordinateReferenceSystem::IfcCoordinateReferenceSystem(std::stri
 double Ifc4x3_rc4::IfcCosine::CosineTerm() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcCosine::setCosineTerm(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcCosine::ConstantTerm() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcCosine::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcCosine::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCosine::declaration() const { return *IFC4X3_RC4_IfcCosine_type; }
@@ -15139,11 +15139,11 @@ Ifc4x3_rc4::IfcCosine::IfcCosine(::Ifc4x3_rc4::IfcAxis2Placement* v1_Position, d
 
 // Function implementations for IfcCostItem
 boost::optional< ::Ifc4x3_rc4::IfcCostItemTypeEnum::Value > Ifc4x3_rc4::IfcCostItem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCostItemTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc4::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCostItemTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcCostItem::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCostItemTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCostItemTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcCostValue >::ptr > Ifc4x3_rc4::IfcCostItem::CostValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc4::IfcCostValue >(); }
-void Ifc4x3_rc4::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcCostItem::setCostValues(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcCostValue >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPhysicalQuantity >::ptr > Ifc4x3_rc4::IfcCostItem::CostQuantities() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc4::IfcPhysicalQuantity >(); }
-void Ifc4x3_rc4::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCostItem::setCostQuantities(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPhysicalQuantity >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCostItem::declaration() const { return *IFC4X3_RC4_IfcCostItem_type; }
@@ -15153,13 +15153,13 @@ Ifc4x3_rc4::IfcCostItem::IfcCostItem(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcCostSchedule
 boost::optional< ::Ifc4x3_rc4::IfcCostScheduleTypeEnum::Value > Ifc4x3_rc4::IfcCostSchedule::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCostScheduleTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc4::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCostScheduleTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcCostSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCostScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCostScheduleTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcCostSchedule::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcCostSchedule::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcCostSchedule::SubmittedOn() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCostSchedule::setSubmittedOn(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcCostSchedule::UpdateDate() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcCostSchedule::setUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCostSchedule::declaration() const { return *IFC4X3_RC4_IfcCostSchedule_type; }
@@ -15177,7 +15177,7 @@ Ifc4x3_rc4::IfcCostValue::IfcCostValue(boost::optional< std::string > v1_Name, b
 
 // Function implementations for IfcCourse
 boost::optional< ::Ifc4x3_rc4::IfcCourseTypeEnum::Value > Ifc4x3_rc4::IfcCourse::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCourseTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCourse::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCourseTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCourseTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCourse::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCourseTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCourseTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCourse::declaration() const { return *IFC4X3_RC4_IfcCourse_type; }
@@ -15197,7 +15197,7 @@ Ifc4x3_rc4::IfcCourseType::IfcCourseType(std::string v1_GlobalId, ::Ifc4x3_rc4::
 
 // Function implementations for IfcCovering
 boost::optional< ::Ifc4x3_rc4::IfcCoveringTypeEnum::Value > Ifc4x3_rc4::IfcCovering::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCoveringTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCoveringTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCovering::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCoveringTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCoveringTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc4::IfcRelCoversSpaces::list::ptr Ifc4x3_rc4::IfcCovering::CoversSpaces() const { return data_->getInverse(IFC4X3_RC4_IfcRelCoversSpaces_type, 5)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x3_rc4::IfcRelCoversBldgElements::list::ptr Ifc4x3_rc4::IfcCovering::CoversElements() const { return data_->getInverse(IFC4X3_RC4_IfcRelCoversBldgElements_type, 5)->as<IfcRelCoversBldgElements>(); }
@@ -15219,7 +15219,7 @@ Ifc4x3_rc4::IfcCoveringType::IfcCoveringType(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcCrewResource
 boost::optional< ::Ifc4x3_rc4::IfcCrewResourceTypeEnum::Value > Ifc4x3_rc4::IfcCrewResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCrewResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCrewResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcCrewResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCrewResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCrewResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCrewResource::declaration() const { return *IFC4X3_RC4_IfcCrewResource_type; }
@@ -15265,7 +15265,7 @@ void Ifc4x3_rc4::IfcCurrencyRelationship::setRelatedMonetaryUnit(::Ifc4x3_rc4::I
 double Ifc4x3_rc4::IfcCurrencyRelationship::ExchangeRate() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc4::IfcCurrencyRelationship::setExchangeRate(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcCurrencyRelationship::RateDateTime() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcCurrencyRelationship::setRateDateTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc4::IfcLibraryInformation* Ifc4x3_rc4::IfcCurrencyRelationship::RateSource() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcLibraryInformation>(true); }
 void Ifc4x3_rc4::IfcCurrencyRelationship::setRateSource(::Ifc4x3_rc4::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -15277,7 +15277,7 @@ Ifc4x3_rc4::IfcCurrencyRelationship::IfcCurrencyRelationship(boost::optional< st
 
 // Function implementations for IfcCurtainWall
 boost::optional< ::Ifc4x3_rc4::IfcCurtainWallTypeEnum::Value > Ifc4x3_rc4::IfcCurtainWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCurtainWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCurtainWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcCurtainWall::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcCurtainWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCurtainWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCurtainWall::declaration() const { return *IFC4X3_RC4_IfcCurtainWall_type; }
@@ -15355,7 +15355,7 @@ void Ifc4x3_rc4::IfcCurveStyle::setCurveWidth(::Ifc4x3_rc4::IfcSizeSelect* v) {
 ::Ifc4x3_rc4::IfcColour* Ifc4x3_rc4::IfcCurveStyle::CurveColour() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcColour>(true); }
 void Ifc4x3_rc4::IfcCurveStyle::setCurveColour(::Ifc4x3_rc4::IfcColour* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x3_rc4::IfcCurveStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcCurveStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcCurveStyle::declaration() const { return *IFC4X3_RC4_IfcCurveStyle_type; }
@@ -15365,7 +15365,7 @@ Ifc4x3_rc4::IfcCurveStyle::IfcCurveStyle(boost::optional< std::string > v1_Name,
 
 // Function implementations for IfcCurveStyleFont
 boost::optional< std::string > Ifc4x3_rc4::IfcCurveStyleFont::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcCurveStyleFont::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 aggregate_of< ::Ifc4x3_rc4::IfcCurveStyleFontPattern >::ptr Ifc4x3_rc4::IfcCurveStyleFont::PatternList() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc4::IfcCurveStyleFontPattern >(); }
 void Ifc4x3_rc4::IfcCurveStyleFont::setPatternList(aggregate_of< ::Ifc4x3_rc4::IfcCurveStyleFontPattern >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 
@@ -15377,7 +15377,7 @@ Ifc4x3_rc4::IfcCurveStyleFont::IfcCurveStyleFont(boost::optional< std::string >
 
 // Function implementations for IfcCurveStyleFontAndScaling
 boost::optional< std::string > Ifc4x3_rc4::IfcCurveStyleFontAndScaling::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcCurveStyleFontAndScaling::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc4::IfcCurveStyleFontSelect* Ifc4x3_rc4::IfcCurveStyleFontAndScaling::CurveFont() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc4::IfcCurveStyleFontSelect>(true); }
 void Ifc4x3_rc4::IfcCurveStyleFontAndScaling::setCurveFont(::Ifc4x3_rc4::IfcCurveStyleFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 double Ifc4x3_rc4::IfcCurveStyleFontAndScaling::CurveFontScaling() const {  double v = *data_->getArgument(2); return v; }
@@ -15413,7 +15413,7 @@ Ifc4x3_rc4::IfcCylindricalSurface::IfcCylindricalSurface(::Ifc4x3_rc4::IfcAxis2P
 
 // Function implementations for IfcDamper
 boost::optional< ::Ifc4x3_rc4::IfcDamperTypeEnum::Value > Ifc4x3_rc4::IfcDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDamper::declaration() const { return *IFC4X3_RC4_IfcDamper_type; }
@@ -15453,7 +15453,7 @@ void Ifc4x3_rc4::IfcDerivedProfileDef::setParentProfile(::Ifc4x3_rc4::IfcProfile
 ::Ifc4x3_rc4::IfcCartesianTransformationOperator2D* Ifc4x3_rc4::IfcDerivedProfileDef::Operator() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x3_rc4::IfcDerivedProfileDef::setOperator(::Ifc4x3_rc4::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDerivedProfileDef::Label() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcDerivedProfileDef::setLabel(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDerivedProfileDef::declaration() const { return *IFC4X3_RC4_IfcDerivedProfileDef_type; }
@@ -15467,7 +15467,7 @@ void Ifc4x3_rc4::IfcDerivedUnit::setElements(aggregate_of< ::Ifc4x3_rc4::IfcDeri
 ::Ifc4x3_rc4::IfcDerivedUnitEnum::Value Ifc4x3_rc4::IfcDerivedUnit::UnitType() const {  return ::Ifc4x3_rc4::IfcDerivedUnitEnum::FromString(*data_->getArgument(1)); }
 void Ifc4x3_rc4::IfcDerivedUnit::setUnitType(::Ifc4x3_rc4::IfcDerivedUnitEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcDerivedUnitEnum::ToString(v)));data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDerivedUnit::UserDefinedType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcDerivedUnit::setUserDefinedType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDerivedUnit::declaration() const { return *IFC4X3_RC4_IfcDerivedUnit_type; }
@@ -15543,7 +15543,7 @@ Ifc4x3_rc4::IfcDirectrixDerivedReferenceSweptAreaSolid::IfcDirectrixDerivedRefer
 
 // Function implementations for IfcDiscreteAccessory
 boost::optional< ::Ifc4x3_rc4::IfcDiscreteAccessoryTypeEnum::Value > Ifc4x3_rc4::IfcDiscreteAccessory::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDiscreteAccessoryTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDiscreteAccessoryTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcDiscreteAccessory::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDiscreteAccessoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDiscreteAccessoryTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDiscreteAccessory::declaration() const { return *IFC4X3_RC4_IfcDiscreteAccessory_type; }
@@ -15563,7 +15563,7 @@ Ifc4x3_rc4::IfcDiscreteAccessoryType::IfcDiscreteAccessoryType(std::string v1_Gl
 
 // Function implementations for IfcDistributionBoard
 boost::optional< ::Ifc4x3_rc4::IfcDistributionBoardTypeEnum::Value > Ifc4x3_rc4::IfcDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDistributionBoard::declaration() const { return *IFC4X3_RC4_IfcDistributionBoard_type; }
@@ -15583,7 +15583,7 @@ Ifc4x3_rc4::IfcDistributionBoardType::IfcDistributionBoardType(std::string v1_Gl
 
 // Function implementations for IfcDistributionChamberElement
 boost::optional< ::Ifc4x3_rc4::IfcDistributionChamberElementTypeEnum::Value > Ifc4x3_rc4::IfcDistributionChamberElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDistributionChamberElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDistributionChamberElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcDistributionChamberElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDistributionChamberElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDistributionChamberElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDistributionChamberElement::declaration() const { return *IFC4X3_RC4_IfcDistributionChamberElement_type; }
@@ -15662,11 +15662,11 @@ Ifc4x3_rc4::IfcDistributionFlowElementType::IfcDistributionFlowElementType(std::
 
 // Function implementations for IfcDistributionPort
 boost::optional< ::Ifc4x3_rc4::IfcFlowDirectionEnum::Value > Ifc4x3_rc4::IfcDistributionPort::FlowDirection() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcFlowDirectionEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc4::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x3_rc4::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFlowDirectionEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcDistributionPort::setFlowDirection(boost::optional< ::Ifc4x3_rc4::IfcFlowDirectionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFlowDirectionEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcDistributionPortTypeEnum::Value > Ifc4x3_rc4::IfcDistributionPort::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDistributionPortTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDistributionPortTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcDistributionPort::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDistributionPortTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDistributionPortTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcDistributionSystemEnum::Value > Ifc4x3_rc4::IfcDistributionPort::SystemType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDistributionSystemEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x3_rc4::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcDistributionPort::setSystemType(boost::optional< ::Ifc4x3_rc4::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDistributionPort::declaration() const { return *IFC4X3_RC4_IfcDistributionPort_type; }
@@ -15676,9 +15676,9 @@ Ifc4x3_rc4::IfcDistributionPort::IfcDistributionPort(std::string v1_GlobalId, ::
 
 // Function implementations for IfcDistributionSystem
 boost::optional< std::string > Ifc4x3_rc4::IfcDistributionSystem::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcDistributionSystem::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcDistributionSystemEnum::Value > Ifc4x3_rc4::IfcDistributionSystem::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDistributionSystemEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc4::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDistributionSystemEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcDistributionSystem::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDistributionSystemEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDistributionSystemEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDistributionSystem::declaration() const { return *IFC4X3_RC4_IfcDistributionSystem_type; }
@@ -15692,35 +15692,35 @@ void Ifc4x3_rc4::IfcDocumentInformation::setIdentification(std::string v) { {Ifc
 std::string Ifc4x3_rc4::IfcDocumentInformation::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcDocumentInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::Location() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::Purpose() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::IntendedUse() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setIntendedUse(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::Scope() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setScope(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::Revision() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setRevision(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcActorSelect* Ifc4x3_rc4::IfcDocumentInformation::DocumentOwner() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc4::IfcActorSelect>(true); }
 void Ifc4x3_rc4::IfcDocumentInformation::setDocumentOwner(::Ifc4x3_rc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc4::IfcDocumentInformation::Editors() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setEditors(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::CreationTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setCreationTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::LastRevisionTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setLastRevisionTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::ElectronicFormat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setElectronicFormat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::ValidFrom() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setValidFrom(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformation::ValidUntil() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc4::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setValidUntil(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcDocumentConfidentialityEnum::Value > Ifc4x3_rc4::IfcDocumentInformation::Confidentiality() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDocumentConfidentialityEnum::FromString(*data_->getArgument(15)); }
-void Ifc4x3_rc4::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x3_rc4::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDocumentConfidentialityEnum::ToString(*v)));data_->setArgument(15,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setConfidentiality(boost::optional< ::Ifc4x3_rc4::IfcDocumentConfidentialityEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDocumentConfidentialityEnum::ToString(*v)));}data_->setArgument(15,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcDocumentStatusEnum::Value > Ifc4x3_rc4::IfcDocumentInformation::Status() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDocumentStatusEnum::FromString(*data_->getArgument(16)); }
-void Ifc4x3_rc4::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x3_rc4::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDocumentStatusEnum::ToString(*v)));data_->setArgument(16,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformation::setStatus(boost::optional< ::Ifc4x3_rc4::IfcDocumentStatusEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDocumentStatusEnum::ToString(*v)));}data_->setArgument(16,attr);} }
 
 ::Ifc4x3_rc4::IfcRelAssociatesDocument::list::ptr Ifc4x3_rc4::IfcDocumentInformation::DocumentInfoForObjects() const { return data_->getInverse(IFC4X3_RC4_IfcRelAssociatesDocument_type, 5)->as<IfcRelAssociatesDocument>(); }
 ::Ifc4x3_rc4::IfcDocumentReference::list::ptr Ifc4x3_rc4::IfcDocumentInformation::HasDocumentReferences() const { return data_->getInverse(IFC4X3_RC4_IfcDocumentReference_type, 4)->as<IfcDocumentReference>(); }
@@ -15738,7 +15738,7 @@ void Ifc4x3_rc4::IfcDocumentInformationRelationship::setRelatingDocument(::Ifc4x
 aggregate_of< ::Ifc4x3_rc4::IfcDocumentInformation >::ptr Ifc4x3_rc4::IfcDocumentInformationRelationship::RelatedDocuments() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc4::IfcDocumentInformation >(); }
 void Ifc4x3_rc4::IfcDocumentInformationRelationship::setRelatedDocuments(aggregate_of< ::Ifc4x3_rc4::IfcDocumentInformation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentInformationRelationship::RelationshipType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcDocumentInformationRelationship::setRelationshipType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDocumentInformationRelationship::declaration() const { return *IFC4X3_RC4_IfcDocumentInformationRelationship_type; }
@@ -15748,7 +15748,7 @@ Ifc4x3_rc4::IfcDocumentInformationRelationship::IfcDocumentInformationRelationsh
 
 // Function implementations for IfcDocumentReference
 boost::optional< std::string > Ifc4x3_rc4::IfcDocumentReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcDocumentReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc4::IfcDocumentInformation* Ifc4x3_rc4::IfcDocumentReference::ReferencedDocument() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc4::IfcDocumentInformation>(true); }
 void Ifc4x3_rc4::IfcDocumentReference::setReferencedDocument(::Ifc4x3_rc4::IfcDocumentInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -15761,15 +15761,15 @@ Ifc4x3_rc4::IfcDocumentReference::IfcDocumentReference(boost::optional< std::str
 
 // Function implementations for IfcDoor
 boost::optional< double > Ifc4x3_rc4::IfcDoor::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcDoor::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoor::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcDoor::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcDoorTypeEnum::Value > Ifc4x3_rc4::IfcDoor::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDoorTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDoorTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcDoor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDoorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDoorTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcDoorTypeOperationEnum::Value > Ifc4x3_rc4::IfcDoor::OperationType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc4::IfcDoor::setOperationType(boost::optional< ::Ifc4x3_rc4::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDoorTypeOperationEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcDoor::setOperationType(boost::optional< ::Ifc4x3_rc4::IfcDoorTypeOperationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDoorTypeOperationEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDoor::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcDoor::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDoor::declaration() const { return *IFC4X3_RC4_IfcDoor_type; }
@@ -15779,31 +15779,31 @@ Ifc4x3_rc4::IfcDoor::IfcDoor(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHist
 
 // Function implementations for IfcDoorLiningProperties
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::ThresholdDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setThresholdDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::ThresholdThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setThresholdThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::TransomThickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::TransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::LiningOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::ThresholdOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setThresholdOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::CasingThickness() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setCasingThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::CasingDepth() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setCasingDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 ::Ifc4x3_rc4::IfcShapeAspect* Ifc4x3_rc4::IfcDoorLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(14)))->as<::Ifc4x3_rc4::IfcShapeAspect>(true); }
 void Ifc4x3_rc4::IfcDoorLiningProperties::setShapeAspectStyle(::Ifc4x3_rc4::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc4::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc4::IfcDoorLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDoorLiningProperties::declaration() const { return *IFC4X3_RC4_IfcDoorLiningProperties_type; }
@@ -15813,11 +15813,11 @@ Ifc4x3_rc4::IfcDoorLiningProperties::IfcDoorLiningProperties(std::string v1_Glob
 
 // Function implementations for IfcDoorPanelProperties
 boost::optional< double > Ifc4x3_rc4::IfcDoorPanelProperties::PanelDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcDoorPanelProperties::setPanelDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc4::IfcDoorPanelOperationEnum::Value Ifc4x3_rc4::IfcDoorPanelProperties::PanelOperation() const {  return ::Ifc4x3_rc4::IfcDoorPanelOperationEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc4::IfcDoorPanelProperties::setPanelOperation(::Ifc4x3_rc4::IfcDoorPanelOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcDoorPanelOperationEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcDoorPanelProperties::PanelWidth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcDoorPanelProperties::setPanelWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc4::IfcDoorPanelPositionEnum::Value Ifc4x3_rc4::IfcDoorPanelProperties::PanelPosition() const {  return ::Ifc4x3_rc4::IfcDoorPanelPositionEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc4::IfcDoorPanelProperties::setPanelPosition(::Ifc4x3_rc4::IfcDoorPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcDoorPanelPositionEnum::ToString(v)));data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcShapeAspect* Ifc4x3_rc4::IfcDoorPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc4::IfcShapeAspect>(true); }
@@ -15859,9 +15859,9 @@ void Ifc4x3_rc4::IfcDoorType::setPredefinedType(::Ifc4x3_rc4::IfcDoorTypeEnum::V
 ::Ifc4x3_rc4::IfcDoorTypeOperationEnum::Value Ifc4x3_rc4::IfcDoorType::OperationType() const {  return ::Ifc4x3_rc4::IfcDoorTypeOperationEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc4::IfcDoorType::setOperationType(::Ifc4x3_rc4::IfcDoorTypeOperationEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcDoorTypeOperationEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x3_rc4::IfcDoorType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcDoorType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcDoorType::UserDefinedOperationType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcDoorType::setUserDefinedOperationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDoorType::declaration() const { return *IFC4X3_RC4_IfcDoorType_type; }
@@ -15887,7 +15887,7 @@ Ifc4x3_rc4::IfcDraughtingPreDefinedCurveFont::IfcDraughtingPreDefinedCurveFont(s
 
 // Function implementations for IfcDuctFitting
 boost::optional< ::Ifc4x3_rc4::IfcDuctFittingTypeEnum::Value > Ifc4x3_rc4::IfcDuctFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDuctFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDuctFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcDuctFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDuctFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDuctFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDuctFitting::declaration() const { return *IFC4X3_RC4_IfcDuctFitting_type; }
@@ -15907,7 +15907,7 @@ Ifc4x3_rc4::IfcDuctFittingType::IfcDuctFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcDuctSegment
 boost::optional< ::Ifc4x3_rc4::IfcDuctSegmentTypeEnum::Value > Ifc4x3_rc4::IfcDuctSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDuctSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDuctSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcDuctSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDuctSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDuctSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDuctSegment::declaration() const { return *IFC4X3_RC4_IfcDuctSegment_type; }
@@ -15927,7 +15927,7 @@ Ifc4x3_rc4::IfcDuctSegmentType::IfcDuctSegmentType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcDuctSilencer
 boost::optional< ::Ifc4x3_rc4::IfcDuctSilencerTypeEnum::Value > Ifc4x3_rc4::IfcDuctSilencer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDuctSilencerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDuctSilencerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcDuctSilencer::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcDuctSilencerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDuctSilencerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcDuctSilencer::declaration() const { return *IFC4X3_RC4_IfcDuctSilencer_type; }
@@ -15947,7 +15947,7 @@ Ifc4x3_rc4::IfcDuctSilencerType::IfcDuctSilencerType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcEarthworksCut
 boost::optional< ::Ifc4x3_rc4::IfcEarthworksCutTypeEnum::Value > Ifc4x3_rc4::IfcEarthworksCut::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcEarthworksCutTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcEarthworksCut::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEarthworksCutTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEarthworksCutTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcEarthworksCut::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEarthworksCutTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEarthworksCutTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcEarthworksCut::declaration() const { return *IFC4X3_RC4_IfcEarthworksCut_type; }
@@ -15965,7 +15965,7 @@ Ifc4x3_rc4::IfcEarthworksElement::IfcEarthworksElement(std::string v1_GlobalId,
 
 // Function implementations for IfcEarthworksFill
 boost::optional< ::Ifc4x3_rc4::IfcEarthworksFillTypeEnum::Value > Ifc4x3_rc4::IfcEarthworksFill::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcEarthworksFillTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcEarthworksFill::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEarthworksFillTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEarthworksFillTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcEarthworksFill::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEarthworksFillTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEarthworksFillTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcEarthworksFill::declaration() const { return *IFC4X3_RC4_IfcEarthworksFill_type; }
@@ -16009,7 +16009,7 @@ Ifc4x3_rc4::IfcEdgeLoop::IfcEdgeLoop(aggregate_of< ::Ifc4x3_rc4::IfcOrientedEdge
 
 // Function implementations for IfcElectricAppliance
 boost::optional< ::Ifc4x3_rc4::IfcElectricApplianceTypeEnum::Value > Ifc4x3_rc4::IfcElectricAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcElectricApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcElectricAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcElectricAppliance::declaration() const { return *IFC4X3_RC4_IfcElectricAppliance_type; }
@@ -16029,7 +16029,7 @@ Ifc4x3_rc4::IfcElectricApplianceType::IfcElectricApplianceType(std::string v1_Gl
 
 // Function implementations for IfcElectricDistributionBoard
 boost::optional< ::Ifc4x3_rc4::IfcElectricDistributionBoardTypeEnum::Value > Ifc4x3_rc4::IfcElectricDistributionBoard::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcElectricDistributionBoardTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricDistributionBoardTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcElectricDistributionBoard::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricDistributionBoardTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricDistributionBoardTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcElectricDistributionBoard::declaration() const { return *IFC4X3_RC4_IfcElectricDistributionBoard_type; }
@@ -16049,7 +16049,7 @@ Ifc4x3_rc4::IfcElectricDistributionBoardType::IfcElectricDistributionBoardType(s
 
 // Function implementations for IfcElectricFlowStorageDevice
 boost::optional< ::Ifc4x3_rc4::IfcElectricFlowStorageDeviceTypeEnum::Value > Ifc4x3_rc4::IfcElectricFlowStorageDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcElectricFlowStorageDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcElectricFlowStorageDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricFlowStorageDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricFlowStorageDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcElectricFlowStorageDevice::declaration() const { return *IFC4X3_RC4_IfcElectricFlowStorageDevice_type; }
@@ -16069,7 +16069,7 @@ Ifc4x3_rc4::IfcElectricFlowStorageDeviceType::IfcElectricFlowStorageDeviceType(s
 
 // Function implementations for IfcElectricFlowTreatmentDevice
 boost::optional< ::Ifc4x3_rc4::IfcElectricFlowTreatmentDeviceTypeEnum::Value > Ifc4x3_rc4::IfcElectricFlowTreatmentDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcElectricFlowTreatmentDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcElectricFlowTreatmentDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricFlowTreatmentDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricFlowTreatmentDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcElectricFlowTreatmentDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricFlowTreatmentDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricFlowTreatmentDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcElectricFlowTreatmentDevice::declaration() const { return *IFC4X3_RC4_IfcElectricFlowTreatmentDevice_type; }
@@ -16089,7 +16089,7 @@ Ifc4x3_rc4::IfcElectricFlowTreatmentDeviceType::IfcElectricFlowTreatmentDeviceTy
 
 // Function implementations for IfcElectricGenerator
 boost::optional< ::Ifc4x3_rc4::IfcElectricGeneratorTypeEnum::Value > Ifc4x3_rc4::IfcElectricGenerator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcElectricGeneratorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricGeneratorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcElectricGenerator::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricGeneratorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricGeneratorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcElectricGenerator::declaration() const { return *IFC4X3_RC4_IfcElectricGenerator_type; }
@@ -16109,7 +16109,7 @@ Ifc4x3_rc4::IfcElectricGeneratorType::IfcElectricGeneratorType(std::string v1_Gl
 
 // Function implementations for IfcElectricMotor
 boost::optional< ::Ifc4x3_rc4::IfcElectricMotorTypeEnum::Value > Ifc4x3_rc4::IfcElectricMotor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcElectricMotorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricMotorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcElectricMotor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricMotorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricMotorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcElectricMotor::declaration() const { return *IFC4X3_RC4_IfcElectricMotor_type; }
@@ -16129,7 +16129,7 @@ Ifc4x3_rc4::IfcElectricMotorType::IfcElectricMotorType(std::string v1_GlobalId,
 
 // Function implementations for IfcElectricTimeControl
 boost::optional< ::Ifc4x3_rc4::IfcElectricTimeControlTypeEnum::Value > Ifc4x3_rc4::IfcElectricTimeControl::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcElectricTimeControlTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricTimeControlTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcElectricTimeControl::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElectricTimeControlTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElectricTimeControlTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcElectricTimeControl::declaration() const { return *IFC4X3_RC4_IfcElectricTimeControl_type; }
@@ -16149,7 +16149,7 @@ Ifc4x3_rc4::IfcElectricTimeControlType::IfcElectricTimeControlType(std::string v
 
 // Function implementations for IfcElement
 boost::optional< std::string > Ifc4x3_rc4::IfcElement::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcElement::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc4::IfcRelFillsElement::list::ptr Ifc4x3_rc4::IfcElement::FillsVoids() const { return data_->getInverse(IFC4X3_RC4_IfcRelFillsElement_type, 5)->as<IfcRelFillsElement>(); }
 ::Ifc4x3_rc4::IfcRelConnectsElements::list::ptr Ifc4x3_rc4::IfcElement::ConnectedTo() const { return data_->getInverse(IFC4X3_RC4_IfcRelConnectsElements_type, 5)->as<IfcRelConnectsElements>(); }
@@ -16171,9 +16171,9 @@ Ifc4x3_rc4::IfcElement::IfcElement(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwn
 
 // Function implementations for IfcElementAssembly
 boost::optional< ::Ifc4x3_rc4::IfcAssemblyPlaceEnum::Value > Ifc4x3_rc4::IfcElementAssembly::AssemblyPlace() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x3_rc4::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAssemblyPlaceEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcElementAssembly::setAssemblyPlace(boost::optional< ::Ifc4x3_rc4::IfcAssemblyPlaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcAssemblyPlaceEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcElementAssemblyTypeEnum::Value > Ifc4x3_rc4::IfcElementAssembly::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcElementAssemblyTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElementAssemblyTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcElementAssembly::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcElementAssemblyTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElementAssemblyTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcElementAssembly::declaration() const { return *IFC4X3_RC4_IfcElementAssembly_type; }
@@ -16209,7 +16209,7 @@ Ifc4x3_rc4::IfcElementComponentType::IfcElementComponentType(std::string v1_Glob
 
 // Function implementations for IfcElementQuantity
 boost::optional< std::string > Ifc4x3_rc4::IfcElementQuantity::MethodOfMeasurement() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcElementQuantity::setMethodOfMeasurement(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x3_rc4::IfcPhysicalQuantity >::ptr Ifc4x3_rc4::IfcElementQuantity::Quantities() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc4::IfcPhysicalQuantity >(); }
 void Ifc4x3_rc4::IfcElementQuantity::setQuantities(aggregate_of< ::Ifc4x3_rc4::IfcPhysicalQuantity >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -16221,7 +16221,7 @@ Ifc4x3_rc4::IfcElementQuantity::IfcElementQuantity(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcElementType
 boost::optional< std::string > Ifc4x3_rc4::IfcElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcElementType::declaration() const { return *IFC4X3_RC4_IfcElementType_type; }
@@ -16281,7 +16281,7 @@ Ifc4x3_rc4::IfcEnergyConversionDeviceType::IfcEnergyConversionDeviceType(std::st
 
 // Function implementations for IfcEngine
 boost::optional< ::Ifc4x3_rc4::IfcEngineTypeEnum::Value > Ifc4x3_rc4::IfcEngine::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcEngineTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEngineTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcEngine::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEngineTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEngineTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcEngine::declaration() const { return *IFC4X3_RC4_IfcEngine_type; }
@@ -16301,7 +16301,7 @@ Ifc4x3_rc4::IfcEngineType::IfcEngineType(std::string v1_GlobalId, ::Ifc4x3_rc4::
 
 // Function implementations for IfcEvaporativeCooler
 boost::optional< ::Ifc4x3_rc4::IfcEvaporativeCoolerTypeEnum::Value > Ifc4x3_rc4::IfcEvaporativeCooler::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcEvaporativeCoolerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEvaporativeCoolerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcEvaporativeCooler::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEvaporativeCoolerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEvaporativeCoolerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcEvaporativeCooler::declaration() const { return *IFC4X3_RC4_IfcEvaporativeCooler_type; }
@@ -16321,7 +16321,7 @@ Ifc4x3_rc4::IfcEvaporativeCoolerType::IfcEvaporativeCoolerType(std::string v1_Gl
 
 // Function implementations for IfcEvaporator
 boost::optional< ::Ifc4x3_rc4::IfcEvaporatorTypeEnum::Value > Ifc4x3_rc4::IfcEvaporator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcEvaporatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEvaporatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcEvaporator::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEvaporatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEvaporatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcEvaporator::declaration() const { return *IFC4X3_RC4_IfcEvaporator_type; }
@@ -16341,11 +16341,11 @@ Ifc4x3_rc4::IfcEvaporatorType::IfcEvaporatorType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcEvent
 boost::optional< ::Ifc4x3_rc4::IfcEventTypeEnum::Value > Ifc4x3_rc4::IfcEvent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcEventTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc4::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEventTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcEvent::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcEventTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEventTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcEventTriggerTypeEnum::Value > Ifc4x3_rc4::IfcEvent::EventTriggerType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x3_rc4::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEventTriggerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcEvent::setEventTriggerType(boost::optional< ::Ifc4x3_rc4::IfcEventTriggerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcEventTriggerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcEvent::UserDefinedEventTriggerType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcEvent::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 ::Ifc4x3_rc4::IfcEventTime* Ifc4x3_rc4::IfcEvent::EventOccurenceTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc4::IfcEventTime>(true); }
 void Ifc4x3_rc4::IfcEvent::setEventOccurenceTime(::Ifc4x3_rc4::IfcEventTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(10,attr);} }
 
@@ -16357,13 +16357,13 @@ Ifc4x3_rc4::IfcEvent::IfcEvent(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHi
 
 // Function implementations for IfcEventTime
 boost::optional< std::string > Ifc4x3_rc4::IfcEventTime::ActualDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcEventTime::setActualDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcEventTime::EarlyDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcEventTime::setEarlyDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcEventTime::LateDate() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcEventTime::setLateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcEventTime::ScheduleDate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcEventTime::setScheduleDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcEventTime::declaration() const { return *IFC4X3_RC4_IfcEventTime_type; }
@@ -16377,7 +16377,7 @@ void Ifc4x3_rc4::IfcEventType::setPredefinedType(::Ifc4x3_rc4::IfcEventTypeEnum:
 ::Ifc4x3_rc4::IfcEventTriggerTypeEnum::Value Ifc4x3_rc4::IfcEventType::EventTriggerType() const {  return ::Ifc4x3_rc4::IfcEventTriggerTypeEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc4::IfcEventType::setEventTriggerType(::Ifc4x3_rc4::IfcEventTriggerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcEventTriggerTypeEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcEventType::UserDefinedEventTriggerType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcEventType::setUserDefinedEventTriggerType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcEventType::declaration() const { return *IFC4X3_RC4_IfcEventType_type; }
@@ -16387,9 +16387,9 @@ Ifc4x3_rc4::IfcEventType::IfcEventType(std::string v1_GlobalId, ::Ifc4x3_rc4::If
 
 // Function implementations for IfcExtendedProperties
 boost::optional< std::string > Ifc4x3_rc4::IfcExtendedProperties::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcExtendedProperties::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcExtendedProperties::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcExtendedProperties::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc4::IfcProperty >::ptr Ifc4x3_rc4::IfcExtendedProperties::Properties() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc4::IfcProperty >(); }
 void Ifc4x3_rc4::IfcExtendedProperties::setProperties(aggregate_of< ::Ifc4x3_rc4::IfcProperty >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -16409,11 +16409,11 @@ Ifc4x3_rc4::IfcExternalInformation::IfcExternalInformation() : IfcUtil::IfcBaseE
 
 // Function implementations for IfcExternalReference
 boost::optional< std::string > Ifc4x3_rc4::IfcExternalReference::Location() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcExternalReference::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcExternalReference::Identification() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcExternalReference::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcExternalReference::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcExternalReference::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc4::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc4::IfcExternalReference::ExternalReferenceForResources() const { return data_->getInverse(IFC4X3_RC4_IfcExternalReferenceRelationship_type, 2)->as<IfcExternalReferenceRelationship>(); }
 
@@ -16436,7 +16436,7 @@ Ifc4x3_rc4::IfcExternalReferenceRelationship::IfcExternalReferenceRelationship(b
 
 // Function implementations for IfcExternalSpatialElement
 boost::optional< ::Ifc4x3_rc4::IfcExternalSpatialElementTypeEnum::Value > Ifc4x3_rc4::IfcExternalSpatialElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcExternalSpatialElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcExternalSpatialElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcExternalSpatialElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcExternalSpatialElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcExternalSpatialElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc4::IfcRelSpaceBoundary::list::ptr Ifc4x3_rc4::IfcExternalSpatialElement::BoundedBy() const { return data_->getInverse(IFC4X3_RC4_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
 
@@ -16592,17 +16592,17 @@ Ifc4x3_rc4::IfcFacilityPart::IfcFacilityPart(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcFailureConnectionCondition
 boost::optional< double > Ifc4x3_rc4::IfcFailureConnectionCondition::TensionFailureX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcFailureConnectionCondition::setTensionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcFailureConnectionCondition::TensionFailureY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcFailureConnectionCondition::setTensionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcFailureConnectionCondition::TensionFailureZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcFailureConnectionCondition::setTensionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcFailureConnectionCondition::CompressionFailureX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcFailureConnectionCondition::setCompressionFailureX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcFailureConnectionCondition::CompressionFailureY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcFailureConnectionCondition::setCompressionFailureY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcFailureConnectionCondition::CompressionFailureZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcFailureConnectionCondition::setCompressionFailureZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFailureConnectionCondition::declaration() const { return *IFC4X3_RC4_IfcFailureConnectionCondition_type; }
@@ -16612,7 +16612,7 @@ Ifc4x3_rc4::IfcFailureConnectionCondition::IfcFailureConnectionCondition(boost::
 
 // Function implementations for IfcFan
 boost::optional< ::Ifc4x3_rc4::IfcFanTypeEnum::Value > Ifc4x3_rc4::IfcFan::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcFanTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcFan::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFanTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcFan::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFanTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFan::declaration() const { return *IFC4X3_RC4_IfcFan_type; }
@@ -16632,7 +16632,7 @@ Ifc4x3_rc4::IfcFanType::IfcFanType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwn
 
 // Function implementations for IfcFastener
 boost::optional< ::Ifc4x3_rc4::IfcFastenerTypeEnum::Value > Ifc4x3_rc4::IfcFastener::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcFastenerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFastenerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFastenerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFastener::declaration() const { return *IFC4X3_RC4_IfcFastener_type; }
@@ -16680,7 +16680,7 @@ Ifc4x3_rc4::IfcFeatureElementSubtraction::IfcFeatureElementSubtraction(std::stri
 aggregate_of_instance::ptr Ifc4x3_rc4::IfcFillAreaStyle::FillStyles() const {  aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcFillAreaStyle::setFillStyles(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc4::IfcFillAreaStyle::ModelOrDraughting() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcFillAreaStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcFillAreaStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFillAreaStyle::declaration() const { return *IFC4X3_RC4_IfcFillAreaStyle_type; }
@@ -16722,7 +16722,7 @@ Ifc4x3_rc4::IfcFillAreaStyleTiles::IfcFillAreaStyleTiles(aggregate_of< ::Ifc4x3_
 
 // Function implementations for IfcFilter
 boost::optional< ::Ifc4x3_rc4::IfcFilterTypeEnum::Value > Ifc4x3_rc4::IfcFilter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcFilterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFilterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcFilter::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFilterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFilterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFilter::declaration() const { return *IFC4X3_RC4_IfcFilter_type; }
@@ -16742,7 +16742,7 @@ Ifc4x3_rc4::IfcFilterType::IfcFilterType(std::string v1_GlobalId, ::Ifc4x3_rc4::
 
 // Function implementations for IfcFireSuppressionTerminal
 boost::optional< ::Ifc4x3_rc4::IfcFireSuppressionTerminalTypeEnum::Value > Ifc4x3_rc4::IfcFireSuppressionTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcFireSuppressionTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcFireSuppressionTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFireSuppressionTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFireSuppressionTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFireSuppressionTerminal::declaration() const { return *IFC4X3_RC4_IfcFireSuppressionTerminal_type; }
@@ -16804,7 +16804,7 @@ Ifc4x3_rc4::IfcFlowFittingType::IfcFlowFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcFlowInstrument
 boost::optional< ::Ifc4x3_rc4::IfcFlowInstrumentTypeEnum::Value > Ifc4x3_rc4::IfcFlowInstrument::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcFlowInstrumentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFlowInstrumentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcFlowInstrument::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFlowInstrumentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFlowInstrumentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFlowInstrument::declaration() const { return *IFC4X3_RC4_IfcFlowInstrument_type; }
@@ -16824,7 +16824,7 @@ Ifc4x3_rc4::IfcFlowInstrumentType::IfcFlowInstrumentType(std::string v1_GlobalId
 
 // Function implementations for IfcFlowMeter
 boost::optional< ::Ifc4x3_rc4::IfcFlowMeterTypeEnum::Value > Ifc4x3_rc4::IfcFlowMeter::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcFlowMeterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFlowMeterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcFlowMeter::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFlowMeterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFlowMeterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFlowMeter::declaration() const { return *IFC4X3_RC4_IfcFlowMeter_type; }
@@ -16924,7 +16924,7 @@ Ifc4x3_rc4::IfcFlowTreatmentDeviceType::IfcFlowTreatmentDeviceType(std::string v
 
 // Function implementations for IfcFooting
 boost::optional< ::Ifc4x3_rc4::IfcFootingTypeEnum::Value > Ifc4x3_rc4::IfcFooting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcFootingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFootingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcFooting::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFootingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFootingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFooting::declaration() const { return *IFC4X3_RC4_IfcFooting_type; }
@@ -16960,7 +16960,7 @@ Ifc4x3_rc4::IfcFurnishingElementType::IfcFurnishingElementType(std::string v1_Gl
 
 // Function implementations for IfcFurniture
 boost::optional< ::Ifc4x3_rc4::IfcFurnitureTypeEnum::Value > Ifc4x3_rc4::IfcFurniture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcFurnitureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcFurniture::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFurniture::declaration() const { return *IFC4X3_RC4_IfcFurniture_type; }
@@ -16972,7 +16972,7 @@ Ifc4x3_rc4::IfcFurniture::IfcFurniture(std::string v1_GlobalId, ::Ifc4x3_rc4::If
 ::Ifc4x3_rc4::IfcAssemblyPlaceEnum::Value Ifc4x3_rc4::IfcFurnitureType::AssemblyPlace() const {  return ::Ifc4x3_rc4::IfcAssemblyPlaceEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc4::IfcFurnitureType::setAssemblyPlace(::Ifc4x3_rc4::IfcAssemblyPlaceEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcAssemblyPlaceEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcFurnitureTypeEnum::Value > Ifc4x3_rc4::IfcFurnitureType::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcFurnitureTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFurnitureTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcFurnitureType::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcFurnitureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcFurnitureTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcFurnitureType::declaration() const { return *IFC4X3_RC4_IfcFurnitureType_type; }
@@ -16982,7 +16982,7 @@ Ifc4x3_rc4::IfcFurnitureType::IfcFurnitureType(std::string v1_GlobalId, ::Ifc4x3
 
 // Function implementations for IfcGeographicElement
 boost::optional< ::Ifc4x3_rc4::IfcGeographicElementTypeEnum::Value > Ifc4x3_rc4::IfcGeographicElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcGeographicElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcGeographicElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcGeographicElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcGeographicElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcGeographicElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcGeographicElement::declaration() const { return *IFC4X3_RC4_IfcGeographicElement_type; }
@@ -17012,7 +17012,7 @@ Ifc4x3_rc4::IfcGeometricCurveSet::IfcGeometricCurveSet(aggregate_of_instance::pt
 int Ifc4x3_rc4::IfcGeometricRepresentationContext::CoordinateSpaceDimension() const {  int v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc4::IfcGeometricRepresentationContext::setCoordinateSpaceDimension(int v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcGeometricRepresentationContext::Precision() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcGeometricRepresentationContext::setPrecision(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc4::IfcAxis2Placement* Ifc4x3_rc4::IfcGeometricRepresentationContext::WorldCoordinateSystem() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc4::IfcAxis2Placement>(true); }
 void Ifc4x3_rc4::IfcGeometricRepresentationContext::setWorldCoordinateSystem(::Ifc4x3_rc4::IfcAxis2Placement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 ::Ifc4x3_rc4::IfcDirection* Ifc4x3_rc4::IfcGeometricRepresentationContext::TrueNorth() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc4::IfcDirection>(true); }
@@ -17038,11 +17038,11 @@ Ifc4x3_rc4::IfcGeometricRepresentationItem::IfcGeometricRepresentationItem() : I
 ::Ifc4x3_rc4::IfcGeometricRepresentationContext* Ifc4x3_rc4::IfcGeometricRepresentationSubContext::ParentContext() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcGeometricRepresentationContext>(true); }
 void Ifc4x3_rc4::IfcGeometricRepresentationSubContext::setParentContext(::Ifc4x3_rc4::IfcGeometricRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcGeometricRepresentationSubContext::TargetScale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcGeometricRepresentationSubContext::setTargetScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcGeometricProjectionEnum::Value Ifc4x3_rc4::IfcGeometricRepresentationSubContext::TargetView() const {  return ::Ifc4x3_rc4::IfcGeometricProjectionEnum::FromString(*data_->getArgument(8)); }
 void Ifc4x3_rc4::IfcGeometricRepresentationSubContext::setTargetView(::Ifc4x3_rc4::IfcGeometricProjectionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcGeometricProjectionEnum::ToString(v)));data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcGeometricRepresentationSubContext::UserDefinedTargetView() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcGeometricRepresentationSubContext::setUserDefinedTargetView(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcGeometricRepresentationSubContext::declaration() const { return *IFC4X3_RC4_IfcGeometricRepresentationSubContext_type; }
@@ -17118,9 +17118,9 @@ void Ifc4x3_rc4::IfcGrid::setUAxes(aggregate_of< ::Ifc4x3_rc4::IfcGridAxis >::pt
 aggregate_of< ::Ifc4x3_rc4::IfcGridAxis >::ptr Ifc4x3_rc4::IfcGrid::VAxes() const {  aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc4::IfcGridAxis >(); }
 void Ifc4x3_rc4::IfcGrid::setVAxes(aggregate_of< ::Ifc4x3_rc4::IfcGridAxis >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(8,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcGridAxis >::ptr > Ifc4x3_rc4::IfcGrid::WAxes() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(9); return es->as< ::Ifc4x3_rc4::IfcGridAxis >(); }
-void Ifc4x3_rc4::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcGrid::setWAxes(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcGridAxis >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcGridTypeEnum::Value > Ifc4x3_rc4::IfcGrid::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcGridTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcGridTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcGrid::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcGridTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcGridTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcGrid::declaration() const { return *IFC4X3_RC4_IfcGrid_type; }
@@ -17130,7 +17130,7 @@ Ifc4x3_rc4::IfcGrid::IfcGrid(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHist
 
 // Function implementations for IfcGridAxis
 boost::optional< std::string > Ifc4x3_rc4::IfcGridAxis::AxisTag() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcGridAxis::setAxisTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc4::IfcCurve* Ifc4x3_rc4::IfcGridAxis::AxisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc4::IfcCurve>(true); }
 void Ifc4x3_rc4::IfcGridAxis::setAxisCurve(::Ifc4x3_rc4::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 bool Ifc4x3_rc4::IfcGridAxis::SameSense() const {  bool v = *data_->getArgument(2); return v; }
@@ -17181,7 +17181,7 @@ Ifc4x3_rc4::IfcHalfSpaceSolid::IfcHalfSpaceSolid(::Ifc4x3_rc4::IfcSurface* v1_Ba
 
 // Function implementations for IfcHeatExchanger
 boost::optional< ::Ifc4x3_rc4::IfcHeatExchangerTypeEnum::Value > Ifc4x3_rc4::IfcHeatExchanger::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcHeatExchangerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcHeatExchangerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcHeatExchanger::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcHeatExchangerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcHeatExchangerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcHeatExchanger::declaration() const { return *IFC4X3_RC4_IfcHeatExchanger_type; }
@@ -17201,7 +17201,7 @@ Ifc4x3_rc4::IfcHeatExchangerType::IfcHeatExchangerType(std::string v1_GlobalId,
 
 // Function implementations for IfcHumidifier
 boost::optional< ::Ifc4x3_rc4::IfcHumidifierTypeEnum::Value > Ifc4x3_rc4::IfcHumidifier::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcHumidifierTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcHumidifierTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcHumidifier::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcHumidifierTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcHumidifierTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcHumidifier::declaration() const { return *IFC4X3_RC4_IfcHumidifier_type; }
@@ -17229,11 +17229,11 @@ void Ifc4x3_rc4::IfcIShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc4::IfcIShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcIShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcIShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcIShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcIShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcIShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcIShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcIShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcIShapeProfileDef::declaration() const { return *IFC4X3_RC4_IfcIShapeProfileDef_type; }
@@ -17275,7 +17275,7 @@ Ifc4x3_rc4::IfcImpactProtectionDeviceType::IfcImpactProtectionDeviceType(std::st
 ::Ifc4x3_rc4::IfcTessellatedFaceSet* Ifc4x3_rc4::IfcIndexedColourMap::MappedTo() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc4::IfcTessellatedFaceSet>(true); }
 void Ifc4x3_rc4::IfcIndexedColourMap::setMappedTo(::Ifc4x3_rc4::IfcTessellatedFaceSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcIndexedColourMap::Opacity() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcIndexedColourMap::setOpacity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc4::IfcColourRgbList* Ifc4x3_rc4::IfcIndexedColourMap::Colours() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc4::IfcColourRgbList>(true); }
 void Ifc4x3_rc4::IfcIndexedColourMap::setColours(::Ifc4x3_rc4::IfcColourRgbList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::vector< int > /*[1:?]*/ Ifc4x3_rc4::IfcIndexedColourMap::ColourIndex() const {  std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
@@ -17291,9 +17291,9 @@ Ifc4x3_rc4::IfcIndexedColourMap::IfcIndexedColourMap(::Ifc4x3_rc4::IfcTessellate
 ::Ifc4x3_rc4::IfcCartesianPointList* Ifc4x3_rc4::IfcIndexedPolyCurve::Points() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc4::IfcCartesianPointList>(true); }
 void Ifc4x3_rc4::IfcIndexedPolyCurve::setPoints(::Ifc4x3_rc4::IfcCartesianPointList* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc4::IfcIndexedPolyCurve::Segments() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcIndexedPolyCurve::setSegments(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc4::IfcIndexedPolyCurve::SelfIntersect() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcIndexedPolyCurve::setSelfIntersect(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcIndexedPolyCurve::declaration() const { return *IFC4X3_RC4_IfcIndexedPolyCurve_type; }
@@ -17336,7 +17336,7 @@ Ifc4x3_rc4::IfcIndexedTextureMap::IfcIndexedTextureMap(aggregate_of< ::Ifc4x3_rc
 
 // Function implementations for IfcIndexedTriangleTextureMap
 boost::optional< std::vector< std::vector< int > > > Ifc4x3_rc4::IfcIndexedTriangleTextureMap::TexCoordIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcIndexedTriangleTextureMap::setTexCoordIndex(boost::optional< std::vector< std::vector< int > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcIndexedTriangleTextureMap::declaration() const { return *IFC4X3_RC4_IfcIndexedTriangleTextureMap_type; }
@@ -17346,7 +17346,7 @@ Ifc4x3_rc4::IfcIndexedTriangleTextureMap::IfcIndexedTriangleTextureMap(aggregate
 
 // Function implementations for IfcInterceptor
 boost::optional< ::Ifc4x3_rc4::IfcInterceptorTypeEnum::Value > Ifc4x3_rc4::IfcInterceptor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcInterceptorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcInterceptorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcInterceptor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcInterceptorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcInterceptorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcInterceptor::declaration() const { return *IFC4X3_RC4_IfcInterceptor_type; }
@@ -17374,13 +17374,13 @@ Ifc4x3_rc4::IfcIntersectionCurve::IfcIntersectionCurve(::Ifc4x3_rc4::IfcCurve* v
 
 // Function implementations for IfcInventory
 boost::optional< ::Ifc4x3_rc4::IfcInventoryTypeEnum::Value > Ifc4x3_rc4::IfcInventory::PredefinedType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcInventoryTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc4::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcInventoryTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcInventory::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcInventoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcInventoryTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc4::IfcActorSelect* Ifc4x3_rc4::IfcInventory::Jurisdiction() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcActorSelect>(true); }
 void Ifc4x3_rc4::IfcInventory::setJurisdiction(::Ifc4x3_rc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPerson >::ptr > Ifc4x3_rc4::IfcInventory::ResponsiblePersons() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc4::IfcPerson >(); }
-void Ifc4x3_rc4::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcInventory::setResponsiblePersons(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcInventory::LastUpdateDate() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcInventory::setLastUpdateDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc4::IfcCostValue* Ifc4x3_rc4::IfcInventory::CurrentValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc4::IfcCostValue>(true); }
 void Ifc4x3_rc4::IfcInventory::setCurrentValue(::Ifc4x3_rc4::IfcCostValue* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x3_rc4::IfcCostValue* Ifc4x3_rc4::IfcInventory::OriginalValue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc4::IfcCostValue>(true); }
@@ -17416,7 +17416,7 @@ Ifc4x3_rc4::IfcIrregularTimeSeriesValue::IfcIrregularTimeSeriesValue(std::string
 
 // Function implementations for IfcJunctionBox
 boost::optional< ::Ifc4x3_rc4::IfcJunctionBoxTypeEnum::Value > Ifc4x3_rc4::IfcJunctionBox::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcJunctionBoxTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcJunctionBoxTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcJunctionBox::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcJunctionBoxTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcJunctionBoxTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcJunctionBox::declaration() const { return *IFC4X3_RC4_IfcJunctionBox_type; }
@@ -17458,15 +17458,15 @@ Ifc4x3_rc4::IfcKerbType::IfcKerbType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 double Ifc4x3_rc4::IfcLShapeProfileDef::Depth() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcLShapeProfileDef::setDepth(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcLShapeProfileDef::Width() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcLShapeProfileDef::setWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 double Ifc4x3_rc4::IfcLShapeProfileDef::Thickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc4::IfcLShapeProfileDef::setThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcLShapeProfileDef::FilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcLShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcLShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcLShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcLShapeProfileDef::LegSlope() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcLShapeProfileDef::setLegSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcLShapeProfileDef::declaration() const { return *IFC4X3_RC4_IfcLShapeProfileDef_type; }
@@ -17476,7 +17476,7 @@ Ifc4x3_rc4::IfcLShapeProfileDef::IfcLShapeProfileDef(::Ifc4x3_rc4::IfcProfileTyp
 
 // Function implementations for IfcLaborResource
 boost::optional< ::Ifc4x3_rc4::IfcLaborResourceTypeEnum::Value > Ifc4x3_rc4::IfcLaborResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcLaborResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcLaborResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcLaborResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcLaborResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcLaborResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcLaborResource::declaration() const { return *IFC4X3_RC4_IfcLaborResource_type; }
@@ -17508,7 +17508,7 @@ Ifc4x3_rc4::IfcLagTime::IfcLagTime(boost::optional< std::string > v1_Name, boost
 
 // Function implementations for IfcLamp
 boost::optional< ::Ifc4x3_rc4::IfcLampTypeEnum::Value > Ifc4x3_rc4::IfcLamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcLampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcLampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcLamp::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcLampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcLampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcLamp::declaration() const { return *IFC4X3_RC4_IfcLamp_type; }
@@ -17530,15 +17530,15 @@ Ifc4x3_rc4::IfcLampType::IfcLampType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 std::string Ifc4x3_rc4::IfcLibraryInformation::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc4::IfcLibraryInformation::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcLibraryInformation::Version() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcLibraryInformation::setVersion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc4::IfcActorSelect* Ifc4x3_rc4::IfcLibraryInformation::Publisher() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc4::IfcActorSelect>(true); }
 void Ifc4x3_rc4::IfcLibraryInformation::setPublisher(::Ifc4x3_rc4::IfcActorSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcLibraryInformation::VersionDate() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcLibraryInformation::setVersionDate(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcLibraryInformation::Location() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcLibraryInformation::setLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcLibraryInformation::Description() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcLibraryInformation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc4::IfcRelAssociatesLibrary::list::ptr Ifc4x3_rc4::IfcLibraryInformation::LibraryInfoForObjects() const { return data_->getInverse(IFC4X3_RC4_IfcRelAssociatesLibrary_type, 5)->as<IfcRelAssociatesLibrary>(); }
 ::Ifc4x3_rc4::IfcLibraryReference::list::ptr Ifc4x3_rc4::IfcLibraryInformation::HasLibraryReferences() const { return data_->getInverse(IFC4X3_RC4_IfcLibraryReference_type, 5)->as<IfcLibraryReference>(); }
@@ -17550,9 +17550,9 @@ Ifc4x3_rc4::IfcLibraryInformation::IfcLibraryInformation(std::string v1_Name, bo
 
 // Function implementations for IfcLibraryReference
 boost::optional< std::string > Ifc4x3_rc4::IfcLibraryReference::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcLibraryReference::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcLibraryReference::Language() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcLibraryReference::setLanguage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc4::IfcLibraryInformation* Ifc4x3_rc4::IfcLibraryReference::ReferencedLibrary() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc4::IfcLibraryInformation>(true); }
 void Ifc4x3_rc4::IfcLibraryReference::setReferencedLibrary(::Ifc4x3_rc4::IfcLibraryInformation* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -17579,7 +17579,7 @@ Ifc4x3_rc4::IfcLightDistributionData::IfcLightDistributionData(double v1_MainPla
 
 // Function implementations for IfcLightFixture
 boost::optional< ::Ifc4x3_rc4::IfcLightFixtureTypeEnum::Value > Ifc4x3_rc4::IfcLightFixture::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcLightFixtureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcLightFixtureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcLightFixture::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcLightFixtureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcLightFixtureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcLightFixture::declaration() const { return *IFC4X3_RC4_IfcLightFixture_type; }
@@ -17611,13 +17611,13 @@ Ifc4x3_rc4::IfcLightIntensityDistribution::IfcLightIntensityDistribution(::Ifc4x
 
 // Function implementations for IfcLightSource
 boost::optional< std::string > Ifc4x3_rc4::IfcLightSource::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcLightSource::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 ::Ifc4x3_rc4::IfcColourRgb* Ifc4x3_rc4::IfcLightSource::LightColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc4::IfcColourRgb>(true); }
 void Ifc4x3_rc4::IfcLightSource::setLightColour(::Ifc4x3_rc4::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcLightSource::AmbientIntensity() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcLightSource::setAmbientIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcLightSource::Intensity() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcLightSource::setIntensity(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcLightSource::declaration() const { return *IFC4X3_RC4_IfcLightSource_type; }
@@ -17685,7 +17685,7 @@ Ifc4x3_rc4::IfcLightSourcePositional::IfcLightSourcePositional(boost::optional<
 ::Ifc4x3_rc4::IfcDirection* Ifc4x3_rc4::IfcLightSourceSpot::Orientation() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc4::IfcDirection>(true); }
 void Ifc4x3_rc4::IfcLightSourceSpot::setOrientation(::Ifc4x3_rc4::IfcDirection* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcLightSourceSpot::ConcentrationExponent() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcLightSourceSpot::setConcentrationExponent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 double Ifc4x3_rc4::IfcLightSourceSpot::SpreadAngle() const {  double v = *data_->getArgument(11); return v; }
 void Ifc4x3_rc4::IfcLightSourceSpot::setSpreadAngle(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 double Ifc4x3_rc4::IfcLightSourceSpot::BeamWidthAngle() const {  double v = *data_->getArgument(12); return v; }
@@ -17739,7 +17739,7 @@ Ifc4x3_rc4::IfcLinearPositioningElement::IfcLinearPositioningElement(std::string
 
 // Function implementations for IfcLiquidTerminal
 boost::optional< ::Ifc4x3_rc4::IfcLiquidTerminalTypeEnum::Value > Ifc4x3_rc4::IfcLiquidTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcLiquidTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcLiquidTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcLiquidTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcLiquidTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcLiquidTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcLiquidTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcLiquidTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcLiquidTerminal::declaration() const { return *IFC4X3_RC4_IfcLiquidTerminal_type; }
@@ -17793,15 +17793,15 @@ void Ifc4x3_rc4::IfcMapConversion::setNorthings(double v) { {IfcWrite::IfcWriteA
 double Ifc4x3_rc4::IfcMapConversion::OrthogonalHeight() const {  double v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc4::IfcMapConversion::setOrthogonalHeight(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMapConversion::XAxisAbscissa() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcMapConversion::setXAxisAbscissa(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMapConversion::XAxisOrdinate() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcMapConversion::setXAxisOrdinate(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMapConversion::Scale() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcMapConversion::setScale(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMapConversion::ScaleY() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcMapConversion::setScaleY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcMapConversion::setScaleY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMapConversion::ScaleZ() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcMapConversion::setScaleZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcMapConversion::setScaleZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMapConversion::declaration() const { return *IFC4X3_RC4_IfcMapConversion_type; }
@@ -17823,7 +17823,7 @@ Ifc4x3_rc4::IfcMappedItem::IfcMappedItem(::Ifc4x3_rc4::IfcRepresentationMap* v1_
 
 // Function implementations for IfcMarineFacility
 boost::optional< ::Ifc4x3_rc4::IfcMarineFacilityTypeEnum::Value > Ifc4x3_rc4::IfcMarineFacility::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcMarineFacilityTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcMarineFacility::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMarineFacilityTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMarineFacilityTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcMarineFacility::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMarineFacilityTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMarineFacilityTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMarineFacility::declaration() const { return *IFC4X3_RC4_IfcMarineFacility_type; }
@@ -17835,9 +17835,9 @@ Ifc4x3_rc4::IfcMarineFacility::IfcMarineFacility(std::string v1_GlobalId, ::Ifc4
 std::string Ifc4x3_rc4::IfcMaterial::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc4::IfcMaterial::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterial::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcMaterial::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterial::Category() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcMaterial::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 ::Ifc4x3_rc4::IfcMaterialDefinitionRepresentation::list::ptr Ifc4x3_rc4::IfcMaterial::HasRepresentation() const { return data_->getInverse(IFC4X3_RC4_IfcMaterialDefinitionRepresentation_type, 3)->as<IfcMaterialDefinitionRepresentation>(); }
 ::Ifc4x3_rc4::IfcMaterialRelationship::list::ptr Ifc4x3_rc4::IfcMaterial::IsRelatedWith() const { return data_->getInverse(IFC4X3_RC4_IfcMaterialRelationship_type, 3)->as<IfcMaterialRelationship>(); }
@@ -17862,15 +17862,15 @@ Ifc4x3_rc4::IfcMaterialClassificationRelationship::IfcMaterialClassificationRela
 
 // Function implementations for IfcMaterialConstituent
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialConstituent::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcMaterialConstituent::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialConstituent::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcMaterialConstituent::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc4::IfcMaterial* Ifc4x3_rc4::IfcMaterialConstituent::Material() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc4::IfcMaterial>(true); }
 void Ifc4x3_rc4::IfcMaterialConstituent::setMaterial(::Ifc4x3_rc4::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMaterialConstituent::Fraction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcMaterialConstituent::setFraction(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialConstituent::Category() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcMaterialConstituent::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc4::IfcMaterialConstituentSet::list::ptr Ifc4x3_rc4::IfcMaterialConstituent::ToMaterialConstituentSet() const { return data_->getInverse(IFC4X3_RC4_IfcMaterialConstituentSet_type, 2)->as<IfcMaterialConstituentSet>(); }
 
@@ -17881,11 +17881,11 @@ Ifc4x3_rc4::IfcMaterialConstituent::IfcMaterialConstituent(boost::optional< std:
 
 // Function implementations for IfcMaterialConstituentSet
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialConstituentSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcMaterialConstituentSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialConstituentSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcMaterialConstituentSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcMaterialConstituent >::ptr > Ifc4x3_rc4::IfcMaterialConstituentSet::MaterialConstituents() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc4::IfcMaterialConstituent >(); }
-void Ifc4x3_rc4::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcMaterialConstituentSet::setMaterialConstituents(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcMaterialConstituent >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMaterialConstituentSet::declaration() const { return *IFC4X3_RC4_IfcMaterialConstituentSet_type; }
@@ -17920,15 +17920,15 @@ void Ifc4x3_rc4::IfcMaterialLayer::setMaterial(::Ifc4x3_rc4::IfcMaterial* v) { {
 double Ifc4x3_rc4::IfcMaterialLayer::LayerThickness() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcMaterialLayer::setLayerThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< boost::logic::tribool > Ifc4x3_rc4::IfcMaterialLayer::IsVentilated() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } boost::logic::tribool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcMaterialLayer::setIsVentilated(boost::optional< boost::logic::tribool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialLayer::Name() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcMaterialLayer::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialLayer::Description() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcMaterialLayer::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialLayer::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcMaterialLayer::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x3_rc4::IfcMaterialLayer::Priority() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcMaterialLayer::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc4::IfcMaterialLayerSet::list::ptr Ifc4x3_rc4::IfcMaterialLayer::ToMaterialLayerSet() const { return data_->getInverse(IFC4X3_RC4_IfcMaterialLayerSet_type, 0)->as<IfcMaterialLayerSet>(); }
 
@@ -17941,9 +17941,9 @@ Ifc4x3_rc4::IfcMaterialLayer::IfcMaterialLayer(::Ifc4x3_rc4::IfcMaterial* v1_Mat
 aggregate_of< ::Ifc4x3_rc4::IfcMaterialLayer >::ptr Ifc4x3_rc4::IfcMaterialLayerSet::MaterialLayers() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x3_rc4::IfcMaterialLayer >(); }
 void Ifc4x3_rc4::IfcMaterialLayerSet::setMaterialLayers(aggregate_of< ::Ifc4x3_rc4::IfcMaterialLayer >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialLayerSet::LayerSetName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcMaterialLayerSet::setLayerSetName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialLayerSet::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcMaterialLayerSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMaterialLayerSet::declaration() const { return *IFC4X3_RC4_IfcMaterialLayerSet_type; }
@@ -17961,7 +17961,7 @@ void Ifc4x3_rc4::IfcMaterialLayerSetUsage::setDirectionSense(::Ifc4x3_rc4::IfcDi
 double Ifc4x3_rc4::IfcMaterialLayerSetUsage::OffsetFromReferenceLine() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcMaterialLayerSetUsage::setOffsetFromReferenceLine(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMaterialLayerSetUsage::ReferenceExtent() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcMaterialLayerSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMaterialLayerSetUsage::declaration() const { return *IFC4X3_RC4_IfcMaterialLayerSetUsage_type; }
@@ -17993,17 +17993,17 @@ Ifc4x3_rc4::IfcMaterialList::IfcMaterialList(aggregate_of< ::Ifc4x3_rc4::IfcMate
 
 // Function implementations for IfcMaterialProfile
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialProfile::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcMaterialProfile::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialProfile::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcMaterialProfile::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 ::Ifc4x3_rc4::IfcMaterial* Ifc4x3_rc4::IfcMaterialProfile::Material() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(2)))->as<::Ifc4x3_rc4::IfcMaterial>(true); }
 void Ifc4x3_rc4::IfcMaterialProfile::setMaterial(::Ifc4x3_rc4::IfcMaterial* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcProfileDef* Ifc4x3_rc4::IfcMaterialProfile::Profile() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcProfileDef>(true); }
 void Ifc4x3_rc4::IfcMaterialProfile::setProfile(::Ifc4x3_rc4::IfcProfileDef* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc4::IfcMaterialProfile::Priority() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcMaterialProfile::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialProfile::Category() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcMaterialProfile::setCategory(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc4::IfcMaterialProfileSet::list::ptr Ifc4x3_rc4::IfcMaterialProfile::ToMaterialProfileSet() const { return data_->getInverse(IFC4X3_RC4_IfcMaterialProfileSet_type, 2)->as<IfcMaterialProfileSet>(); }
 
@@ -18014,9 +18014,9 @@ Ifc4x3_rc4::IfcMaterialProfile::IfcMaterialProfile(boost::optional< std::string
 
 // Function implementations for IfcMaterialProfileSet
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialProfileSet::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcMaterialProfileSet::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialProfileSet::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcMaterialProfileSet::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc4::IfcMaterialProfile >::ptr Ifc4x3_rc4::IfcMaterialProfileSet::MaterialProfiles() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc4::IfcMaterialProfile >(); }
 void Ifc4x3_rc4::IfcMaterialProfileSet::setMaterialProfiles(aggregate_of< ::Ifc4x3_rc4::IfcMaterialProfile >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcCompositeProfileDef* Ifc4x3_rc4::IfcMaterialProfileSet::CompositeProfile() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcCompositeProfileDef>(true); }
@@ -18032,9 +18032,9 @@ Ifc4x3_rc4::IfcMaterialProfileSet::IfcMaterialProfileSet(boost::optional< std::s
 ::Ifc4x3_rc4::IfcMaterialProfileSet* Ifc4x3_rc4::IfcMaterialProfileSetUsage::ForProfileSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc4::IfcMaterialProfileSet>(true); }
 void Ifc4x3_rc4::IfcMaterialProfileSetUsage::setForProfileSet(::Ifc4x3_rc4::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< int > Ifc4x3_rc4::IfcMaterialProfileSetUsage::CardinalPoint() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } int v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcMaterialProfileSetUsage::setCardinalPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMaterialProfileSetUsage::ReferenceExtent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcMaterialProfileSetUsage::setReferenceExtent(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMaterialProfileSetUsage::declaration() const { return *IFC4X3_RC4_IfcMaterialProfileSetUsage_type; }
@@ -18046,7 +18046,7 @@ Ifc4x3_rc4::IfcMaterialProfileSetUsage::IfcMaterialProfileSetUsage(::Ifc4x3_rc4:
 ::Ifc4x3_rc4::IfcMaterialProfileSet* Ifc4x3_rc4::IfcMaterialProfileSetUsageTapering::ForProfileEndSet() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcMaterialProfileSet>(true); }
 void Ifc4x3_rc4::IfcMaterialProfileSetUsageTapering::setForProfileEndSet(::Ifc4x3_rc4::IfcMaterialProfileSet* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc4::IfcMaterialProfileSetUsageTapering::CardinalEndPoint() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcMaterialProfileSetUsageTapering::setCardinalEndPoint(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMaterialProfileSetUsageTapering::declaration() const { return *IFC4X3_RC4_IfcMaterialProfileSetUsageTapering_type; }
@@ -18080,7 +18080,7 @@ void Ifc4x3_rc4::IfcMaterialRelationship::setRelatingMaterial(::Ifc4x3_rc4::IfcM
 aggregate_of< ::Ifc4x3_rc4::IfcMaterial >::ptr Ifc4x3_rc4::IfcMaterialRelationship::RelatedMaterials() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc4::IfcMaterial >(); }
 void Ifc4x3_rc4::IfcMaterialRelationship::setRelatedMaterials(aggregate_of< ::Ifc4x3_rc4::IfcMaterial >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMaterialRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcMaterialRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMaterialRelationship::declaration() const { return *IFC4X3_RC4_IfcMaterialRelationship_type; }
@@ -18111,11 +18111,11 @@ Ifc4x3_rc4::IfcMeasureWithUnit::IfcMeasureWithUnit(::Ifc4x3_rc4::IfcValue* v1_Va
 
 // Function implementations for IfcMechanicalFastener
 boost::optional< double > Ifc4x3_rc4::IfcMechanicalFastener::NominalDiameter() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcMechanicalFastener::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMechanicalFastener::NominalLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcMechanicalFastener::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcMechanicalFastenerTypeEnum::Value > Ifc4x3_rc4::IfcMechanicalFastener::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMechanicalFastenerTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcMechanicalFastener::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMechanicalFastenerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMechanicalFastenerTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMechanicalFastener::declaration() const { return *IFC4X3_RC4_IfcMechanicalFastener_type; }
@@ -18127,9 +18127,9 @@ Ifc4x3_rc4::IfcMechanicalFastener::IfcMechanicalFastener(std::string v1_GlobalId
 ::Ifc4x3_rc4::IfcMechanicalFastenerTypeEnum::Value Ifc4x3_rc4::IfcMechanicalFastenerType::PredefinedType() const {  return ::Ifc4x3_rc4::IfcMechanicalFastenerTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc4::IfcMechanicalFastenerType::setPredefinedType(::Ifc4x3_rc4::IfcMechanicalFastenerTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcMechanicalFastenerTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMechanicalFastenerType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcMechanicalFastenerType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcMechanicalFastenerType::NominalLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcMechanicalFastenerType::setNominalLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMechanicalFastenerType::declaration() const { return *IFC4X3_RC4_IfcMechanicalFastenerType_type; }
@@ -18139,7 +18139,7 @@ Ifc4x3_rc4::IfcMechanicalFastenerType::IfcMechanicalFastenerType(std::string v1_
 
 // Function implementations for IfcMedicalDevice
 boost::optional< ::Ifc4x3_rc4::IfcMedicalDeviceTypeEnum::Value > Ifc4x3_rc4::IfcMedicalDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcMedicalDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMedicalDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcMedicalDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMedicalDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMedicalDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMedicalDevice::declaration() const { return *IFC4X3_RC4_IfcMedicalDevice_type; }
@@ -18159,7 +18159,7 @@ Ifc4x3_rc4::IfcMedicalDeviceType::IfcMedicalDeviceType(std::string v1_GlobalId,
 
 // Function implementations for IfcMember
 boost::optional< ::Ifc4x3_rc4::IfcMemberTypeEnum::Value > Ifc4x3_rc4::IfcMember::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcMemberTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcMember::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMemberTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcMember::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMemberTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMemberTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMember::declaration() const { return *IFC4X3_RC4_IfcMember_type; }
@@ -18189,7 +18189,7 @@ Ifc4x3_rc4::IfcMemberType::IfcMemberType(std::string v1_GlobalId, ::Ifc4x3_rc4::
 ::Ifc4x3_rc4::IfcBenchmarkEnum::Value Ifc4x3_rc4::IfcMetric::Benchmark() const {  return ::Ifc4x3_rc4::IfcBenchmarkEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc4::IfcMetric::setBenchmark(::Ifc4x3_rc4::IfcBenchmarkEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcBenchmarkEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcMetric::ValueSource() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcMetric::setValueSource(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc4::IfcMetricValueSelect* Ifc4x3_rc4::IfcMetric::DataValue() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc4::IfcMetricValueSelect>(true); }
 void Ifc4x3_rc4::IfcMetric::setDataValue(::Ifc4x3_rc4::IfcMetricValueSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 ::Ifc4x3_rc4::IfcReference* Ifc4x3_rc4::IfcMetric::ReferencePath() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(10)))->as<::Ifc4x3_rc4::IfcReference>(true); }
@@ -18211,7 +18211,7 @@ Ifc4x3_rc4::IfcMirroredProfileDef::IfcMirroredProfileDef(::Ifc4x3_rc4::IfcProfil
 
 // Function implementations for IfcMobileTelecommunicationsAppliance
 boost::optional< ::Ifc4x3_rc4::IfcMobileTelecommunicationsApplianceTypeEnum::Value > Ifc4x3_rc4::IfcMobileTelecommunicationsAppliance::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcMobileTelecommunicationsApplianceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcMobileTelecommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMobileTelecommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMobileTelecommunicationsApplianceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcMobileTelecommunicationsAppliance::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMobileTelecommunicationsApplianceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMobileTelecommunicationsApplianceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMobileTelecommunicationsAppliance::declaration() const { return *IFC4X3_RC4_IfcMobileTelecommunicationsAppliance_type; }
@@ -18241,7 +18241,7 @@ Ifc4x3_rc4::IfcMonetaryUnit::IfcMonetaryUnit(std::string v1_Currency) : IfcUtil:
 
 // Function implementations for IfcMooringDevice
 boost::optional< ::Ifc4x3_rc4::IfcMooringDeviceTypeEnum::Value > Ifc4x3_rc4::IfcMooringDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcMooringDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcMooringDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMooringDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMooringDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcMooringDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMooringDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMooringDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMooringDevice::declaration() const { return *IFC4X3_RC4_IfcMooringDevice_type; }
@@ -18261,7 +18261,7 @@ Ifc4x3_rc4::IfcMooringDeviceType::IfcMooringDeviceType(std::string v1_GlobalId,
 
 // Function implementations for IfcMotorConnection
 boost::optional< ::Ifc4x3_rc4::IfcMotorConnectionTypeEnum::Value > Ifc4x3_rc4::IfcMotorConnection::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcMotorConnectionTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMotorConnectionTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcMotorConnection::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcMotorConnectionTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcMotorConnectionTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcMotorConnection::declaration() const { return *IFC4X3_RC4_IfcMotorConnection_type; }
@@ -18293,7 +18293,7 @@ Ifc4x3_rc4::IfcNamedUnit::IfcNamedUnit(::Ifc4x3_rc4::IfcDimensionalExponents* v1
 
 // Function implementations for IfcNavigationElement
 boost::optional< ::Ifc4x3_rc4::IfcNavigationElementTypeEnum::Value > Ifc4x3_rc4::IfcNavigationElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcNavigationElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcNavigationElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcNavigationElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcNavigationElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcNavigationElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcNavigationElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcNavigationElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcNavigationElement::declaration() const { return *IFC4X3_RC4_IfcNavigationElement_type; }
@@ -18313,7 +18313,7 @@ Ifc4x3_rc4::IfcNavigationElementType::IfcNavigationElementType(std::string v1_Gl
 
 // Function implementations for IfcObject
 boost::optional< std::string > Ifc4x3_rc4::IfcObject::ObjectType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcObject::setObjectType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc4::IfcRelDefinesByObject::list::ptr Ifc4x3_rc4::IfcObject::IsDeclaredBy() const { return data_->getInverse(IFC4X3_RC4_IfcRelDefinesByObject_type, 4)->as<IfcRelDefinesByObject>(); }
 ::Ifc4x3_rc4::IfcRelDefinesByObject::list::ptr Ifc4x3_rc4::IfcObject::Declares() const { return data_->getInverse(IFC4X3_RC4_IfcRelDefinesByObject_type, 5)->as<IfcRelDefinesByObject>(); }
@@ -18353,13 +18353,13 @@ Ifc4x3_rc4::IfcObjectPlacement::IfcObjectPlacement(::Ifc4x3_rc4::IfcObjectPlacem
 
 // Function implementations for IfcObjective
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcConstraint >::ptr > Ifc4x3_rc4::IfcObjective::BenchmarkValues() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc4::IfcConstraint >(); }
-void Ifc4x3_rc4::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcObjective::setBenchmarkValues(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcConstraint >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcLogicalOperatorEnum::Value > Ifc4x3_rc4::IfcObjective::LogicalAggregator() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcLogicalOperatorEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x3_rc4::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcLogicalOperatorEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcObjective::setLogicalAggregator(boost::optional< ::Ifc4x3_rc4::IfcLogicalOperatorEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcLogicalOperatorEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc4::IfcObjectiveEnum::Value Ifc4x3_rc4::IfcObjective::ObjectiveQualifier() const {  return ::Ifc4x3_rc4::IfcObjectiveEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc4::IfcObjective::setObjectiveQualifier(::Ifc4x3_rc4::IfcObjectiveEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcObjectiveEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcObjective::UserDefinedQualifier() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcObjective::setUserDefinedQualifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcObjective::declaration() const { return *IFC4X3_RC4_IfcObjective_type; }
@@ -18369,7 +18369,7 @@ Ifc4x3_rc4::IfcObjective::IfcObjective(std::string v1_Name, boost::optional< std
 
 // Function implementations for IfcOccupant
 boost::optional< ::Ifc4x3_rc4::IfcOccupantTypeEnum::Value > Ifc4x3_rc4::IfcOccupant::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcOccupantTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc4::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcOccupantTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcOccupant::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcOccupantTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcOccupantTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcOccupant::declaration() const { return *IFC4X3_RC4_IfcOccupant_type; }
@@ -18417,7 +18417,7 @@ Ifc4x3_rc4::IfcOffsetCurve3D::IfcOffsetCurve3D(::Ifc4x3_rc4::IfcCurve* v1_BasisC
 aggregate_of< ::Ifc4x3_rc4::IfcPointByDistanceExpression >::ptr Ifc4x3_rc4::IfcOffsetCurveByDistances::OffsetValues() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc4::IfcPointByDistanceExpression >(); }
 void Ifc4x3_rc4::IfcOffsetCurveByDistances::setOffsetValues(aggregate_of< ::Ifc4x3_rc4::IfcPointByDistanceExpression >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcOffsetCurveByDistances::Tag() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcOffsetCurveByDistances::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcOffsetCurveByDistances::declaration() const { return *IFC4X3_RC4_IfcOffsetCurveByDistances_type; }
@@ -18433,7 +18433,7 @@ void Ifc4x3_rc4::IfcOpenCrossProfileDef::setWidths(std::vector< double > /*[1:?]
 std::vector< double > /*[1:?]*/ Ifc4x3_rc4::IfcOpenCrossProfileDef::Slopes() const {  std::vector< double > /*[1:?]*/ v = *data_->getArgument(4); return v; }
 void Ifc4x3_rc4::IfcOpenCrossProfileDef::setSlopes(std::vector< double > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[2:?]*/ > Ifc4x3_rc4::IfcOpenCrossProfileDef::Tags() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[2:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcOpenCrossProfileDef::setTags(boost::optional< std::vector< std::string > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcOpenCrossProfileDef::setTags(boost::optional< std::vector< std::string > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcOpenCrossProfileDef::declaration() const { return *IFC4X3_RC4_IfcOpenCrossProfileDef_type; }
@@ -18451,7 +18451,7 @@ Ifc4x3_rc4::IfcOpenShell::IfcOpenShell(aggregate_of< ::Ifc4x3_rc4::IfcFace >::pt
 
 // Function implementations for IfcOpeningElement
 boost::optional< ::Ifc4x3_rc4::IfcOpeningElementTypeEnum::Value > Ifc4x3_rc4::IfcOpeningElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcOpeningElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcOpeningElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcOpeningElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcOpeningElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcOpeningElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc4::IfcRelFillsElement::list::ptr Ifc4x3_rc4::IfcOpeningElement::HasFillings() const { return data_->getInverse(IFC4X3_RC4_IfcRelFillsElement_type, 4)->as<IfcRelFillsElement>(); }
 
@@ -18470,15 +18470,15 @@ Ifc4x3_rc4::IfcOpeningStandardCase::IfcOpeningStandardCase(std::string v1_Global
 
 // Function implementations for IfcOrganization
 boost::optional< std::string > Ifc4x3_rc4::IfcOrganization::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcOrganization::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 std::string Ifc4x3_rc4::IfcOrganization::Name() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcOrganization::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcOrganization::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcOrganization::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcActorRole >::ptr > Ifc4x3_rc4::IfcOrganization::Roles() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc4::IfcActorRole >(); }
-void Ifc4x3_rc4::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(3,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAddress >::ptr > Ifc4x3_rc4::IfcOrganization::Addresses() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x3_rc4::IfcAddress >(); }
-void Ifc4x3_rc4::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcOrganization::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc4::IfcOrganizationRelationship::list::ptr Ifc4x3_rc4::IfcOrganization::IsRelatedBy() const { return data_->getInverse(IFC4X3_RC4_IfcOrganizationRelationship_type, 3)->as<IfcOrganizationRelationship>(); }
 ::Ifc4x3_rc4::IfcOrganizationRelationship::list::ptr Ifc4x3_rc4::IfcOrganization::Relates() const { return data_->getInverse(IFC4X3_RC4_IfcOrganizationRelationship_type, 2)->as<IfcOrganizationRelationship>(); }
@@ -18523,7 +18523,7 @@ Ifc4x3_rc4::IfcOuterBoundaryCurve::IfcOuterBoundaryCurve(aggregate_of< ::Ifc4x3_
 
 // Function implementations for IfcOutlet
 boost::optional< ::Ifc4x3_rc4::IfcOutletTypeEnum::Value > Ifc4x3_rc4::IfcOutlet::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcOutletTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcOutletTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcOutlet::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcOutletTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcOutletTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcOutlet::declaration() const { return *IFC4X3_RC4_IfcOutlet_type; }
@@ -18547,11 +18547,11 @@ void Ifc4x3_rc4::IfcOwnerHistory::setOwningUser(::Ifc4x3_rc4::IfcPersonAndOrgani
 ::Ifc4x3_rc4::IfcApplication* Ifc4x3_rc4::IfcOwnerHistory::OwningApplication() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc4::IfcApplication>(true); }
 void Ifc4x3_rc4::IfcOwnerHistory::setOwningApplication(::Ifc4x3_rc4::IfcApplication* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcStateEnum::Value > Ifc4x3_rc4::IfcOwnerHistory::State() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcStateEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc4::IfcOwnerHistory::setState(boost::optional< ::Ifc4x3_rc4::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcStateEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcOwnerHistory::setState(boost::optional< ::Ifc4x3_rc4::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcStateEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcChangeActionEnum::Value > Ifc4x3_rc4::IfcOwnerHistory::ChangeAction() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcChangeActionEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x3_rc4::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x3_rc4::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcChangeActionEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcOwnerHistory::setChangeAction(boost::optional< ::Ifc4x3_rc4::IfcChangeActionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcChangeActionEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc4::IfcOwnerHistory::LastModifiedDate() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcOwnerHistory::setLastModifiedDate(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc4::IfcPersonAndOrganization* Ifc4x3_rc4::IfcOwnerHistory::LastModifyingUser() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc4::IfcPersonAndOrganization>(true); }
 void Ifc4x3_rc4::IfcOwnerHistory::setLastModifyingUser(::Ifc4x3_rc4::IfcPersonAndOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x3_rc4::IfcApplication* Ifc4x3_rc4::IfcOwnerHistory::LastModifyingApplication() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcApplication>(true); }
@@ -18587,7 +18587,7 @@ Ifc4x3_rc4::IfcPath::IfcPath(aggregate_of< ::Ifc4x3_rc4::IfcOrientedEdge >::ptr
 
 // Function implementations for IfcPavement
 boost::optional< ::Ifc4x3_rc4::IfcPavementTypeEnum::Value > Ifc4x3_rc4::IfcPavement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcPavementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcPavement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPavementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPavementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcPavement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPavementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPavementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPavement::declaration() const { return *IFC4X3_RC4_IfcPavement_type; }
@@ -18621,7 +18621,7 @@ Ifc4x3_rc4::IfcPcurve::IfcPcurve(::Ifc4x3_rc4::IfcSurface* v1_BasisSurface, ::If
 std::string Ifc4x3_rc4::IfcPerformanceHistory::LifeCyclePhase() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcPerformanceHistory::setLifeCyclePhase(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcPerformanceHistoryTypeEnum::Value > Ifc4x3_rc4::IfcPerformanceHistory::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcPerformanceHistoryTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc4::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPerformanceHistoryTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcPerformanceHistory::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPerformanceHistoryTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPerformanceHistoryTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPerformanceHistory::declaration() const { return *IFC4X3_RC4_IfcPerformanceHistory_type; }
@@ -18635,9 +18635,9 @@ void Ifc4x3_rc4::IfcPermeableCoveringProperties::setOperationType(::Ifc4x3_rc4::
 ::Ifc4x3_rc4::IfcWindowPanelPositionEnum::Value Ifc4x3_rc4::IfcPermeableCoveringProperties::PanelPosition() const {  return ::Ifc4x3_rc4::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc4::IfcPermeableCoveringProperties::setPanelPosition(::Ifc4x3_rc4::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcPermeableCoveringProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcPermeableCoveringProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcPermeableCoveringProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcPermeableCoveringProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcShapeAspect* Ifc4x3_rc4::IfcPermeableCoveringProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc4::IfcShapeAspect>(true); }
 void Ifc4x3_rc4::IfcPermeableCoveringProperties::setShapeAspectStyle(::Ifc4x3_rc4::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -18649,11 +18649,11 @@ Ifc4x3_rc4::IfcPermeableCoveringProperties::IfcPermeableCoveringProperties(std::
 
 // Function implementations for IfcPermit
 boost::optional< ::Ifc4x3_rc4::IfcPermitTypeEnum::Value > Ifc4x3_rc4::IfcPermit::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcPermitTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc4::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPermitTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcPermit::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPermitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPermitTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPermit::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcPermit::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPermit::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcPermit::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPermit::declaration() const { return *IFC4X3_RC4_IfcPermit_type; }
@@ -18663,21 +18663,21 @@ Ifc4x3_rc4::IfcPermit::IfcPermit(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwner
 
 // Function implementations for IfcPerson
 boost::optional< std::string > Ifc4x3_rc4::IfcPerson::Identification() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcPerson::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPerson::FamilyName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcPerson::setFamilyName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPerson::GivenName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcPerson::setGivenName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcPerson::MiddleNames() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcPerson::setMiddleNames(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcPerson::PrefixTitles() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcPerson::setPrefixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcPerson::SuffixTitles() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcPerson::setSuffixTitles(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcActorRole >::ptr > Ifc4x3_rc4::IfcPerson::Roles() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc4::IfcActorRole >(); }
-void Ifc4x3_rc4::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcPerson::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAddress >::ptr > Ifc4x3_rc4::IfcPerson::Addresses() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc4::IfcAddress >(); }
-void Ifc4x3_rc4::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcPerson::setAddresses(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcAddress >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc4::IfcPersonAndOrganization::list::ptr Ifc4x3_rc4::IfcPerson::EngagedIn() const { return data_->getInverse(IFC4X3_RC4_IfcPersonAndOrganization_type, 0)->as<IfcPersonAndOrganization>(); }
 
@@ -18692,7 +18692,7 @@ void Ifc4x3_rc4::IfcPersonAndOrganization::setThePerson(::Ifc4x3_rc4::IfcPerson*
 ::Ifc4x3_rc4::IfcOrganization* Ifc4x3_rc4::IfcPersonAndOrganization::TheOrganization() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc4::IfcOrganization>(true); }
 void Ifc4x3_rc4::IfcPersonAndOrganization::setTheOrganization(::Ifc4x3_rc4::IfcOrganization* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcActorRole >::ptr > Ifc4x3_rc4::IfcPersonAndOrganization::Roles() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc4::IfcActorRole >(); }
-void Ifc4x3_rc4::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcPersonAndOrganization::setRoles(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcActorRole >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPersonAndOrganization::declaration() const { return *IFC4X3_RC4_IfcPersonAndOrganization_type; }
@@ -18706,9 +18706,9 @@ void Ifc4x3_rc4::IfcPhysicalComplexQuantity::setHasQuantities(aggregate_of< ::If
 std::string Ifc4x3_rc4::IfcPhysicalComplexQuantity::Discrimination() const {  std::string v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcPhysicalComplexQuantity::setDiscrimination(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPhysicalComplexQuantity::Quality() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcPhysicalComplexQuantity::setQuality(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPhysicalComplexQuantity::Usage() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcPhysicalComplexQuantity::setUsage(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPhysicalComplexQuantity::declaration() const { return *IFC4X3_RC4_IfcPhysicalComplexQuantity_type; }
@@ -18720,7 +18720,7 @@ Ifc4x3_rc4::IfcPhysicalComplexQuantity::IfcPhysicalComplexQuantity(std::string v
 std::string Ifc4x3_rc4::IfcPhysicalQuantity::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc4::IfcPhysicalQuantity::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPhysicalQuantity::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcPhysicalQuantity::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc4::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc4::IfcPhysicalQuantity::HasExternalReferences() const { return data_->getInverse(IFC4X3_RC4_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc4::IfcPhysicalComplexQuantity::list::ptr Ifc4x3_rc4::IfcPhysicalQuantity::PartOfComplex() const { return data_->getInverse(IFC4X3_RC4_IfcPhysicalComplexQuantity_type, 2)->as<IfcPhysicalComplexQuantity>(); }
@@ -18742,9 +18742,9 @@ Ifc4x3_rc4::IfcPhysicalSimpleQuantity::IfcPhysicalSimpleQuantity(std::string v1_
 
 // Function implementations for IfcPile
 boost::optional< ::Ifc4x3_rc4::IfcPileTypeEnum::Value > Ifc4x3_rc4::IfcPile::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcPileTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcPile::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPileTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcPile::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPileTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPileTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcPileConstructionEnum::Value > Ifc4x3_rc4::IfcPile::ConstructionType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcPileConstructionEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcPile::setConstructionType(boost::optional< ::Ifc4x3_rc4::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPileConstructionEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcPile::setConstructionType(boost::optional< ::Ifc4x3_rc4::IfcPileConstructionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPileConstructionEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPile::declaration() const { return *IFC4X3_RC4_IfcPile_type; }
@@ -18764,7 +18764,7 @@ Ifc4x3_rc4::IfcPileType::IfcPileType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcPipeFitting
 boost::optional< ::Ifc4x3_rc4::IfcPipeFittingTypeEnum::Value > Ifc4x3_rc4::IfcPipeFitting::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcPipeFittingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPipeFittingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcPipeFitting::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPipeFittingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPipeFittingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPipeFitting::declaration() const { return *IFC4X3_RC4_IfcPipeFitting_type; }
@@ -18784,7 +18784,7 @@ Ifc4x3_rc4::IfcPipeFittingType::IfcPipeFittingType(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcPipeSegment
 boost::optional< ::Ifc4x3_rc4::IfcPipeSegmentTypeEnum::Value > Ifc4x3_rc4::IfcPipeSegment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcPipeSegmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPipeSegmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcPipeSegment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPipeSegmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPipeSegmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPipeSegment::declaration() const { return *IFC4X3_RC4_IfcPipeSegment_type; }
@@ -18868,7 +18868,7 @@ Ifc4x3_rc4::IfcPlant::IfcPlant(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHi
 
 // Function implementations for IfcPlate
 boost::optional< ::Ifc4x3_rc4::IfcPlateTypeEnum::Value > Ifc4x3_rc4::IfcPlate::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcPlateTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPlateTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcPlate::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPlateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPlateTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPlate::declaration() const { return *IFC4X3_RC4_IfcPlate_type; }
@@ -18906,11 +18906,11 @@ Ifc4x3_rc4::IfcPoint::IfcPoint() : IfcGeometricRepresentationItem((IfcEntityInst
 ::Ifc4x3_rc4::IfcCurveMeasureSelect* Ifc4x3_rc4::IfcPointByDistanceExpression::DistanceAlong() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc4::IfcCurveMeasureSelect>(true); }
 void Ifc4x3_rc4::IfcPointByDistanceExpression::setDistanceAlong(::Ifc4x3_rc4::IfcCurveMeasureSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcPointByDistanceExpression::OffsetLateral() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcPointByDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcPointByDistanceExpression::setOffsetLateral(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcPointByDistanceExpression::OffsetVertical() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcPointByDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcPointByDistanceExpression::setOffsetVertical(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcPointByDistanceExpression::OffsetLongitudinal() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcPointByDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcPointByDistanceExpression::setOffsetLongitudinal(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc4::IfcCurve* Ifc4x3_rc4::IfcPointByDistanceExpression::BasisCurve() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc4::IfcCurve>(true); }
 void Ifc4x3_rc4::IfcPointByDistanceExpression::setBasisCurve(::Ifc4x3_rc4::IfcCurve* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -18970,11 +18970,11 @@ Ifc4x3_rc4::IfcPolygonalBoundedHalfSpace::IfcPolygonalBoundedHalfSpace(::Ifc4x3_
 
 // Function implementations for IfcPolygonalFaceSet
 boost::optional< bool > Ifc4x3_rc4::IfcPolygonalFaceSet::Closed() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcPolygonalFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc4::IfcIndexedPolygonalFace >::ptr Ifc4x3_rc4::IfcPolygonalFaceSet::Faces() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc4::IfcIndexedPolygonalFace >(); }
 void Ifc4x3_rc4::IfcPolygonalFaceSet::setFaces(aggregate_of< ::Ifc4x3_rc4::IfcIndexedPolygonalFace >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc4::IfcPolygonalFaceSet::PnIndex() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcPolygonalFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPolygonalFaceSet::declaration() const { return *IFC4X3_RC4_IfcPolygonalFaceSet_type; }
@@ -18996,11 +18996,11 @@ Ifc4x3_rc4::IfcPolyline::IfcPolyline(aggregate_of< ::Ifc4x3_rc4::IfcCartesianPoi
 ::Ifc4x3_rc4::IfcPlacement* Ifc4x3_rc4::IfcPolynomialCurve::Position() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc4::IfcPlacement>(true); }
 void Ifc4x3_rc4::IfcPolynomialCurve::setPosition(::Ifc4x3_rc4::IfcPlacement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::vector< double > /*[2:?]*/ > Ifc4x3_rc4::IfcPolynomialCurve::CoefficientsX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< double > /*[2:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcPolynomialCurve::setCoefficientsX(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcPolynomialCurve::setCoefficientsX(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[2:?]*/ > Ifc4x3_rc4::IfcPolynomialCurve::CoefficientsY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[2:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcPolynomialCurve::setCoefficientsY(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcPolynomialCurve::setCoefficientsY(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< double > /*[2:?]*/ > Ifc4x3_rc4::IfcPolynomialCurve::CoefficientsZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< double > /*[2:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcPolynomialCurve::setCoefficientsZ(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcPolynomialCurve::setCoefficientsZ(boost::optional< std::vector< double > /*[2:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPolynomialCurve::declaration() const { return *IFC4X3_RC4_IfcPolynomialCurve_type; }
@@ -19031,19 +19031,19 @@ Ifc4x3_rc4::IfcPositioningElement::IfcPositioningElement(std::string v1_GlobalId
 
 // Function implementations for IfcPostalAddress
 boost::optional< std::string > Ifc4x3_rc4::IfcPostalAddress::InternalLocation() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcPostalAddress::setInternalLocation(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcPostalAddress::AddressLines() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcPostalAddress::setAddressLines(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPostalAddress::PostalBox() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcPostalAddress::setPostalBox(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPostalAddress::Town() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcPostalAddress::setTown(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPostalAddress::Region() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcPostalAddress::setRegion(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPostalAddress::PostalCode() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcPostalAddress::setPostalCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPostalAddress::Country() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcPostalAddress::setCountry(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPostalAddress::declaration() const { return *IFC4X3_RC4_IfcPostalAddress_type; }
@@ -19113,11 +19113,11 @@ Ifc4x3_rc4::IfcPresentationItem::IfcPresentationItem() : IfcUtil::IfcBaseEntity(
 std::string Ifc4x3_rc4::IfcPresentationLayerAssignment::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc4::IfcPresentationLayerAssignment::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPresentationLayerAssignment::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcPresentationLayerAssignment::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of_instance::ptr Ifc4x3_rc4::IfcPresentationLayerAssignment::AssignedItems() const {  aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc4::IfcPresentationLayerAssignment::setAssignedItems(aggregate_of_instance::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPresentationLayerAssignment::Identifier() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcPresentationLayerAssignment::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPresentationLayerAssignment::declaration() const { return *IFC4X3_RC4_IfcPresentationLayerAssignment_type; }
@@ -19143,7 +19143,7 @@ Ifc4x3_rc4::IfcPresentationLayerWithStyle::IfcPresentationLayerWithStyle(std::st
 
 // Function implementations for IfcPresentationStyle
 boost::optional< std::string > Ifc4x3_rc4::IfcPresentationStyle::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcPresentationStyle::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPresentationStyle::declaration() const { return *IFC4X3_RC4_IfcPresentationStyle_type; }
@@ -19153,7 +19153,7 @@ Ifc4x3_rc4::IfcPresentationStyle::IfcPresentationStyle(boost::optional< std::str
 
 // Function implementations for IfcProcedure
 boost::optional< ::Ifc4x3_rc4::IfcProcedureTypeEnum::Value > Ifc4x3_rc4::IfcProcedure::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcProcedureTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc4::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProcedureTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcProcedure::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcProcedureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProcedureTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcProcedure::declaration() const { return *IFC4X3_RC4_IfcProcedure_type; }
@@ -19173,9 +19173,9 @@ Ifc4x3_rc4::IfcProcedureType::IfcProcedureType(std::string v1_GlobalId, ::Ifc4x3
 
 // Function implementations for IfcProcess
 boost::optional< std::string > Ifc4x3_rc4::IfcProcess::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcProcess::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc4::IfcRelSequence::list::ptr Ifc4x3_rc4::IfcProcess::IsPredecessorTo() const { return data_->getInverse(IFC4X3_RC4_IfcRelSequence_type, 4)->as<IfcRelSequence>(); }
 ::Ifc4x3_rc4::IfcRelSequence::list::ptr Ifc4x3_rc4::IfcProcess::IsSuccessorFrom() const { return data_->getInverse(IFC4X3_RC4_IfcRelSequence_type, 5)->as<IfcRelSequence>(); }
@@ -19213,9 +19213,9 @@ Ifc4x3_rc4::IfcProductDefinitionShape::IfcProductDefinitionShape(boost::optional
 
 // Function implementations for IfcProductRepresentation
 boost::optional< std::string > Ifc4x3_rc4::IfcProductRepresentation::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcProductRepresentation::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcProductRepresentation::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcProductRepresentation::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 aggregate_of< ::Ifc4x3_rc4::IfcRepresentation >::ptr Ifc4x3_rc4::IfcProductRepresentation::Representations() const {  aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc4::IfcRepresentation >(); }
 void Ifc4x3_rc4::IfcProductRepresentation::setRepresentations(aggregate_of< ::Ifc4x3_rc4::IfcRepresentation >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(2,attr);} }
 
@@ -19229,7 +19229,7 @@ Ifc4x3_rc4::IfcProductRepresentation::IfcProductRepresentation(boost::optional<
 ::Ifc4x3_rc4::IfcProfileTypeEnum::Value Ifc4x3_rc4::IfcProfileDef::ProfileType() const {  return ::Ifc4x3_rc4::IfcProfileTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc4::IfcProfileDef::setProfileType(::Ifc4x3_rc4::IfcProfileTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcProfileTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcProfileDef::ProfileName() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcProfileDef::setProfileName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc4::IfcExternalReferenceRelationship::list::ptr Ifc4x3_rc4::IfcProfileDef::HasExternalReference() const { return data_->getInverse(IFC4X3_RC4_IfcExternalReferenceRelationship_type, 3)->as<IfcExternalReferenceRelationship>(); }
 ::Ifc4x3_rc4::IfcProfileProperties::list::ptr Ifc4x3_rc4::IfcProfileDef::HasProperties() const { return data_->getInverse(IFC4X3_RC4_IfcProfileProperties_type, 3)->as<IfcProfileProperties>(); }
@@ -19267,11 +19267,11 @@ Ifc4x3_rc4::IfcProjectLibrary::IfcProjectLibrary(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcProjectOrder
 boost::optional< ::Ifc4x3_rc4::IfcProjectOrderTypeEnum::Value > Ifc4x3_rc4::IfcProjectOrder::PredefinedType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcProjectOrderTypeEnum::FromString(*data_->getArgument(6)); }
-void Ifc4x3_rc4::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProjectOrderTypeEnum::ToString(*v)));data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcProjectOrder::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcProjectOrderTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProjectOrderTypeEnum::ToString(*v)));}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcProjectOrder::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcProjectOrder::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcProjectOrder::LongDescription() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcProjectOrder::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcProjectOrder::declaration() const { return *IFC4X3_RC4_IfcProjectOrder_type; }
@@ -19281,9 +19281,9 @@ Ifc4x3_rc4::IfcProjectOrder::IfcProjectOrder(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcProjectedCRS
 boost::optional< std::string > Ifc4x3_rc4::IfcProjectedCRS::MapProjection() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcProjectedCRS::setMapProjection(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcProjectedCRS::MapZone() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcProjectedCRS::setMapZone(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc4::IfcNamedUnit* Ifc4x3_rc4::IfcProjectedCRS::MapUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcNamedUnit>(true); }
 void Ifc4x3_rc4::IfcProjectedCRS::setMapUnit(::Ifc4x3_rc4::IfcNamedUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -19295,7 +19295,7 @@ Ifc4x3_rc4::IfcProjectedCRS::IfcProjectedCRS(std::string v1_Name, boost::optiona
 
 // Function implementations for IfcProjectionElement
 boost::optional< ::Ifc4x3_rc4::IfcProjectionElementTypeEnum::Value > Ifc4x3_rc4::IfcProjectionElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcProjectionElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProjectionElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcProjectionElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcProjectionElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProjectionElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcProjectionElement::declaration() const { return *IFC4X3_RC4_IfcProjectionElement_type; }
@@ -19307,7 +19307,7 @@ Ifc4x3_rc4::IfcProjectionElement::IfcProjectionElement(std::string v1_GlobalId,
 std::string Ifc4x3_rc4::IfcProperty::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc4::IfcProperty::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcProperty::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcProperty::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc4::IfcPropertySet::list::ptr Ifc4x3_rc4::IfcProperty::PartOfPset() const { return data_->getInverse(IFC4X3_RC4_IfcPropertySet_type, 4)->as<IfcPropertySet>(); }
 ::Ifc4x3_rc4::IfcPropertyDependencyRelationship::list::ptr Ifc4x3_rc4::IfcProperty::PropertyForDependance() const { return data_->getInverse(IFC4X3_RC4_IfcPropertyDependencyRelationship_type, 2)->as<IfcPropertyDependencyRelationship>(); }
@@ -19362,7 +19362,7 @@ void Ifc4x3_rc4::IfcPropertyDependencyRelationship::setDependingProperty(::Ifc4x
 ::Ifc4x3_rc4::IfcProperty* Ifc4x3_rc4::IfcPropertyDependencyRelationship::DependantProperty() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcProperty>(true); }
 void Ifc4x3_rc4::IfcPropertyDependencyRelationship::setDependantProperty(::Ifc4x3_rc4::IfcProperty* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPropertyDependencyRelationship::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcPropertyDependencyRelationship::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPropertyDependencyRelationship::declaration() const { return *IFC4X3_RC4_IfcPropertyDependencyRelationship_type; }
@@ -19372,7 +19372,7 @@ Ifc4x3_rc4::IfcPropertyDependencyRelationship::IfcPropertyDependencyRelationship
 
 // Function implementations for IfcPropertyEnumeratedValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc4::IfcPropertyEnumeratedValue::EnumerationValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcPropertyEnumeratedValue::setEnumerationValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcPropertyEnumeration* Ifc4x3_rc4::IfcPropertyEnumeratedValue::EnumerationReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcPropertyEnumeration>(true); }
 void Ifc4x3_rc4::IfcPropertyEnumeratedValue::setEnumerationReference(::Ifc4x3_rc4::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19398,7 +19398,7 @@ Ifc4x3_rc4::IfcPropertyEnumeration::IfcPropertyEnumeration(std::string v1_Name,
 
 // Function implementations for IfcPropertyListValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc4::IfcPropertyListValue::ListValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcPropertyListValue::setListValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcUnit* Ifc4x3_rc4::IfcPropertyListValue::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcUnit>(true); }
 void Ifc4x3_rc4::IfcPropertyListValue::setUnit(::Ifc4x3_rc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19410,7 +19410,7 @@ Ifc4x3_rc4::IfcPropertyListValue::IfcPropertyListValue(std::string v1_Name, boos
 
 // Function implementations for IfcPropertyReferenceValue
 boost::optional< std::string > Ifc4x3_rc4::IfcPropertyReferenceValue::UsageName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcPropertyReferenceValue::setUsageName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcObjectReferenceSelect* Ifc4x3_rc4::IfcPropertyReferenceValue::PropertyReference() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcObjectReferenceSelect>(true); }
 void Ifc4x3_rc4::IfcPropertyReferenceValue::setPropertyReference(::Ifc4x3_rc4::IfcObjectReferenceSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 
@@ -19443,9 +19443,9 @@ Ifc4x3_rc4::IfcPropertySetDefinition::IfcPropertySetDefinition(std::string v1_Gl
 
 // Function implementations for IfcPropertySetTemplate
 boost::optional< ::Ifc4x3_rc4::IfcPropertySetTemplateTypeEnum::Value > Ifc4x3_rc4::IfcPropertySetTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcPropertySetTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x3_rc4::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc4::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPropertySetTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcPropertySetTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc4::IfcPropertySetTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPropertySetTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPropertySetTemplate::ApplicableEntity() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcPropertySetTemplate::setApplicableEntity(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 aggregate_of< ::Ifc4x3_rc4::IfcPropertyTemplate >::ptr Ifc4x3_rc4::IfcPropertySetTemplate::HasPropertyTemplates() const {  aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc4::IfcPropertyTemplate >(); }
 void Ifc4x3_rc4::IfcPropertySetTemplate::setHasPropertyTemplates(aggregate_of< ::Ifc4x3_rc4::IfcPropertyTemplate >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(6,attr);} }
 
@@ -19470,17 +19470,17 @@ Ifc4x3_rc4::IfcPropertySingleValue::IfcPropertySingleValue(std::string v1_Name,
 
 // Function implementations for IfcPropertyTableValue
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc4::IfcPropertyTableValue::DefiningValues() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcPropertyTableValue::setDefiningValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc4::IfcPropertyTableValue::DefinedValues() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcPropertyTableValue::setDefinedValues(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcPropertyTableValue::Expression() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcPropertyTableValue::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc4::IfcUnit* Ifc4x3_rc4::IfcPropertyTableValue::DefiningUnit() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc4::IfcUnit>(true); }
 void Ifc4x3_rc4::IfcPropertyTableValue::setDefiningUnit(::Ifc4x3_rc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 ::Ifc4x3_rc4::IfcUnit* Ifc4x3_rc4::IfcPropertyTableValue::DefinedUnit() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcUnit>(true); }
 void Ifc4x3_rc4::IfcPropertyTableValue::setDefinedUnit(::Ifc4x3_rc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcCurveInterpolationEnum::Value > Ifc4x3_rc4::IfcPropertyTableValue::CurveInterpolation() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcCurveInterpolationEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc4::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x3_rc4::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCurveInterpolationEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcPropertyTableValue::setCurveInterpolation(boost::optional< ::Ifc4x3_rc4::IfcCurveInterpolationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcCurveInterpolationEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPropertyTableValue::declaration() const { return *IFC4X3_RC4_IfcPropertyTableValue_type; }
@@ -19508,7 +19508,7 @@ Ifc4x3_rc4::IfcPropertyTemplateDefinition::IfcPropertyTemplateDefinition(std::st
 
 // Function implementations for IfcProtectiveDevice
 boost::optional< ::Ifc4x3_rc4::IfcProtectiveDeviceTypeEnum::Value > Ifc4x3_rc4::IfcProtectiveDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcProtectiveDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProtectiveDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcProtectiveDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcProtectiveDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProtectiveDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcProtectiveDevice::declaration() const { return *IFC4X3_RC4_IfcProtectiveDevice_type; }
@@ -19518,7 +19518,7 @@ Ifc4x3_rc4::IfcProtectiveDevice::IfcProtectiveDevice(std::string v1_GlobalId, ::
 
 // Function implementations for IfcProtectiveDeviceTrippingUnit
 boost::optional< ::Ifc4x3_rc4::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > Ifc4x3_rc4::IfcProtectiveDeviceTrippingUnit::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcProtectiveDeviceTrippingUnitTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcProtectiveDeviceTrippingUnit::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcProtectiveDeviceTrippingUnitTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProtectiveDeviceTrippingUnitTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcProtectiveDeviceTrippingUnit::declaration() const { return *IFC4X3_RC4_IfcProtectiveDeviceTrippingUnit_type; }
@@ -19550,7 +19550,7 @@ Ifc4x3_rc4::IfcProtectiveDeviceType::IfcProtectiveDeviceType(std::string v1_Glob
 ::Ifc4x3_rc4::IfcObjectTypeEnum::Value Ifc4x3_rc4::IfcProxy::ProxyType() const {  return ::Ifc4x3_rc4::IfcObjectTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc4::IfcProxy::setProxyType(::Ifc4x3_rc4::IfcObjectTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcObjectTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcProxy::Tag() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcProxy::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcProxy::declaration() const { return *IFC4X3_RC4_IfcProxy_type; }
@@ -19560,7 +19560,7 @@ Ifc4x3_rc4::IfcProxy::IfcProxy(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHi
 
 // Function implementations for IfcPump
 boost::optional< ::Ifc4x3_rc4::IfcPumpTypeEnum::Value > Ifc4x3_rc4::IfcPump::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcPumpTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcPump::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPumpTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcPump::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcPumpTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcPumpTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcPump::declaration() const { return *IFC4X3_RC4_IfcPump_type; }
@@ -19582,7 +19582,7 @@ Ifc4x3_rc4::IfcPumpType::IfcPumpType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 double Ifc4x3_rc4::IfcQuantityArea::AreaValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcQuantityArea::setAreaValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcQuantityArea::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcQuantityArea::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcQuantityArea::declaration() const { return *IFC4X3_RC4_IfcQuantityArea_type; }
@@ -19594,7 +19594,7 @@ Ifc4x3_rc4::IfcQuantityArea::IfcQuantityArea(std::string v1_Name, boost::optiona
 double Ifc4x3_rc4::IfcQuantityCount::CountValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcQuantityCount::setCountValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcQuantityCount::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcQuantityCount::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcQuantityCount::declaration() const { return *IFC4X3_RC4_IfcQuantityCount_type; }
@@ -19606,7 +19606,7 @@ Ifc4x3_rc4::IfcQuantityCount::IfcQuantityCount(std::string v1_Name, boost::optio
 double Ifc4x3_rc4::IfcQuantityLength::LengthValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcQuantityLength::setLengthValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcQuantityLength::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcQuantityLength::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcQuantityLength::declaration() const { return *IFC4X3_RC4_IfcQuantityLength_type; }
@@ -19626,7 +19626,7 @@ Ifc4x3_rc4::IfcQuantitySet::IfcQuantitySet(std::string v1_GlobalId, ::Ifc4x3_rc4
 double Ifc4x3_rc4::IfcQuantityTime::TimeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcQuantityTime::setTimeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcQuantityTime::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcQuantityTime::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcQuantityTime::declaration() const { return *IFC4X3_RC4_IfcQuantityTime_type; }
@@ -19638,7 +19638,7 @@ Ifc4x3_rc4::IfcQuantityTime::IfcQuantityTime(std::string v1_Name, boost::optiona
 double Ifc4x3_rc4::IfcQuantityVolume::VolumeValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcQuantityVolume::setVolumeValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcQuantityVolume::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcQuantityVolume::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcQuantityVolume::declaration() const { return *IFC4X3_RC4_IfcQuantityVolume_type; }
@@ -19650,7 +19650,7 @@ Ifc4x3_rc4::IfcQuantityVolume::IfcQuantityVolume(std::string v1_Name, boost::opt
 double Ifc4x3_rc4::IfcQuantityWeight::WeightValue() const {  double v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcQuantityWeight::setWeightValue(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcQuantityWeight::Formula() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcQuantityWeight::setFormula(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcQuantityWeight::declaration() const { return *IFC4X3_RC4_IfcQuantityWeight_type; }
@@ -19660,7 +19660,7 @@ Ifc4x3_rc4::IfcQuantityWeight::IfcQuantityWeight(std::string v1_Name, boost::opt
 
 // Function implementations for IfcRail
 boost::optional< ::Ifc4x3_rc4::IfcRailTypeEnum::Value > Ifc4x3_rc4::IfcRail::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcRailTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcRail::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRailTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRailTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcRail::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRailTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRailTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRail::declaration() const { return *IFC4X3_RC4_IfcRail_type; }
@@ -19680,7 +19680,7 @@ Ifc4x3_rc4::IfcRailType::IfcRailType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcRailing
 boost::optional< ::Ifc4x3_rc4::IfcRailingTypeEnum::Value > Ifc4x3_rc4::IfcRailing::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcRailingTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRailingTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcRailing::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRailingTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRailingTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRailing::declaration() const { return *IFC4X3_RC4_IfcRailing_type; }
@@ -19700,7 +19700,7 @@ Ifc4x3_rc4::IfcRailingType::IfcRailingType(std::string v1_GlobalId, ::Ifc4x3_rc4
 
 // Function implementations for IfcRailway
 boost::optional< ::Ifc4x3_rc4::IfcRailwayTypeEnum::Value > Ifc4x3_rc4::IfcRailway::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcRailwayTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcRailway::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRailwayTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRailwayTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcRailway::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRailwayTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRailwayTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRailway::declaration() const { return *IFC4X3_RC4_IfcRailway_type; }
@@ -19710,7 +19710,7 @@ Ifc4x3_rc4::IfcRailway::IfcRailway(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwn
 
 // Function implementations for IfcRamp
 boost::optional< ::Ifc4x3_rc4::IfcRampTypeEnum::Value > Ifc4x3_rc4::IfcRamp::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcRampTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRampTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcRamp::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRampTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRampTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRamp::declaration() const { return *IFC4X3_RC4_IfcRamp_type; }
@@ -19720,7 +19720,7 @@ Ifc4x3_rc4::IfcRamp::IfcRamp(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHist
 
 // Function implementations for IfcRampFlight
 boost::optional< ::Ifc4x3_rc4::IfcRampFlightTypeEnum::Value > Ifc4x3_rc4::IfcRampFlight::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcRampFlightTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRampFlightTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcRampFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRampFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRampFlightTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRampFlight::declaration() const { return *IFC4X3_RC4_IfcRampFlight_type; }
@@ -19772,9 +19772,9 @@ Ifc4x3_rc4::IfcRationalBSplineSurfaceWithKnots::IfcRationalBSplineSurfaceWithKno
 double Ifc4x3_rc4::IfcRectangleHollowProfileDef::WallThickness() const {  double v = *data_->getArgument(5); return v; }
 void Ifc4x3_rc4::IfcRectangleHollowProfileDef::setWallThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcRectangleHollowProfileDef::InnerFilletRadius() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcRectangleHollowProfileDef::setInnerFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcRectangleHollowProfileDef::OuterFilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcRectangleHollowProfileDef::setOuterFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRectangleHollowProfileDef::declaration() const { return *IFC4X3_RC4_IfcRectangleHollowProfileDef_type; }
@@ -19834,19 +19834,19 @@ Ifc4x3_rc4::IfcRectangularTrimmedSurface::IfcRectangularTrimmedSurface(::Ifc4x3_
 ::Ifc4x3_rc4::IfcRecurrenceTypeEnum::Value Ifc4x3_rc4::IfcRecurrencePattern::RecurrenceType() const {  return ::Ifc4x3_rc4::IfcRecurrenceTypeEnum::FromString(*data_->getArgument(0)); }
 void Ifc4x3_rc4::IfcRecurrencePattern::setRecurrenceType(::Ifc4x3_rc4::IfcRecurrenceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcRecurrenceTypeEnum::ToString(v)));data_->setArgument(0,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc4::IfcRecurrencePattern::DayComponent() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcRecurrencePattern::setDayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc4::IfcRecurrencePattern::WeekdayComponent() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcRecurrencePattern::setWeekdayComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc4::IfcRecurrencePattern::MonthComponent() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcRecurrencePattern::setMonthComponent(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< int > Ifc4x3_rc4::IfcRecurrencePattern::Position() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } int v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcRecurrencePattern::setPosition(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< int > Ifc4x3_rc4::IfcRecurrencePattern::Interval() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } int v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcRecurrencePattern::setInterval(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< int > Ifc4x3_rc4::IfcRecurrencePattern::Occurrences() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } int v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcRecurrencePattern::setOccurrences(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcTimePeriod >::ptr > Ifc4x3_rc4::IfcRecurrencePattern::TimePeriods() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc4::IfcTimePeriod >(); }
-void Ifc4x3_rc4::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcRecurrencePattern::setTimePeriods(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcTimePeriod >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRecurrencePattern::declaration() const { return *IFC4X3_RC4_IfcRecurrencePattern_type; }
@@ -19856,13 +19856,13 @@ Ifc4x3_rc4::IfcRecurrencePattern::IfcRecurrencePattern(::Ifc4x3_rc4::IfcRecurren
 
 // Function implementations for IfcReference
 boost::optional< std::string > Ifc4x3_rc4::IfcReference::TypeIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcReference::setTypeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcReference::AttributeIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcReference::setAttributeIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcReference::InstanceName() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcReference::setInstanceName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc4::IfcReference::ListPositions() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcReference::setListPositions(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 ::Ifc4x3_rc4::IfcReference* Ifc4x3_rc4::IfcReference::InnerReference() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc4::IfcReference>(true); }
 void Ifc4x3_rc4::IfcReference::setInnerReference(::Ifc4x3_rc4::IfcReference* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 
@@ -19874,9 +19874,9 @@ Ifc4x3_rc4::IfcReference::IfcReference(boost::optional< std::string > v1_TypeIde
 
 // Function implementations for IfcReferent
 boost::optional< ::Ifc4x3_rc4::IfcReferentTypeEnum::Value > Ifc4x3_rc4::IfcReferent::PredefinedType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcReferentTypeEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc4::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReferentTypeEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcReferent::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcReferentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReferentTypeEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReferent::RestartDistance() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcReferent::setRestartDistance(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcReferent::declaration() const { return *IFC4X3_RC4_IfcReferent_type; }
@@ -19898,7 +19898,7 @@ Ifc4x3_rc4::IfcRegularTimeSeries::IfcRegularTimeSeries(std::string v1_Name, boos
 
 // Function implementations for IfcReinforcedSoil
 boost::optional< ::Ifc4x3_rc4::IfcReinforcedSoilTypeEnum::Value > Ifc4x3_rc4::IfcReinforcedSoil::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcReinforcedSoilTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcReinforcedSoil::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcReinforcedSoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcedSoilTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcReinforcedSoil::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcReinforcedSoilTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcedSoilTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcReinforcedSoil::declaration() const { return *IFC4X3_RC4_IfcReinforcedSoil_type; }
@@ -19912,13 +19912,13 @@ void Ifc4x3_rc4::IfcReinforcementBarProperties::setTotalCrossSectionArea(double
 std::string Ifc4x3_rc4::IfcReinforcementBarProperties::SteelGrade() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcReinforcementBarProperties::setSteelGrade(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc4::IfcReinforcementBarProperties::BarSurface() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc4::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcReinforcementBarProperties::setBarSurface(boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcementBarProperties::EffectiveDepth() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcReinforcementBarProperties::setEffectiveDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcementBarProperties::NominalBarDiameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcReinforcementBarProperties::setNominalBarDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcementBarProperties::BarCount() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcReinforcementBarProperties::setBarCount(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcReinforcementBarProperties::declaration() const { return *IFC4X3_RC4_IfcReinforcementBarProperties_type; }
@@ -19928,7 +19928,7 @@ Ifc4x3_rc4::IfcReinforcementBarProperties::IfcReinforcementBarProperties(double
 
 // Function implementations for IfcReinforcementDefinitionProperties
 boost::optional< std::string > Ifc4x3_rc4::IfcReinforcementDefinitionProperties::DefinitionType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcReinforcementDefinitionProperties::setDefinitionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 aggregate_of< ::Ifc4x3_rc4::IfcSectionReinforcementProperties >::ptr Ifc4x3_rc4::IfcReinforcementDefinitionProperties::ReinforcementSectionDefinitions() const {  aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc4::IfcSectionReinforcementProperties >(); }
 void Ifc4x3_rc4::IfcReinforcementDefinitionProperties::setReinforcementSectionDefinitions(aggregate_of< ::Ifc4x3_rc4::IfcSectionReinforcementProperties >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(5,attr);} }
 
@@ -19940,15 +19940,15 @@ Ifc4x3_rc4::IfcReinforcementDefinitionProperties::IfcReinforcementDefinitionProp
 
 // Function implementations for IfcReinforcingBar
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingBar::NominalDiameter() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBar::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingBar::CrossSectionArea() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBar::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingBar::BarLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBar::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarTypeEnum::Value > Ifc4x3_rc4::IfcReinforcingBar::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc4::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcingBarTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBar::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcingBarTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc4::IfcReinforcingBar::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc4::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBar::setBarSurface(boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcReinforcingBar::declaration() const { return *IFC4X3_RC4_IfcReinforcingBar_type; }
@@ -19960,17 +19960,17 @@ Ifc4x3_rc4::IfcReinforcingBar::IfcReinforcingBar(std::string v1_GlobalId, ::Ifc4
 ::Ifc4x3_rc4::IfcReinforcingBarTypeEnum::Value Ifc4x3_rc4::IfcReinforcingBarType::PredefinedType() const {  return ::Ifc4x3_rc4::IfcReinforcingBarTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc4::IfcReinforcingBarType::setPredefinedType(::Ifc4x3_rc4::IfcReinforcingBarTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcReinforcingBarTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingBarType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBarType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingBarType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBarType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingBarType::BarLength() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBarType::setBarLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::Value > Ifc4x3_rc4::IfcReinforcingBarType::BarSurface() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc4::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBarType::setBarSurface(boost::optional< ::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcingBarSurfaceEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcReinforcingBarType::BendingShapeCode() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc4::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBarType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc4::IfcReinforcingBarType::BendingParameters() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc4::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc4::IfcReinforcingBarType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcReinforcingBarType::declaration() const { return *IFC4X3_RC4_IfcReinforcingBarType_type; }
@@ -19980,7 +19980,7 @@ Ifc4x3_rc4::IfcReinforcingBarType::IfcReinforcingBarType(std::string v1_GlobalId
 
 // Function implementations for IfcReinforcingElement
 boost::optional< std::string > Ifc4x3_rc4::IfcReinforcingElement::SteelGrade() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcReinforcingElement::setSteelGrade(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcReinforcingElement::declaration() const { return *IFC4X3_RC4_IfcReinforcingElement_type; }
@@ -19998,23 +19998,23 @@ Ifc4x3_rc4::IfcReinforcingElementType::IfcReinforcingElementType(std::string v1_
 
 // Function implementations for IfcReinforcingMesh
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMesh::MeshLength() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMesh::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMesh::MeshWidth() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMesh::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMesh::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMesh::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMesh::TransverseBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMesh::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMesh::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc4::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMesh::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMesh::TransverseBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc4::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMesh::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMesh::LongitudinalBarSpacing() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc4::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMesh::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMesh::TransverseBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc4::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMesh::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcReinforcingMeshTypeEnum::Value > Ifc4x3_rc4::IfcReinforcingMesh::PredefinedType() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(17)); }
-void Ifc4x3_rc4::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcingMeshTypeEnum::ToString(*v)));data_->setArgument(17,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMesh::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcReinforcingMeshTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcReinforcingMeshTypeEnum::ToString(*v)));}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcReinforcingMesh::declaration() const { return *IFC4X3_RC4_IfcReinforcingMesh_type; }
@@ -20026,25 +20026,25 @@ Ifc4x3_rc4::IfcReinforcingMesh::IfcReinforcingMesh(std::string v1_GlobalId, ::If
 ::Ifc4x3_rc4::IfcReinforcingMeshTypeEnum::Value Ifc4x3_rc4::IfcReinforcingMeshType::PredefinedType() const {  return ::Ifc4x3_rc4::IfcReinforcingMeshTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc4::IfcReinforcingMeshType::setPredefinedType(::Ifc4x3_rc4::IfcReinforcingMeshTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcReinforcingMeshTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMeshType::MeshLength() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMeshType::setMeshLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMeshType::MeshWidth() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMeshType::setMeshWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMeshType::LongitudinalBarNominalDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMeshType::setLongitudinalBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMeshType::TransverseBarNominalDiameter() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc4::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMeshType::setTransverseBarNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMeshType::LongitudinalBarCrossSectionArea() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc4::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMeshType::setLongitudinalBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMeshType::TransverseBarCrossSectionArea() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc4::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMeshType::setTransverseBarCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMeshType::LongitudinalBarSpacing() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc4::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMeshType::setLongitudinalBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcReinforcingMeshType::TransverseBarSpacing() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc4::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMeshType::setTransverseBarSpacing(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcReinforcingMeshType::BendingShapeCode() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x3_rc4::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMeshType::setBendingShapeCode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc4::IfcReinforcingMeshType::BendingParameters() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(19); return v; }
-void Ifc4x3_rc4::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x3_rc4::IfcReinforcingMeshType::setBendingParameters(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcReinforcingMeshType::declaration() const { return *IFC4X3_RC4_IfcReinforcingMeshType_type; }
@@ -20080,7 +20080,7 @@ Ifc4x3_rc4::IfcRelAggregates::IfcRelAggregates(std::string v1_GlobalId, ::Ifc4x3
 aggregate_of< ::Ifc4x3_rc4::IfcObjectDefinition >::ptr Ifc4x3_rc4::IfcRelAssigns::RelatedObjects() const {  aggregate_of_instance::ptr es = *data_->getArgument(4); return es->as< ::Ifc4x3_rc4::IfcObjectDefinition >(); }
 void Ifc4x3_rc4::IfcRelAssigns::setRelatedObjects(aggregate_of< ::Ifc4x3_rc4::IfcObjectDefinition >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(4,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcObjectTypeEnum::Value > Ifc4x3_rc4::IfcRelAssigns::RelatedObjectsType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcObjectTypeEnum::FromString(*data_->getArgument(5)); }
-void Ifc4x3_rc4::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x3_rc4::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcObjectTypeEnum::ToString(*v)));data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcRelAssigns::setRelatedObjectsType(boost::optional< ::Ifc4x3_rc4::IfcObjectTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcObjectTypeEnum::ToString(*v)));}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRelAssigns::declaration() const { return *IFC4X3_RC4_IfcRelAssigns_type; }
@@ -20194,7 +20194,7 @@ Ifc4x3_rc4::IfcRelAssociatesClassification::IfcRelAssociatesClassification(std::
 
 // Function implementations for IfcRelAssociatesConstraint
 boost::optional< std::string > Ifc4x3_rc4::IfcRelAssociatesConstraint::Intent() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcRelAssociatesConstraint::setIntent(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc4::IfcConstraint* Ifc4x3_rc4::IfcRelAssociatesConstraint::RelatingConstraint() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcConstraint>(true); }
 void Ifc4x3_rc4::IfcRelAssociatesConstraint::setRelatingConstraint(::Ifc4x3_rc4::IfcConstraint* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -20330,7 +20330,7 @@ void Ifc4x3_rc4::IfcRelConnectsStructuralMember::setAppliedCondition(::Ifc4x3_rc
 ::Ifc4x3_rc4::IfcStructuralConnectionCondition* Ifc4x3_rc4::IfcRelConnectsStructuralMember::AdditionalConditions() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc4::IfcStructuralConnectionCondition>(true); }
 void Ifc4x3_rc4::IfcRelConnectsStructuralMember::setAdditionalConditions(::Ifc4x3_rc4::IfcStructuralConnectionCondition* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcRelConnectsStructuralMember::SupportedLength() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcRelConnectsStructuralMember::setSupportedLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc4::IfcAxis2Placement3D* Ifc4x3_rc4::IfcRelConnectsStructuralMember::ConditionCoordinateSystem() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc4::IfcAxis2Placement3D>(true); }
 void Ifc4x3_rc4::IfcRelConnectsStructuralMember::setConditionCoordinateSystem(::Ifc4x3_rc4::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -20354,7 +20354,7 @@ Ifc4x3_rc4::IfcRelConnectsWithEccentricity::IfcRelConnectsWithEccentricity(std::
 aggregate_of< ::Ifc4x3_rc4::IfcElement >::ptr Ifc4x3_rc4::IfcRelConnectsWithRealizingElements::RealizingElements() const {  aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc4::IfcElement >(); }
 void Ifc4x3_rc4::IfcRelConnectsWithRealizingElements::setRealizingElements(aggregate_of< ::Ifc4x3_rc4::IfcElement >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcRelConnectsWithRealizingElements::ConnectionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcRelConnectsWithRealizingElements::setConnectionType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRelConnectsWithRealizingElements::declaration() const { return *IFC4X3_RC4_IfcRelConnectsWithRealizingElements_type; }
@@ -20508,7 +20508,7 @@ void Ifc4x3_rc4::IfcRelInterferesElements::setInterferenceGeometry(::Ifc4x3_rc4:
 ::Ifc4x3_rc4::IfcSpatialZone* Ifc4x3_rc4::IfcRelInterferesElements::InterferenceSpace() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc4::IfcSpatialZone>(true); }
 void Ifc4x3_rc4::IfcRelInterferesElements::setInterferenceSpace(::Ifc4x3_rc4::IfcSpatialZone* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcRelInterferesElements::InterferenceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcRelInterferesElements::setInterferenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::logic::tribool Ifc4x3_rc4::IfcRelInterferesElements::ImpliedOrder() const {  boost::logic::tribool v = *data_->getArgument(9); return v; }
 void Ifc4x3_rc4::IfcRelInterferesElements::setImpliedOrder(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -20574,9 +20574,9 @@ void Ifc4x3_rc4::IfcRelSequence::setRelatedProcess(::Ifc4x3_rc4::IfcProcess* v)
 ::Ifc4x3_rc4::IfcLagTime* Ifc4x3_rc4::IfcRelSequence::TimeLag() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcLagTime>(true); }
 void Ifc4x3_rc4::IfcRelSequence::setTimeLag(::Ifc4x3_rc4::IfcLagTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcSequenceEnum::Value > Ifc4x3_rc4::IfcRelSequence::SequenceType() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSequenceEnum::FromString(*data_->getArgument(7)); }
-void Ifc4x3_rc4::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x3_rc4::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSequenceEnum::ToString(*v)));data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcRelSequence::setSequenceType(boost::optional< ::Ifc4x3_rc4::IfcSequenceEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSequenceEnum::ToString(*v)));}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcRelSequence::UserDefinedSequenceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcRelSequence::setUserDefinedSequenceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRelSequence::declaration() const { return *IFC4X3_RC4_IfcRelSequence_type; }
@@ -20670,9 +20670,9 @@ Ifc4x3_rc4::IfcReparametrisedCompositeCurveSegment::IfcReparametrisedCompositeCu
 ::Ifc4x3_rc4::IfcRepresentationContext* Ifc4x3_rc4::IfcRepresentation::ContextOfItems() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc4::IfcRepresentationContext>(true); }
 void Ifc4x3_rc4::IfcRepresentation::setContextOfItems(::Ifc4x3_rc4::IfcRepresentationContext* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcRepresentation::RepresentationIdentifier() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcRepresentation::setRepresentationIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcRepresentation::RepresentationType() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcRepresentation::setRepresentationType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 aggregate_of< ::Ifc4x3_rc4::IfcRepresentationItem >::ptr Ifc4x3_rc4::IfcRepresentation::Items() const {  aggregate_of_instance::ptr es = *data_->getArgument(3); return es->as< ::Ifc4x3_rc4::IfcRepresentationItem >(); }
 void Ifc4x3_rc4::IfcRepresentation::setItems(aggregate_of< ::Ifc4x3_rc4::IfcRepresentationItem >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(3,attr);} }
 
@@ -20687,9 +20687,9 @@ Ifc4x3_rc4::IfcRepresentation::IfcRepresentation(::Ifc4x3_rc4::IfcRepresentation
 
 // Function implementations for IfcRepresentationContext
 boost::optional< std::string > Ifc4x3_rc4::IfcRepresentationContext::ContextIdentifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcRepresentationContext::setContextIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcRepresentationContext::ContextType() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcRepresentationContext::setContextType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 ::Ifc4x3_rc4::IfcRepresentation::list::ptr Ifc4x3_rc4::IfcRepresentationContext::RepresentationsInContext() const { return data_->getInverse(IFC4X3_RC4_IfcRepresentation_type, 0)->as<IfcRepresentation>(); }
 
@@ -20724,9 +20724,9 @@ Ifc4x3_rc4::IfcRepresentationMap::IfcRepresentationMap(::Ifc4x3_rc4::IfcAxis2Pla
 
 // Function implementations for IfcResource
 boost::optional< std::string > Ifc4x3_rc4::IfcResource::Identification() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResource::LongDescription() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 ::Ifc4x3_rc4::IfcRelAssignsToResource::list::ptr Ifc4x3_rc4::IfcResource::ResourceOf() const { return data_->getInverse(IFC4X3_RC4_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -20761,9 +20761,9 @@ Ifc4x3_rc4::IfcResourceConstraintRelationship::IfcResourceConstraintRelationship
 
 // Function implementations for IfcResourceLevelRelationship
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceLevelRelationship::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcResourceLevelRelationship::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceLevelRelationship::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcResourceLevelRelationship::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcResourceLevelRelationship::declaration() const { return *IFC4X3_RC4_IfcResourceLevelRelationship_type; }
@@ -20773,35 +20773,35 @@ Ifc4x3_rc4::IfcResourceLevelRelationship::IfcResourceLevelRelationship(boost::op
 
 // Function implementations for IfcResourceTime
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceTime::ScheduleWork() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setScheduleWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcResourceTime::ScheduleUsage() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setScheduleUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceTime::ScheduleContour() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setScheduleContour(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceTime::LevelingDelay() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setLevelingDelay(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< bool > Ifc4x3_rc4::IfcResourceTime::IsOverAllocated() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setIsOverAllocated(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceTime::StatusTime() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceTime::ActualWork() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setActualWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcResourceTime::ActualUsage() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setActualUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceTime::ActualStart() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } std::string v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceTime::ActualFinish() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcResourceTime::RemainingWork() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setRemainingWork(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcResourceTime::RemainingUsage() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setRemainingUsage(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcResourceTime::Completion() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } double v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc4::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc4::IfcResourceTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcResourceTime::declaration() const { return *IFC4X3_RC4_IfcResourceTime_type; }
@@ -20857,7 +20857,7 @@ Ifc4x3_rc4::IfcRightCircularCylinder::IfcRightCircularCylinder(::Ifc4x3_rc4::Ifc
 
 // Function implementations for IfcRoad
 boost::optional< ::Ifc4x3_rc4::IfcRoadTypeEnum::Value > Ifc4x3_rc4::IfcRoad::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcRoadTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcRoad::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRoadTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRoadTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcRoad::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRoadTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRoadTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRoad::declaration() const { return *IFC4X3_RC4_IfcRoad_type; }
@@ -20867,7 +20867,7 @@ Ifc4x3_rc4::IfcRoad::IfcRoad(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHist
 
 // Function implementations for IfcRoof
 boost::optional< ::Ifc4x3_rc4::IfcRoofTypeEnum::Value > Ifc4x3_rc4::IfcRoof::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcRoofTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRoofTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcRoof::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcRoofTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcRoofTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRoof::declaration() const { return *IFC4X3_RC4_IfcRoof_type; }
@@ -20891,9 +20891,9 @@ void Ifc4x3_rc4::IfcRoot::setGlobalId(std::string v) { {IfcWrite::IfcWriteArgume
 ::Ifc4x3_rc4::IfcOwnerHistory* Ifc4x3_rc4::IfcRoot::OwnerHistory() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(1)))->as<::Ifc4x3_rc4::IfcOwnerHistory>(true); }
 void Ifc4x3_rc4::IfcRoot::setOwnerHistory(::Ifc4x3_rc4::IfcOwnerHistory* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcRoot::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcRoot::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcRoot::Description() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcRoot::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcRoot::declaration() const { return *IFC4X3_RC4_IfcRoot_type; }
@@ -20913,7 +20913,7 @@ Ifc4x3_rc4::IfcRoundedRectangleProfileDef::IfcRoundedRectangleProfileDef(::Ifc4x
 
 // Function implementations for IfcSIUnit
 boost::optional< ::Ifc4x3_rc4::IfcSIPrefix::Value > Ifc4x3_rc4::IfcSIUnit::Prefix() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSIPrefix::FromString(*data_->getArgument(2)); }
-void Ifc4x3_rc4::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x3_rc4::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSIPrefix::ToString(*v)));data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcSIUnit::setPrefix(boost::optional< ::Ifc4x3_rc4::IfcSIPrefix::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSIPrefix::ToString(*v)));}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcSIUnitName::Value Ifc4x3_rc4::IfcSIUnit::Name() const {  return ::Ifc4x3_rc4::IfcSIUnitName::FromString(*data_->getArgument(3)); }
 void Ifc4x3_rc4::IfcSIUnit::setName(::Ifc4x3_rc4::IfcSIUnitName::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcSIUnitName::ToString(v)));data_->setArgument(3,attr);} }
 
@@ -20925,7 +20925,7 @@ Ifc4x3_rc4::IfcSIUnit::IfcSIUnit(::Ifc4x3_rc4::IfcUnitEnum::Value v2_UnitType, b
 
 // Function implementations for IfcSanitaryTerminal
 boost::optional< ::Ifc4x3_rc4::IfcSanitaryTerminalTypeEnum::Value > Ifc4x3_rc4::IfcSanitaryTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSanitaryTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSanitaryTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSanitaryTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSanitaryTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSanitaryTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSanitaryTerminal::declaration() const { return *IFC4X3_RC4_IfcSanitaryTerminal_type; }
@@ -20945,11 +20945,11 @@ Ifc4x3_rc4::IfcSanitaryTerminalType::IfcSanitaryTerminalType(std::string v1_Glob
 
 // Function implementations for IfcSchedulingTime
 boost::optional< std::string > Ifc4x3_rc4::IfcSchedulingTime::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcSchedulingTime::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcDataOriginEnum::Value > Ifc4x3_rc4::IfcSchedulingTime::DataOrigin() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcDataOriginEnum::FromString(*data_->getArgument(1)); }
-void Ifc4x3_rc4::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x3_rc4::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDataOriginEnum::ToString(*v)));data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcSchedulingTime::setDataOrigin(boost::optional< ::Ifc4x3_rc4::IfcDataOriginEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcDataOriginEnum::ToString(*v)));}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcSchedulingTime::UserDefinedDataOrigin() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcSchedulingTime::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSchedulingTime::declaration() const { return *IFC4X3_RC4_IfcSchedulingTime_type; }
@@ -20969,9 +20969,9 @@ Ifc4x3_rc4::IfcSeamCurve::IfcSeamCurve(::Ifc4x3_rc4::IfcCurve* v1_Curve3D, aggre
 double Ifc4x3_rc4::IfcSecondOrderPolynomialSpiral::QuadraticTerm() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcSecondOrderPolynomialSpiral::setQuadraticTerm(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSecondOrderPolynomialSpiral::LinearTerm() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcSecondOrderPolynomialSpiral::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcSecondOrderPolynomialSpiral::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSecondOrderPolynomialSpiral::ConstantTerm() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcSecondOrderPolynomialSpiral::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcSecondOrderPolynomialSpiral::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSecondOrderPolynomialSpiral::declaration() const { return *IFC4X3_RC4_IfcSecondOrderPolynomialSpiral_type; }
@@ -20999,7 +20999,7 @@ void Ifc4x3_rc4::IfcSectionReinforcementProperties::setLongitudinalStartPosition
 double Ifc4x3_rc4::IfcSectionReinforcementProperties::LongitudinalEndPosition() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcSectionReinforcementProperties::setLongitudinalEndPosition(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSectionReinforcementProperties::TransversePosition() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcSectionReinforcementProperties::setTransversePosition(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcReinforcingBarRoleEnum::Value Ifc4x3_rc4::IfcSectionReinforcementProperties::ReinforcementRole() const {  return ::Ifc4x3_rc4::IfcReinforcingBarRoleEnum::FromString(*data_->getArgument(3)); }
 void Ifc4x3_rc4::IfcSectionReinforcementProperties::setReinforcementRole(::Ifc4x3_rc4::IfcReinforcingBarRoleEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcReinforcingBarRoleEnum::ToString(v)));data_->setArgument(3,attr);} }
 ::Ifc4x3_rc4::IfcSectionProperties* Ifc4x3_rc4::IfcSectionReinforcementProperties::SectionDefinition() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc4::IfcSectionProperties>(true); }
@@ -21092,7 +21092,7 @@ Ifc4x3_rc4::IfcSegmentedReferenceCurve::IfcSegmentedReferenceCurve(aggregate_of<
 
 // Function implementations for IfcSensor
 boost::optional< ::Ifc4x3_rc4::IfcSensorTypeEnum::Value > Ifc4x3_rc4::IfcSensor::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSensorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSensorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSensor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSensorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSensorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSensor::declaration() const { return *IFC4X3_RC4_IfcSensor_type; }
@@ -21114,19 +21114,19 @@ Ifc4x3_rc4::IfcSensorType::IfcSensorType(std::string v1_GlobalId, ::Ifc4x3_rc4::
 double Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::SepticTerm() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setSepticTerm(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::SexticTerm() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setSexticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setSexticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::QuinticTerm() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setQuinticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setQuinticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::QuarticTerm() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setQuarticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setQuarticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::CubicTerm() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setCubicTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setCubicTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::QuadraticTerm() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setQuadraticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setQuadraticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::LinearTerm() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::ConstantTerm() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::declaration() const { return *IFC4X3_RC4_IfcSeventhOrderPolynomialSpiral_type; }
@@ -21136,7 +21136,7 @@ Ifc4x3_rc4::IfcSeventhOrderPolynomialSpiral::IfcSeventhOrderPolynomialSpiral(::I
 
 // Function implementations for IfcShadingDevice
 boost::optional< ::Ifc4x3_rc4::IfcShadingDeviceTypeEnum::Value > Ifc4x3_rc4::IfcShadingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcShadingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcShadingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcShadingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcShadingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcShadingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcShadingDevice::declaration() const { return *IFC4X3_RC4_IfcShadingDevice_type; }
@@ -21158,9 +21158,9 @@ Ifc4x3_rc4::IfcShadingDeviceType::IfcShadingDeviceType(std::string v1_GlobalId,
 aggregate_of< ::Ifc4x3_rc4::IfcShapeModel >::ptr Ifc4x3_rc4::IfcShapeAspect::ShapeRepresentations() const {  aggregate_of_instance::ptr es = *data_->getArgument(0); return es->as< ::Ifc4x3_rc4::IfcShapeModel >(); }
 void Ifc4x3_rc4::IfcShapeAspect::setShapeRepresentations(aggregate_of< ::Ifc4x3_rc4::IfcShapeModel >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcShapeAspect::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcShapeAspect::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcShapeAspect::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcShapeAspect::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::logic::tribool Ifc4x3_rc4::IfcShapeAspect::ProductDefinitional() const {  boost::logic::tribool v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcShapeAspect::setProductDefinitional(boost::logic::tribool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc4::IfcProductRepresentationSelect* Ifc4x3_rc4::IfcShapeAspect::PartOfProductDefinitionShape() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc4::IfcProductRepresentationSelect>(true); }
@@ -21202,7 +21202,7 @@ Ifc4x3_rc4::IfcShellBasedSurfaceModel::IfcShellBasedSurfaceModel(aggregate_of_in
 
 // Function implementations for IfcSign
 boost::optional< ::Ifc4x3_rc4::IfcSignTypeEnum::Value > Ifc4x3_rc4::IfcSign::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSignTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSign::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSignTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSignTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSign::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSignTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSignTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSign::declaration() const { return *IFC4X3_RC4_IfcSign_type; }
@@ -21222,7 +21222,7 @@ Ifc4x3_rc4::IfcSignType::IfcSignType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcSignal
 boost::optional< ::Ifc4x3_rc4::IfcSignalTypeEnum::Value > Ifc4x3_rc4::IfcSignal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSignalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSignal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSignalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSignalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSignal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSignalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSignalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSignal::declaration() const { return *IFC4X3_RC4_IfcSignal_type; }
@@ -21250,11 +21250,11 @@ Ifc4x3_rc4::IfcSimpleProperty::IfcSimpleProperty(std::string v1_Name, boost::opt
 
 // Function implementations for IfcSimplePropertyTemplate
 boost::optional< ::Ifc4x3_rc4::IfcSimplePropertyTemplateTypeEnum::Value > Ifc4x3_rc4::IfcSimplePropertyTemplate::TemplateType() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSimplePropertyTemplateTypeEnum::FromString(*data_->getArgument(4)); }
-void Ifc4x3_rc4::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc4::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcSimplePropertyTemplate::setTemplateType(boost::optional< ::Ifc4x3_rc4::IfcSimplePropertyTemplateTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSimplePropertyTemplateTypeEnum::ToString(*v)));}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcSimplePropertyTemplate::PrimaryMeasureType() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcSimplePropertyTemplate::setPrimaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcSimplePropertyTemplate::SecondaryMeasureType() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcSimplePropertyTemplate::setSecondaryMeasureType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc4::IfcPropertyEnumeration* Ifc4x3_rc4::IfcSimplePropertyTemplate::Enumerators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc4::IfcPropertyEnumeration>(true); }
 void Ifc4x3_rc4::IfcSimplePropertyTemplate::setEnumerators(::Ifc4x3_rc4::IfcPropertyEnumeration* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcUnit* Ifc4x3_rc4::IfcSimplePropertyTemplate::PrimaryUnit() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc4::IfcUnit>(true); }
@@ -21262,9 +21262,9 @@ void Ifc4x3_rc4::IfcSimplePropertyTemplate::setPrimaryUnit(::Ifc4x3_rc4::IfcUnit
 ::Ifc4x3_rc4::IfcUnit* Ifc4x3_rc4::IfcSimplePropertyTemplate::SecondaryUnit() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc4::IfcUnit>(true); }
 void Ifc4x3_rc4::IfcSimplePropertyTemplate::setSecondaryUnit(::Ifc4x3_rc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcSimplePropertyTemplate::Expression() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcSimplePropertyTemplate::setExpression(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcStateEnum::Value > Ifc4x3_rc4::IfcSimplePropertyTemplate::AccessState() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcStateEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc4::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x3_rc4::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcStateEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcSimplePropertyTemplate::setAccessState(boost::optional< ::Ifc4x3_rc4::IfcStateEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcStateEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSimplePropertyTemplate::declaration() const { return *IFC4X3_RC4_IfcSimplePropertyTemplate_type; }
@@ -21276,9 +21276,9 @@ Ifc4x3_rc4::IfcSimplePropertyTemplate::IfcSimplePropertyTemplate(std::string v1_
 double Ifc4x3_rc4::IfcSine::SineTerm() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcSine::setSineTerm(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSine::LinearTerm() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcSine::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcSine::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSine::ConstantTerm() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcSine::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcSine::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSine::declaration() const { return *IFC4X3_RC4_IfcSine_type; }
@@ -21288,13 +21288,13 @@ Ifc4x3_rc4::IfcSine::IfcSine(::Ifc4x3_rc4::IfcAxis2Placement* v1_Position, doubl
 
 // Function implementations for IfcSite
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x3_rc4::IfcSite::RefLatitude() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcSite::setRefLatitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::vector< int > /*[3:4]*/ > Ifc4x3_rc4::IfcSite::RefLongitude() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< int > /*[3:4]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcSite::setRefLongitude(boost::optional< std::vector< int > /*[3:4]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSite::RefElevation() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcSite::setRefElevation(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcSite::LandTitleNumber() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcSite::setLandTitleNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 ::Ifc4x3_rc4::IfcPostalAddress* Ifc4x3_rc4::IfcSite::SiteAddress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(13)))->as<::Ifc4x3_rc4::IfcPostalAddress>(true); }
 void Ifc4x3_rc4::IfcSite::setSiteAddress(::Ifc4x3_rc4::IfcPostalAddress* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(13,attr);} }
 
@@ -21306,7 +21306,7 @@ Ifc4x3_rc4::IfcSite::IfcSite(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHist
 
 // Function implementations for IfcSlab
 boost::optional< ::Ifc4x3_rc4::IfcSlabTypeEnum::Value > Ifc4x3_rc4::IfcSlab::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSlabTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSlabTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSlab::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSlabTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSlabTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSlab::declaration() const { return *IFC4X3_RC4_IfcSlab_type; }
@@ -21342,11 +21342,11 @@ Ifc4x3_rc4::IfcSlabType::IfcSlabType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcSlippageConnectionCondition
 boost::optional< double > Ifc4x3_rc4::IfcSlippageConnectionCondition::SlippageX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcSlippageConnectionCondition::setSlippageX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSlippageConnectionCondition::SlippageY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcSlippageConnectionCondition::setSlippageY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSlippageConnectionCondition::SlippageZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcSlippageConnectionCondition::setSlippageZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSlippageConnectionCondition::declaration() const { return *IFC4X3_RC4_IfcSlippageConnectionCondition_type; }
@@ -21356,7 +21356,7 @@ Ifc4x3_rc4::IfcSlippageConnectionCondition::IfcSlippageConnectionCondition(boost
 
 // Function implementations for IfcSolarDevice
 boost::optional< ::Ifc4x3_rc4::IfcSolarDeviceTypeEnum::Value > Ifc4x3_rc4::IfcSolarDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSolarDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSolarDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSolarDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSolarDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSolarDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSolarDevice::declaration() const { return *IFC4X3_RC4_IfcSolarDevice_type; }
@@ -21392,9 +21392,9 @@ Ifc4x3_rc4::IfcSolidStratum::IfcSolidStratum(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcSpace
 boost::optional< ::Ifc4x3_rc4::IfcSpaceTypeEnum::Value > Ifc4x3_rc4::IfcSpace::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSpaceTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcSpace::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSpaceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSpaceTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSpace::ElevationWithFlooring() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcSpace::setElevationWithFlooring(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 ::Ifc4x3_rc4::IfcRelCoversSpaces::list::ptr Ifc4x3_rc4::IfcSpace::HasCoverings() const { return data_->getInverse(IFC4X3_RC4_IfcRelCoversSpaces_type, 4)->as<IfcRelCoversSpaces>(); }
 ::Ifc4x3_rc4::IfcRelSpaceBoundary::list::ptr Ifc4x3_rc4::IfcSpace::BoundedBy() const { return data_->getInverse(IFC4X3_RC4_IfcRelSpaceBoundary_type, 4)->as<IfcRelSpaceBoundary>(); }
@@ -21406,7 +21406,7 @@ Ifc4x3_rc4::IfcSpace::IfcSpace(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHi
 
 // Function implementations for IfcSpaceHeater
 boost::optional< ::Ifc4x3_rc4::IfcSpaceHeaterTypeEnum::Value > Ifc4x3_rc4::IfcSpaceHeater::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSpaceHeaterTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSpaceHeaterTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSpaceHeater::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSpaceHeaterTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSpaceHeaterTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSpaceHeater::declaration() const { return *IFC4X3_RC4_IfcSpaceHeater_type; }
@@ -21428,7 +21428,7 @@ Ifc4x3_rc4::IfcSpaceHeaterType::IfcSpaceHeaterType(std::string v1_GlobalId, ::If
 ::Ifc4x3_rc4::IfcSpaceTypeEnum::Value Ifc4x3_rc4::IfcSpaceType::PredefinedType() const {  return ::Ifc4x3_rc4::IfcSpaceTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc4::IfcSpaceType::setPredefinedType(::Ifc4x3_rc4::IfcSpaceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcSpaceTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcSpaceType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcSpaceType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSpaceType::declaration() const { return *IFC4X3_RC4_IfcSpaceType_type; }
@@ -21438,7 +21438,7 @@ Ifc4x3_rc4::IfcSpaceType::IfcSpaceType(std::string v1_GlobalId, ::Ifc4x3_rc4::If
 
 // Function implementations for IfcSpatialElement
 boost::optional< std::string > Ifc4x3_rc4::IfcSpatialElement::LongName() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcSpatialElement::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc4::IfcRelContainedInSpatialStructure::list::ptr Ifc4x3_rc4::IfcSpatialElement::ContainsElements() const { return data_->getInverse(IFC4X3_RC4_IfcRelContainedInSpatialStructure_type, 5)->as<IfcRelContainedInSpatialStructure>(); }
 ::Ifc4x3_rc4::IfcRelServicesBuildings::list::ptr Ifc4x3_rc4::IfcSpatialElement::ServicedBySystems() const { return data_->getInverse(IFC4X3_RC4_IfcRelServicesBuildings_type, 5)->as<IfcRelServicesBuildings>(); }
@@ -21451,7 +21451,7 @@ Ifc4x3_rc4::IfcSpatialElement::IfcSpatialElement(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcSpatialElementType
 boost::optional< std::string > Ifc4x3_rc4::IfcSpatialElementType::ElementType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSpatialElementType::setElementType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSpatialElementType::declaration() const { return *IFC4X3_RC4_IfcSpatialElementType_type; }
@@ -21461,7 +21461,7 @@ Ifc4x3_rc4::IfcSpatialElementType::IfcSpatialElementType(std::string v1_GlobalId
 
 // Function implementations for IfcSpatialStructureElement
 boost::optional< ::Ifc4x3_rc4::IfcElementCompositionEnum::Value > Ifc4x3_rc4::IfcSpatialStructureElement::CompositionType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcElementCompositionEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x3_rc4::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElementCompositionEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSpatialStructureElement::setCompositionType(boost::optional< ::Ifc4x3_rc4::IfcElementCompositionEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcElementCompositionEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSpatialStructureElement::declaration() const { return *IFC4X3_RC4_IfcSpatialStructureElement_type; }
@@ -21479,7 +21479,7 @@ Ifc4x3_rc4::IfcSpatialStructureElementType::IfcSpatialStructureElementType(std::
 
 // Function implementations for IfcSpatialZone
 boost::optional< ::Ifc4x3_rc4::IfcSpatialZoneTypeEnum::Value > Ifc4x3_rc4::IfcSpatialZone::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSpatialZoneTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSpatialZone::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSpatialZoneTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSpatialZoneTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSpatialZone::declaration() const { return *IFC4X3_RC4_IfcSpatialZone_type; }
@@ -21491,7 +21491,7 @@ Ifc4x3_rc4::IfcSpatialZone::IfcSpatialZone(std::string v1_GlobalId, ::Ifc4x3_rc4
 ::Ifc4x3_rc4::IfcSpatialZoneTypeEnum::Value Ifc4x3_rc4::IfcSpatialZoneType::PredefinedType() const {  return ::Ifc4x3_rc4::IfcSpatialZoneTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc4::IfcSpatialZoneType::setPredefinedType(::Ifc4x3_rc4::IfcSpatialZoneTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcSpatialZoneTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcSpatialZoneType::LongName() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcSpatialZoneType::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSpatialZoneType::declaration() const { return *IFC4X3_RC4_IfcSpatialZoneType_type; }
@@ -21531,7 +21531,7 @@ Ifc4x3_rc4::IfcSpiral::IfcSpiral(::Ifc4x3_rc4::IfcAxis2Placement* v1_Position) :
 
 // Function implementations for IfcStackTerminal
 boost::optional< ::Ifc4x3_rc4::IfcStackTerminalTypeEnum::Value > Ifc4x3_rc4::IfcStackTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcStackTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcStackTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcStackTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcStackTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcStackTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStackTerminal::declaration() const { return *IFC4X3_RC4_IfcStackTerminal_type; }
@@ -21551,7 +21551,7 @@ Ifc4x3_rc4::IfcStackTerminalType::IfcStackTerminalType(std::string v1_GlobalId,
 
 // Function implementations for IfcStair
 boost::optional< ::Ifc4x3_rc4::IfcStairTypeEnum::Value > Ifc4x3_rc4::IfcStair::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcStairTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcStair::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcStairTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcStair::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcStairTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcStairTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStair::declaration() const { return *IFC4X3_RC4_IfcStair_type; }
@@ -21561,15 +21561,15 @@ Ifc4x3_rc4::IfcStair::IfcStair(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHi
 
 // Function implementations for IfcStairFlight
 boost::optional< int > Ifc4x3_rc4::IfcStairFlight::NumberOfRisers() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } int v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcStairFlight::setNumberOfRisers(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< int > Ifc4x3_rc4::IfcStairFlight::NumberOfTreads() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } int v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcStairFlight::setNumberOfTreads(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStairFlight::RiserHeight() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcStairFlight::setRiserHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStairFlight::TreadLength() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcStairFlight::setTreadLength(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcStairFlightTypeEnum::Value > Ifc4x3_rc4::IfcStairFlight::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcStairFlightTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc4::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcStairFlightTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcStairFlight::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcStairFlightTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcStairFlightTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStairFlight::declaration() const { return *IFC4X3_RC4_IfcStairFlight_type; }
@@ -21599,7 +21599,7 @@ Ifc4x3_rc4::IfcStairType::IfcStairType(std::string v1_GlobalId, ::Ifc4x3_rc4::If
 
 // Function implementations for IfcStructuralAction
 boost::optional< bool > Ifc4x3_rc4::IfcStructuralAction::DestabilizingLoad() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } bool v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcStructuralAction::setDestabilizingLoad(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralAction::declaration() const { return *IFC4X3_RC4_IfcStructuralAction_type; }
@@ -21626,9 +21626,9 @@ void Ifc4x3_rc4::IfcStructuralAnalysisModel::setPredefinedType(::Ifc4x3_rc4::Ifc
 ::Ifc4x3_rc4::IfcAxis2Placement3D* Ifc4x3_rc4::IfcStructuralAnalysisModel::OrientationOf2DPlane() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcAxis2Placement3D>(true); }
 void Ifc4x3_rc4::IfcStructuralAnalysisModel::setOrientationOf2DPlane(::Ifc4x3_rc4::IfcAxis2Placement3D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcStructuralLoadGroup >::ptr > Ifc4x3_rc4::IfcStructuralAnalysisModel::LoadedBy() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc4::IfcStructuralLoadGroup >(); }
-void Ifc4x3_rc4::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcStructuralAnalysisModel::setLoadedBy(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcStructuralLoadGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcStructuralResultGroup >::ptr > Ifc4x3_rc4::IfcStructuralAnalysisModel::HasResults() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(8); return es->as< ::Ifc4x3_rc4::IfcStructuralResultGroup >(); }
-void Ifc4x3_rc4::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcStructuralAnalysisModel::setHasResults(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcStructuralResultGroup >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(8,attr);} }
 ::Ifc4x3_rc4::IfcObjectPlacement* Ifc4x3_rc4::IfcStructuralAnalysisModel::SharedPlacement() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(9)))->as<::Ifc4x3_rc4::IfcObjectPlacement>(true); }
 void Ifc4x3_rc4::IfcStructuralAnalysisModel::setSharedPlacement(::Ifc4x3_rc4::IfcObjectPlacement* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 
@@ -21651,7 +21651,7 @@ Ifc4x3_rc4::IfcStructuralConnection::IfcStructuralConnection(std::string v1_Glob
 
 // Function implementations for IfcStructuralConnectionCondition
 boost::optional< std::string > Ifc4x3_rc4::IfcStructuralConnectionCondition::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcStructuralConnectionCondition::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralConnectionCondition::declaration() const { return *IFC4X3_RC4_IfcStructuralConnectionCondition_type; }
@@ -21661,7 +21661,7 @@ Ifc4x3_rc4::IfcStructuralConnectionCondition::IfcStructuralConnectionCondition(b
 
 // Function implementations for IfcStructuralCurveAction
 boost::optional< ::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::Value > Ifc4x3_rc4::IfcStructuralCurveAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcStructuralCurveAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc4::IfcStructuralCurveActivityTypeEnum::Value Ifc4x3_rc4::IfcStructuralCurveAction::PredefinedType() const {  return ::Ifc4x3_rc4::IfcStructuralCurveActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x3_rc4::IfcStructuralCurveAction::setPredefinedType(::Ifc4x3_rc4::IfcStructuralCurveActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcStructuralCurveActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -21730,7 +21730,7 @@ Ifc4x3_rc4::IfcStructuralLinearAction::IfcStructuralLinearAction(std::string v1_
 
 // Function implementations for IfcStructuralLoad
 boost::optional< std::string > Ifc4x3_rc4::IfcStructuralLoad::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoad::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralLoad::declaration() const { return *IFC4X3_RC4_IfcStructuralLoad_type; }
@@ -21740,7 +21740,7 @@ Ifc4x3_rc4::IfcStructuralLoad::IfcStructuralLoad(boost::optional< std::string >
 
 // Function implementations for IfcStructuralLoadCase
 boost::optional< std::vector< double > /*[3:3]*/ > Ifc4x3_rc4::IfcStructuralLoadCase::SelfWeightCoefficients() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::vector< double > /*[3:3]*/ v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadCase::setSelfWeightCoefficients(boost::optional< std::vector< double > /*[3:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralLoadCase::declaration() const { return *IFC4X3_RC4_IfcStructuralLoadCase_type; }
@@ -21752,7 +21752,7 @@ Ifc4x3_rc4::IfcStructuralLoadCase::IfcStructuralLoadCase(std::string v1_GlobalId
 aggregate_of< ::Ifc4x3_rc4::IfcStructuralLoadOrResult >::ptr Ifc4x3_rc4::IfcStructuralLoadConfiguration::Values() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc4::IfcStructuralLoadOrResult >(); }
 void Ifc4x3_rc4::IfcStructuralLoadConfiguration::setValues(aggregate_of< ::Ifc4x3_rc4::IfcStructuralLoadOrResult >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::vector< std::vector< double > > > Ifc4x3_rc4::IfcStructuralLoadConfiguration::Locations() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadConfiguration::setLocations(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralLoadConfiguration::declaration() const { return *IFC4X3_RC4_IfcStructuralLoadConfiguration_type; }
@@ -21768,9 +21768,9 @@ void Ifc4x3_rc4::IfcStructuralLoadGroup::setActionType(::Ifc4x3_rc4::IfcActionTy
 ::Ifc4x3_rc4::IfcActionSourceTypeEnum::Value Ifc4x3_rc4::IfcStructuralLoadGroup::ActionSource() const {  return ::Ifc4x3_rc4::IfcActionSourceTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc4::IfcStructuralLoadGroup::setActionSource(::Ifc4x3_rc4::IfcActionSourceTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcActionSourceTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadGroup::Coefficient() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadGroup::setCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcStructuralLoadGroup::Purpose() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadGroup::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 ::Ifc4x3_rc4::IfcStructuralResultGroup::list::ptr Ifc4x3_rc4::IfcStructuralLoadGroup::SourceOfResultGroup() const { return data_->getInverse(IFC4X3_RC4_IfcStructuralResultGroup_type, 6)->as<IfcStructuralResultGroup>(); }
 ::Ifc4x3_rc4::IfcStructuralAnalysisModel::list::ptr Ifc4x3_rc4::IfcStructuralLoadGroup::LoadGroupFor() const { return data_->getInverse(IFC4X3_RC4_IfcStructuralAnalysisModel_type, 7)->as<IfcStructuralAnalysisModel>(); }
@@ -21782,17 +21782,17 @@ Ifc4x3_rc4::IfcStructuralLoadGroup::IfcStructuralLoadGroup(std::string v1_Global
 
 // Function implementations for IfcStructuralLoadLinearForce
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadLinearForce::LinearForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadLinearForce::LinearForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadLinearForce::LinearForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadLinearForce::LinearMomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadLinearForce::LinearMomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadLinearForce::LinearMomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadLinearForce::setLinearMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralLoadLinearForce::declaration() const { return *IFC4X3_RC4_IfcStructuralLoadLinearForce_type; }
@@ -21810,11 +21810,11 @@ Ifc4x3_rc4::IfcStructuralLoadOrResult::IfcStructuralLoadOrResult(boost::optional
 
 // Function implementations for IfcStructuralLoadPlanarForce
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadPlanarForce::PlanarForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadPlanarForce::setPlanarForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadPlanarForce::PlanarForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadPlanarForce::setPlanarForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadPlanarForce::PlanarForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadPlanarForce::setPlanarForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralLoadPlanarForce::declaration() const { return *IFC4X3_RC4_IfcStructuralLoadPlanarForce_type; }
@@ -21824,17 +21824,17 @@ Ifc4x3_rc4::IfcStructuralLoadPlanarForce::IfcStructuralLoadPlanarForce(boost::op
 
 // Function implementations for IfcStructuralLoadSingleDisplacement
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::DisplacementX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setDisplacementX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::DisplacementY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setDisplacementY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::DisplacementZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setDisplacementZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::RotationalDisplacementRZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::setRotationalDisplacementRZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::declaration() const { return *IFC4X3_RC4_IfcStructuralLoadSingleDisplacement_type; }
@@ -21844,7 +21844,7 @@ Ifc4x3_rc4::IfcStructuralLoadSingleDisplacement::IfcStructuralLoadSingleDisplace
 
 // Function implementations for IfcStructuralLoadSingleDisplacementDistortion
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleDisplacementDistortion::Distortion() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleDisplacementDistortion::setDistortion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralLoadSingleDisplacementDistortion::declaration() const { return *IFC4X3_RC4_IfcStructuralLoadSingleDisplacementDistortion_type; }
@@ -21854,17 +21854,17 @@ Ifc4x3_rc4::IfcStructuralLoadSingleDisplacementDistortion::IfcStructuralLoadSing
 
 // Function implementations for IfcStructuralLoadSingleForce
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleForce::ForceX() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setForceX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleForce::ForceY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setForceY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleForce::ForceZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setForceZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleForce::MomentX() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setMomentX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleForce::MomentY() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setMomentY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleForce::MomentZ() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleForce::setMomentZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralLoadSingleForce::declaration() const { return *IFC4X3_RC4_IfcStructuralLoadSingleForce_type; }
@@ -21874,7 +21874,7 @@ Ifc4x3_rc4::IfcStructuralLoadSingleForce::IfcStructuralLoadSingleForce(boost::op
 
 // Function implementations for IfcStructuralLoadSingleForceWarping
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadSingleForceWarping::WarpingMoment() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadSingleForceWarping::setWarpingMoment(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralLoadSingleForceWarping::declaration() const { return *IFC4X3_RC4_IfcStructuralLoadSingleForceWarping_type; }
@@ -21892,11 +21892,11 @@ Ifc4x3_rc4::IfcStructuralLoadStatic::IfcStructuralLoadStatic(boost::optional< st
 
 // Function implementations for IfcStructuralLoadTemperature
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadTemperature::DeltaTConstant() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadTemperature::setDeltaTConstant(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadTemperature::DeltaTY() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadTemperature::setDeltaTY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralLoadTemperature::DeltaTZ() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcStructuralLoadTemperature::setDeltaTZ(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralLoadTemperature::declaration() const { return *IFC4X3_RC4_IfcStructuralLoadTemperature_type; }
@@ -21972,7 +21972,7 @@ Ifc4x3_rc4::IfcStructuralResultGroup::IfcStructuralResultGroup(std::string v1_Gl
 
 // Function implementations for IfcStructuralSurfaceAction
 boost::optional< ::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::Value > Ifc4x3_rc4::IfcStructuralSurfaceAction::ProjectedOrTrue() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcStructuralSurfaceAction::setProjectedOrTrue(boost::optional< ::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcProjectedOrTrueLengthEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc4::IfcStructuralSurfaceActivityTypeEnum::Value Ifc4x3_rc4::IfcStructuralSurfaceAction::PredefinedType() const {  return ::Ifc4x3_rc4::IfcStructuralSurfaceActivityTypeEnum::FromString(*data_->getArgument(11)); }
 void Ifc4x3_rc4::IfcStructuralSurfaceAction::setPredefinedType(::Ifc4x3_rc4::IfcStructuralSurfaceActivityTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcStructuralSurfaceActivityTypeEnum::ToString(v)));data_->setArgument(11,attr);} }
 
@@ -21994,7 +21994,7 @@ Ifc4x3_rc4::IfcStructuralSurfaceConnection::IfcStructuralSurfaceConnection(std::
 ::Ifc4x3_rc4::IfcStructuralSurfaceMemberTypeEnum::Value Ifc4x3_rc4::IfcStructuralSurfaceMember::PredefinedType() const {  return ::Ifc4x3_rc4::IfcStructuralSurfaceMemberTypeEnum::FromString(*data_->getArgument(7)); }
 void Ifc4x3_rc4::IfcStructuralSurfaceMember::setPredefinedType(::Ifc4x3_rc4::IfcStructuralSurfaceMemberTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcStructuralSurfaceMemberTypeEnum::ToString(v)));data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcStructuralSurfaceMember::Thickness() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcStructuralSurfaceMember::setThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStructuralSurfaceMember::declaration() const { return *IFC4X3_RC4_IfcStructuralSurfaceMember_type; }
@@ -22034,7 +22034,7 @@ void Ifc4x3_rc4::IfcStyledItem::setItem(::Ifc4x3_rc4::IfcRepresentationItem* v)
 aggregate_of< ::Ifc4x3_rc4::IfcPresentationStyle >::ptr Ifc4x3_rc4::IfcStyledItem::Styles() const {  aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc4::IfcPresentationStyle >(); }
 void Ifc4x3_rc4::IfcStyledItem::setStyles(aggregate_of< ::Ifc4x3_rc4::IfcPresentationStyle >::ptr v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((v)->generalize());data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcStyledItem::Name() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcStyledItem::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcStyledItem::declaration() const { return *IFC4X3_RC4_IfcStyledItem_type; }
@@ -22052,7 +22052,7 @@ Ifc4x3_rc4::IfcStyledRepresentation::IfcStyledRepresentation(::Ifc4x3_rc4::IfcRe
 
 // Function implementations for IfcSubContractResource
 boost::optional< ::Ifc4x3_rc4::IfcSubContractResourceTypeEnum::Value > Ifc4x3_rc4::IfcSubContractResource::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSubContractResourceTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSubContractResourceTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcSubContractResource::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSubContractResourceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSubContractResourceTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSubContractResource::declaration() const { return *IFC4X3_RC4_IfcSubContractResource_type; }
@@ -22114,7 +22114,7 @@ Ifc4x3_rc4::IfcSurfaceCurveSweptAreaSolid::IfcSurfaceCurveSweptAreaSolid(::Ifc4x
 
 // Function implementations for IfcSurfaceFeature
 boost::optional< ::Ifc4x3_rc4::IfcSurfaceFeatureTypeEnum::Value > Ifc4x3_rc4::IfcSurfaceFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSurfaceFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSurfaceFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSurfaceFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSurfaceFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSurfaceFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc4::IfcRelAdheresToElement::list::ptr Ifc4x3_rc4::IfcSurfaceFeature::AdheresToElement() const { return data_->getInverse(IFC4X3_RC4_IfcRelAdheresToElement_type, 5)->as<IfcRelAdheresToElement>(); }
 
@@ -22147,11 +22147,11 @@ Ifc4x3_rc4::IfcSurfaceOfRevolution::IfcSurfaceOfRevolution(::Ifc4x3_rc4::IfcProf
 
 // Function implementations for IfcSurfaceReinforcementArea
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x3_rc4::IfcSurfaceReinforcementArea::SurfaceReinforcement1() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcSurfaceReinforcementArea::setSurfaceReinforcement1(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[2:3]*/ > Ifc4x3_rc4::IfcSurfaceReinforcementArea::SurfaceReinforcement2() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[2:3]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcSurfaceReinforcementArea::setSurfaceReinforcement2(boost::optional< std::vector< double > /*[2:3]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSurfaceReinforcementArea::ShearReinforcement() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcSurfaceReinforcementArea::setShearReinforcement(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSurfaceReinforcementArea::declaration() const { return *IFC4X3_RC4_IfcSurfaceReinforcementArea_type; }
@@ -22189,9 +22189,9 @@ Ifc4x3_rc4::IfcSurfaceStyleLighting::IfcSurfaceStyleLighting(::Ifc4x3_rc4::IfcCo
 
 // Function implementations for IfcSurfaceStyleRefraction
 boost::optional< double > Ifc4x3_rc4::IfcSurfaceStyleRefraction::RefractionIndex() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } double v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcSurfaceStyleRefraction::setRefractionIndex(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSurfaceStyleRefraction::DispersionFactor() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcSurfaceStyleRefraction::setDispersionFactor(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSurfaceStyleRefraction::declaration() const { return *IFC4X3_RC4_IfcSurfaceStyleRefraction_type; }
@@ -22225,7 +22225,7 @@ Ifc4x3_rc4::IfcSurfaceStyleRendering::IfcSurfaceStyleRendering(::Ifc4x3_rc4::Ifc
 ::Ifc4x3_rc4::IfcColourRgb* Ifc4x3_rc4::IfcSurfaceStyleShading::SurfaceColour() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc4::IfcColourRgb>(true); }
 void Ifc4x3_rc4::IfcSurfaceStyleShading::setSurfaceColour(::Ifc4x3_rc4::IfcColourRgb* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSurfaceStyleShading::Transparency() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } double v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcSurfaceStyleShading::setTransparency(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSurfaceStyleShading::declaration() const { return *IFC4X3_RC4_IfcSurfaceStyleShading_type; }
@@ -22249,11 +22249,11 @@ void Ifc4x3_rc4::IfcSurfaceTexture::setRepeatS(bool v) { {IfcWrite::IfcWriteArgu
 bool Ifc4x3_rc4::IfcSurfaceTexture::RepeatT() const {  bool v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcSurfaceTexture::setRepeatT(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcSurfaceTexture::Mode() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcSurfaceTexture::setMode(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcCartesianTransformationOperator2D* Ifc4x3_rc4::IfcSurfaceTexture::TextureTransform() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcCartesianTransformationOperator2D>(true); }
 void Ifc4x3_rc4::IfcSurfaceTexture::setTextureTransform(::Ifc4x3_rc4::IfcCartesianTransformationOperator2D* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcSurfaceTexture::Parameter() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcSurfaceTexture::setParameter(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 ::Ifc4x3_rc4::IfcTextureCoordinate::list::ptr Ifc4x3_rc4::IfcSurfaceTexture::IsMappedBy() const { return data_->getInverse(IFC4X3_RC4_IfcTextureCoordinate_type, 0)->as<IfcTextureCoordinate>(); }
 ::Ifc4x3_rc4::IfcSurfaceStyleWithTextures::list::ptr Ifc4x3_rc4::IfcSurfaceTexture::UsedInStyles() const { return data_->getInverse(IFC4X3_RC4_IfcSurfaceStyleWithTextures_type, 0)->as<IfcSurfaceStyleWithTextures>(); }
@@ -22281,11 +22281,11 @@ void Ifc4x3_rc4::IfcSweptDiskSolid::setDirectrix(::Ifc4x3_rc4::IfcCurve* v) { {I
 double Ifc4x3_rc4::IfcSweptDiskSolid::Radius() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcSweptDiskSolid::setRadius(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSweptDiskSolid::InnerRadius() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcSweptDiskSolid::setInnerRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSweptDiskSolid::StartParam() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcSweptDiskSolid::setStartParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcSweptDiskSolid::EndParam() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcSweptDiskSolid::setEndParam(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSweptDiskSolid::declaration() const { return *IFC4X3_RC4_IfcSweptDiskSolid_type; }
@@ -22295,7 +22295,7 @@ Ifc4x3_rc4::IfcSweptDiskSolid::IfcSweptDiskSolid(::Ifc4x3_rc4::IfcCurve* v1_Dire
 
 // Function implementations for IfcSweptDiskSolidPolygonal
 boost::optional< double > Ifc4x3_rc4::IfcSweptDiskSolidPolygonal::FilletRadius() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcSweptDiskSolidPolygonal::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSweptDiskSolidPolygonal::declaration() const { return *IFC4X3_RC4_IfcSweptDiskSolidPolygonal_type; }
@@ -22317,7 +22317,7 @@ Ifc4x3_rc4::IfcSweptSurface::IfcSweptSurface(::Ifc4x3_rc4::IfcProfileDef* v1_Swe
 
 // Function implementations for IfcSwitchingDevice
 boost::optional< ::Ifc4x3_rc4::IfcSwitchingDeviceTypeEnum::Value > Ifc4x3_rc4::IfcSwitchingDevice::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSwitchingDeviceTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSwitchingDeviceTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSwitchingDevice::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSwitchingDeviceTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSwitchingDeviceTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSwitchingDevice::declaration() const { return *IFC4X3_RC4_IfcSwitchingDevice_type; }
@@ -22347,7 +22347,7 @@ Ifc4x3_rc4::IfcSystem::IfcSystem(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwner
 
 // Function implementations for IfcSystemFurnitureElement
 boost::optional< ::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x3_rc4::IfcSystemFurnitureElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcSystemFurnitureElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSystemFurnitureElement::declaration() const { return *IFC4X3_RC4_IfcSystemFurnitureElement_type; }
@@ -22357,7 +22357,7 @@ Ifc4x3_rc4::IfcSystemFurnitureElement::IfcSystemFurnitureElement(std::string v1_
 
 // Function implementations for IfcSystemFurnitureElementType
 boost::optional< ::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::Value > Ifc4x3_rc4::IfcSystemFurnitureElementType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcSystemFurnitureElementType::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcSystemFurnitureElementTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcSystemFurnitureElementType::declaration() const { return *IFC4X3_RC4_IfcSystemFurnitureElementType_type; }
@@ -22375,15 +22375,15 @@ void Ifc4x3_rc4::IfcTShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc4::IfcTShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcTShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcTShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTShapeProfileDef::FlangeEdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcTShapeProfileDef::setFlangeEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTShapeProfileDef::WebEdgeRadius() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcTShapeProfileDef::setWebEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTShapeProfileDef::WebSlope() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcTShapeProfileDef::setWebSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcTShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTShapeProfileDef::declaration() const { return *IFC4X3_RC4_IfcTShapeProfileDef_type; }
@@ -22393,11 +22393,11 @@ Ifc4x3_rc4::IfcTShapeProfileDef::IfcTShapeProfileDef(::Ifc4x3_rc4::IfcProfileTyp
 
 // Function implementations for IfcTable
 boost::optional< std::string > Ifc4x3_rc4::IfcTable::Name() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcTable::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcTableRow >::ptr > Ifc4x3_rc4::IfcTable::Rows() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(1); return es->as< ::Ifc4x3_rc4::IfcTableRow >(); }
-void Ifc4x3_rc4::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcTable::setRows(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcTableRow >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(1,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcTableColumn >::ptr > Ifc4x3_rc4::IfcTable::Columns() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(2); return es->as< ::Ifc4x3_rc4::IfcTableColumn >(); }
-void Ifc4x3_rc4::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcTable::setColumns(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcTableColumn >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTable::declaration() const { return *IFC4X3_RC4_IfcTable_type; }
@@ -22407,11 +22407,11 @@ Ifc4x3_rc4::IfcTable::IfcTable(boost::optional< std::string > v1_Name, boost::op
 
 // Function implementations for IfcTableColumn
 boost::optional< std::string > Ifc4x3_rc4::IfcTableColumn::Identifier() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } std::string v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcTableColumn::setIdentifier(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTableColumn::Name() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcTableColumn::setName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTableColumn::Description() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcTableColumn::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcUnit* Ifc4x3_rc4::IfcTableColumn::Unit() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcUnit>(true); }
 void Ifc4x3_rc4::IfcTableColumn::setUnit(::Ifc4x3_rc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc4::IfcReference* Ifc4x3_rc4::IfcTableColumn::ReferencePath() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc4::IfcReference>(true); }
@@ -22425,9 +22425,9 @@ Ifc4x3_rc4::IfcTableColumn::IfcTableColumn(boost::optional< std::string > v1_Ide
 
 // Function implementations for IfcTableRow
 boost::optional< aggregate_of_instance::ptr > Ifc4x3_rc4::IfcTableRow::RowCells() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return boost::none; } aggregate_of_instance::ptr v = *data_->getArgument(0); return v; }
-void Ifc4x3_rc4::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(0,attr);} }
+void Ifc4x3_rc4::IfcTableRow::setRowCells(boost::optional< aggregate_of_instance::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(0,attr);} }
 boost::optional< bool > Ifc4x3_rc4::IfcTableRow::IsHeading() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } bool v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcTableRow::setIsHeading(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTableRow::declaration() const { return *IFC4X3_RC4_IfcTableRow_type; }
@@ -22437,7 +22437,7 @@ Ifc4x3_rc4::IfcTableRow::IfcTableRow(boost::optional< aggregate_of_instance::ptr
 
 // Function implementations for IfcTank
 boost::optional< ::Ifc4x3_rc4::IfcTankTypeEnum::Value > Ifc4x3_rc4::IfcTank::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcTankTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcTank::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTankTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcTank::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTankTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTankTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTank::declaration() const { return *IFC4X3_RC4_IfcTank_type; }
@@ -22457,17 +22457,17 @@ Ifc4x3_rc4::IfcTankType::IfcTankType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcTask
 boost::optional< std::string > Ifc4x3_rc4::IfcTask::Status() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcTask::setStatus(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTask::WorkMethod() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcTask::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 bool Ifc4x3_rc4::IfcTask::IsMilestone() const {  bool v = *data_->getArgument(9); return v; }
 void Ifc4x3_rc4::IfcTask::setIsMilestone(bool v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(9,attr);} }
 boost::optional< int > Ifc4x3_rc4::IfcTask::Priority() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } int v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcTask::setPriority(boost::optional< int > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 ::Ifc4x3_rc4::IfcTaskTime* Ifc4x3_rc4::IfcTask::TaskTime() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(11)))->as<::Ifc4x3_rc4::IfcTaskTime>(true); }
 void Ifc4x3_rc4::IfcTask::setTaskTime(::Ifc4x3_rc4::IfcTaskTime* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcTaskTypeEnum::Value > Ifc4x3_rc4::IfcTask::PredefinedType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcTaskTypeEnum::FromString(*data_->getArgument(12)); }
-void Ifc4x3_rc4::IfcTask::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTaskTypeEnum::ToString(*v)));data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcTask::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTaskTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTaskTypeEnum::ToString(*v)));}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTask::declaration() const { return *IFC4X3_RC4_IfcTask_type; }
@@ -22477,39 +22477,39 @@ Ifc4x3_rc4::IfcTask::IfcTask(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwnerHist
 
 // Function implementations for IfcTaskTime
 boost::optional< ::Ifc4x3_rc4::IfcTaskDurationEnum::Value > Ifc4x3_rc4::IfcTaskTime::DurationType() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcTaskDurationEnum::FromString(*data_->getArgument(3)); }
-void Ifc4x3_rc4::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x3_rc4::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTaskDurationEnum::ToString(*v)));data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setDurationType(boost::optional< ::Ifc4x3_rc4::IfcTaskDurationEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTaskDurationEnum::ToString(*v)));}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::ScheduleDuration() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setScheduleDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::ScheduleStart() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setScheduleStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::ScheduleFinish() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setScheduleFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::EarlyStart() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setEarlyStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::EarlyFinish() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setEarlyFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::LateStart() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setLateStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::LateFinish() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setLateFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::FreeFloat() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } std::string v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setFreeFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::TotalFloat() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< bool > Ifc4x3_rc4::IfcTaskTime::IsCritical() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } bool v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setIsCritical(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::StatusTime() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } std::string v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setStatusTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::ActualDuration() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } std::string v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setActualDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::ActualStart() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } std::string v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setActualStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::ActualFinish() const { if(!data_->getArgument(17) || data_->getArgument(17)->isNull()) { return boost::none; } std::string v = *data_->getArgument(17); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(17,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setActualFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(17,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskTime::RemainingTime() const { if(!data_->getArgument(18) || data_->getArgument(18)->isNull()) { return boost::none; } std::string v = *data_->getArgument(18); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(18,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setRemainingTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(18,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTaskTime::Completion() const { if(!data_->getArgument(19) || data_->getArgument(19)->isNull()) { return boost::none; } double v = *data_->getArgument(19); return v; }
-void Ifc4x3_rc4::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(19,attr);} }
+void Ifc4x3_rc4::IfcTaskTime::setCompletion(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(19,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTaskTime::declaration() const { return *IFC4X3_RC4_IfcTaskTime_type; }
@@ -22531,7 +22531,7 @@ Ifc4x3_rc4::IfcTaskTimeRecurring::IfcTaskTimeRecurring(boost::optional< std::str
 ::Ifc4x3_rc4::IfcTaskTypeEnum::Value Ifc4x3_rc4::IfcTaskType::PredefinedType() const {  return ::Ifc4x3_rc4::IfcTaskTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc4::IfcTaskType::setPredefinedType(::Ifc4x3_rc4::IfcTaskTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcTaskTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTaskType::WorkMethod() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcTaskType::setWorkMethod(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTaskType::declaration() const { return *IFC4X3_RC4_IfcTaskType_type; }
@@ -22541,17 +22541,17 @@ Ifc4x3_rc4::IfcTaskType::IfcTaskType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcTelecomAddress
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcTelecomAddress::TelephoneNumbers() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcTelecomAddress::setTelephoneNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcTelecomAddress::FacsimileNumbers() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcTelecomAddress::setFacsimileNumbers(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTelecomAddress::PagerNumber() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcTelecomAddress::setPagerNumber(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcTelecomAddress::ElectronicMailAddresses() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcTelecomAddress::setElectronicMailAddresses(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTelecomAddress::WWWHomePageURL() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcTelecomAddress::setWWWHomePageURL(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::vector< std::string > /*[1:?]*/ > Ifc4x3_rc4::IfcTelecomAddress::MessagingIDs() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcTelecomAddress::setMessagingIDs(boost::optional< std::vector< std::string > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTelecomAddress::declaration() const { return *IFC4X3_RC4_IfcTelecomAddress_type; }
@@ -22561,21 +22561,21 @@ Ifc4x3_rc4::IfcTelecomAddress::IfcTelecomAddress(boost::optional< ::Ifc4x3_rc4::
 
 // Function implementations for IfcTendon
 boost::optional< ::Ifc4x3_rc4::IfcTendonTypeEnum::Value > Ifc4x3_rc4::IfcTendon::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTendonTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcTendon::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTendonTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTendonTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTendon::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcTendon::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTendon::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcTendon::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTendon::TensionForce() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcTendon::setTensionForce(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTendon::PreStress() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc4::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcTendon::setPreStress(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTendon::FrictionCoefficient() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc4::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc4::IfcTendon::setFrictionCoefficient(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTendon::AnchorageSlip() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc4::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc4::IfcTendon::setAnchorageSlip(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTendon::MinCurvatureRadius() const { if(!data_->getArgument(16) || data_->getArgument(16)->isNull()) { return boost::none; } double v = *data_->getArgument(16); return v; }
-void Ifc4x3_rc4::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(16,attr);} }
+void Ifc4x3_rc4::IfcTendon::setMinCurvatureRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(16,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTendon::declaration() const { return *IFC4X3_RC4_IfcTendon_type; }
@@ -22585,7 +22585,7 @@ Ifc4x3_rc4::IfcTendon::IfcTendon(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwner
 
 // Function implementations for IfcTendonAnchor
 boost::optional< ::Ifc4x3_rc4::IfcTendonAnchorTypeEnum::Value > Ifc4x3_rc4::IfcTendonAnchor::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcTendonAnchorTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTendonAnchorTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcTendonAnchor::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTendonAnchorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTendonAnchorTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTendonAnchor::declaration() const { return *IFC4X3_RC4_IfcTendonAnchor_type; }
@@ -22627,11 +22627,11 @@ Ifc4x3_rc4::IfcTendonConduitType::IfcTendonConduitType(std::string v1_GlobalId,
 ::Ifc4x3_rc4::IfcTendonTypeEnum::Value Ifc4x3_rc4::IfcTendonType::PredefinedType() const {  return ::Ifc4x3_rc4::IfcTendonTypeEnum::FromString(*data_->getArgument(9)); }
 void Ifc4x3_rc4::IfcTendonType::setPredefinedType(::Ifc4x3_rc4::IfcTendonTypeEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcTendonTypeEnum::ToString(v)));data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTendonType::NominalDiameter() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcTendonType::setNominalDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTendonType::CrossSectionArea() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcTendonType::setCrossSectionArea(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcTendonType::SheathDiameter() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } double v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcTendonType::setSheathDiameter(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTendonType::declaration() const { return *IFC4X3_RC4_IfcTendonType_type; }
@@ -22693,7 +22693,7 @@ void Ifc4x3_rc4::IfcTextStyle::setTextStyle(::Ifc4x3_rc4::IfcTextStyleTextModel*
 ::Ifc4x3_rc4::IfcTextFontSelect* Ifc4x3_rc4::IfcTextStyle::TextFontStyle() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcTextFontSelect>(true); }
 void Ifc4x3_rc4::IfcTextStyle::setTextFontStyle(::Ifc4x3_rc4::IfcTextFontSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< bool > Ifc4x3_rc4::IfcTextStyle::ModelOrDraughting() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } bool v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcTextStyle::setModelOrDraughting(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTextStyle::declaration() const { return *IFC4X3_RC4_IfcTextStyle_type; }
@@ -22705,11 +22705,11 @@ Ifc4x3_rc4::IfcTextStyle::IfcTextStyle(boost::optional< std::string > v1_Name, :
 std::vector< std::string > /*[1:?]*/ Ifc4x3_rc4::IfcTextStyleFontModel::FontFamily() const {  std::vector< std::string > /*[1:?]*/ v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcTextStyleFontModel::setFontFamily(std::vector< std::string > /*[1:?]*/ v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTextStyleFontModel::FontStyle() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcTextStyleFontModel::setFontStyle(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTextStyleFontModel::FontVariant() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } std::string v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcTextStyleFontModel::setFontVariant(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTextStyleFontModel::FontWeight() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcTextStyleFontModel::setFontWeight(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 ::Ifc4x3_rc4::IfcSizeSelect* Ifc4x3_rc4::IfcTextStyleFontModel::FontSize() const {  return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(5)))->as<::Ifc4x3_rc4::IfcSizeSelect>(true); }
 void Ifc4x3_rc4::IfcTextStyleFontModel::setFontSize(::Ifc4x3_rc4::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(5,attr);} }
 
@@ -22735,15 +22735,15 @@ Ifc4x3_rc4::IfcTextStyleForDefinedFont::IfcTextStyleForDefinedFont(::Ifc4x3_rc4:
 ::Ifc4x3_rc4::IfcSizeSelect* Ifc4x3_rc4::IfcTextStyleTextModel::TextIndent() const { if(!data_->getArgument(0) || data_->getArgument(0)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(0)))->as<::Ifc4x3_rc4::IfcSizeSelect>(true); }
 void Ifc4x3_rc4::IfcTextStyleTextModel::setTextIndent(::Ifc4x3_rc4::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTextStyleTextModel::TextAlign() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcTextStyleTextModel::setTextAlign(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTextStyleTextModel::TextDecoration() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::string v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcTextStyleTextModel::setTextDecoration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 ::Ifc4x3_rc4::IfcSizeSelect* Ifc4x3_rc4::IfcTextStyleTextModel::LetterSpacing() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcSizeSelect>(true); }
 void Ifc4x3_rc4::IfcTextStyleTextModel::setLetterSpacing(::Ifc4x3_rc4::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 ::Ifc4x3_rc4::IfcSizeSelect* Ifc4x3_rc4::IfcTextStyleTextModel::WordSpacing() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(4)))->as<::Ifc4x3_rc4::IfcSizeSelect>(true); }
 void Ifc4x3_rc4::IfcTextStyleTextModel::setWordSpacing(::Ifc4x3_rc4::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTextStyleTextModel::TextTransform() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcTextStyleTextModel::setTextTransform(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 ::Ifc4x3_rc4::IfcSizeSelect* Ifc4x3_rc4::IfcTextStyleTextModel::LineHeight() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(6)))->as<::Ifc4x3_rc4::IfcSizeSelect>(true); }
 void Ifc4x3_rc4::IfcTextStyleTextModel::setLineHeight(::Ifc4x3_rc4::IfcSizeSelect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 
@@ -22767,7 +22767,7 @@ Ifc4x3_rc4::IfcTextureCoordinate::IfcTextureCoordinate(aggregate_of< ::Ifc4x3_rc
 std::string Ifc4x3_rc4::IfcTextureCoordinateGenerator::Mode() const {  std::string v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcTextureCoordinateGenerator::setMode(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< std::vector< double > /*[1:?]*/ > Ifc4x3_rc4::IfcTextureCoordinateGenerator::Parameter() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } std::vector< double > /*[1:?]*/ v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcTextureCoordinateGenerator::setParameter(boost::optional< std::vector< double > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTextureCoordinateGenerator::declaration() const { return *IFC4X3_RC4_IfcTextureCoordinateGenerator_type; }
@@ -22811,11 +22811,11 @@ Ifc4x3_rc4::IfcTextureVertexList::IfcTextureVertexList(std::vector< std::vector<
 double Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::CubicTerm() const {  double v = *data_->getArgument(1); return v; }
 void Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::setCubicTerm(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(1,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::QuadraticTerm() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } double v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::setQuadraticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::setQuadraticTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::LinearTerm() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return boost::none; } double v = *data_->getArgument(3); return v; }
-void Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(3,attr);} }
+void Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::setLinearTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(3,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::ConstantTerm() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::setConstantTerm(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcThirdOrderPolynomialSpiral::declaration() const { return *IFC4X3_RC4_IfcThirdOrderPolynomialSpiral_type; }
@@ -22839,7 +22839,7 @@ Ifc4x3_rc4::IfcTimePeriod::IfcTimePeriod(std::string v1_StartTime, std::string v
 std::string Ifc4x3_rc4::IfcTimeSeries::Name() const {  std::string v = *data_->getArgument(0); return v; }
 void Ifc4x3_rc4::IfcTimeSeries::setName(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(0,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTimeSeries::Description() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::string v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcTimeSeries::setDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 std::string Ifc4x3_rc4::IfcTimeSeries::StartTime() const {  std::string v = *data_->getArgument(2); return v; }
 void Ifc4x3_rc4::IfcTimeSeries::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(2,attr);} }
 std::string Ifc4x3_rc4::IfcTimeSeries::EndTime() const {  std::string v = *data_->getArgument(3); return v; }
@@ -22849,7 +22849,7 @@ void Ifc4x3_rc4::IfcTimeSeries::setTimeSeriesDataType(::Ifc4x3_rc4::IfcTimeSerie
 ::Ifc4x3_rc4::IfcDataOriginEnum::Value Ifc4x3_rc4::IfcTimeSeries::DataOrigin() const {  return ::Ifc4x3_rc4::IfcDataOriginEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc4::IfcTimeSeries::setDataOrigin(::Ifc4x3_rc4::IfcDataOriginEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcDataOriginEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTimeSeries::UserDefinedDataOrigin() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcTimeSeries::setUserDefinedDataOrigin(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 ::Ifc4x3_rc4::IfcUnit* Ifc4x3_rc4::IfcTimeSeries::Unit() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(7)))->as<::Ifc4x3_rc4::IfcUnit>(true); }
 void Ifc4x3_rc4::IfcTimeSeries::setUnit(::Ifc4x3_rc4::IfcUnit* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(7,attr);} }
 
@@ -22900,7 +22900,7 @@ Ifc4x3_rc4::IfcToroidalSurface::IfcToroidalSurface(::Ifc4x3_rc4::IfcAxis2Placeme
 
 // Function implementations for IfcTrackElement
 boost::optional< ::Ifc4x3_rc4::IfcTrackElementTypeEnum::Value > Ifc4x3_rc4::IfcTrackElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcTrackElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcTrackElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTrackElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTrackElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcTrackElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTrackElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTrackElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTrackElement::declaration() const { return *IFC4X3_RC4_IfcTrackElement_type; }
@@ -22920,7 +22920,7 @@ Ifc4x3_rc4::IfcTrackElementType::IfcTrackElementType(std::string v1_GlobalId, ::
 
 // Function implementations for IfcTransformer
 boost::optional< ::Ifc4x3_rc4::IfcTransformerTypeEnum::Value > Ifc4x3_rc4::IfcTransformer::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcTransformerTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTransformerTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcTransformer::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTransformerTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTransformerTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTransformer::declaration() const { return *IFC4X3_RC4_IfcTransformer_type; }
@@ -22976,13 +22976,13 @@ Ifc4x3_rc4::IfcTrapeziumProfileDef::IfcTrapeziumProfileDef(::Ifc4x3_rc4::IfcProf
 
 // Function implementations for IfcTriangulatedFaceSet
 boost::optional< std::vector< std::vector< double > > > Ifc4x3_rc4::IfcTriangulatedFaceSet::Normals() const { if(!data_->getArgument(1) || data_->getArgument(1)->isNull()) { return boost::none; } std::vector< std::vector< double > > v = *data_->getArgument(1); return v; }
-void Ifc4x3_rc4::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(1,attr);} }
+void Ifc4x3_rc4::IfcTriangulatedFaceSet::setNormals(boost::optional< std::vector< std::vector< double > > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(1,attr);} }
 boost::optional< bool > Ifc4x3_rc4::IfcTriangulatedFaceSet::Closed() const { if(!data_->getArgument(2) || data_->getArgument(2)->isNull()) { return boost::none; } bool v = *data_->getArgument(2); return v; }
-void Ifc4x3_rc4::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(2,attr);} }
+void Ifc4x3_rc4::IfcTriangulatedFaceSet::setClosed(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(2,attr);} }
 std::vector< std::vector< int > > Ifc4x3_rc4::IfcTriangulatedFaceSet::CoordIndex() const {  std::vector< std::vector< int > > v = *data_->getArgument(3); return v; }
 void Ifc4x3_rc4::IfcTriangulatedFaceSet::setCoordIndex(std::vector< std::vector< int > > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::vector< int > /*[1:?]*/ > Ifc4x3_rc4::IfcTriangulatedFaceSet::PnIndex() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::vector< int > /*[1:?]*/ v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcTriangulatedFaceSet::setPnIndex(boost::optional< std::vector< int > /*[1:?]*/ > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTriangulatedFaceSet::declaration() const { return *IFC4X3_RC4_IfcTriangulatedFaceSet_type; }
@@ -23020,7 +23020,7 @@ Ifc4x3_rc4::IfcTrimmedCurve::IfcTrimmedCurve(::Ifc4x3_rc4::IfcCurve* v1_BasisCur
 
 // Function implementations for IfcTubeBundle
 boost::optional< ::Ifc4x3_rc4::IfcTubeBundleTypeEnum::Value > Ifc4x3_rc4::IfcTubeBundle::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcTubeBundleTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTubeBundleTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcTubeBundle::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcTubeBundleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcTubeBundleTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcTubeBundle::declaration() const { return *IFC4X3_RC4_IfcTubeBundle_type; }
@@ -23040,9 +23040,9 @@ Ifc4x3_rc4::IfcTubeBundleType::IfcTubeBundleType(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcTypeObject
 boost::optional< std::string > Ifc4x3_rc4::IfcTypeObject::ApplicableOccurrence() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcTypeObject::setApplicableOccurrence(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPropertySetDefinition >::ptr > Ifc4x3_rc4::IfcTypeObject::HasPropertySets() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(5); return es->as< ::Ifc4x3_rc4::IfcPropertySetDefinition >(); }
-void Ifc4x3_rc4::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcTypeObject::setHasPropertySets(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPropertySetDefinition >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(5,attr);} }
 
 ::Ifc4x3_rc4::IfcRelDefinesByType::list::ptr Ifc4x3_rc4::IfcTypeObject::Types() const { return data_->getInverse(IFC4X3_RC4_IfcRelDefinesByType_type, 5)->as<IfcRelDefinesByType>(); }
 
@@ -23053,11 +23053,11 @@ Ifc4x3_rc4::IfcTypeObject::IfcTypeObject(std::string v1_GlobalId, ::Ifc4x3_rc4::
 
 // Function implementations for IfcTypeProcess
 boost::optional< std::string > Ifc4x3_rc4::IfcTypeProcess::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcTypeProcess::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTypeProcess::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcTypeProcess::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTypeProcess::ProcessType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcTypeProcess::setProcessType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc4::IfcRelAssignsToProcess::list::ptr Ifc4x3_rc4::IfcTypeProcess::OperatesOn() const { return data_->getInverse(IFC4X3_RC4_IfcRelAssignsToProcess_type, 6)->as<IfcRelAssignsToProcess>(); }
 
@@ -23068,9 +23068,9 @@ Ifc4x3_rc4::IfcTypeProcess::IfcTypeProcess(std::string v1_GlobalId, ::Ifc4x3_rc4
 
 // Function implementations for IfcTypeProduct
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcRepresentationMap >::ptr > Ifc4x3_rc4::IfcTypeProduct::RepresentationMaps() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc4::IfcRepresentationMap >(); }
-void Ifc4x3_rc4::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcTypeProduct::setRepresentationMaps(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcRepresentationMap >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTypeProduct::Tag() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcTypeProduct::setTag(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 
 ::Ifc4x3_rc4::IfcRelAssignsToProduct::list::ptr Ifc4x3_rc4::IfcTypeProduct::ReferencedBy() const { return data_->getInverse(IFC4X3_RC4_IfcRelAssignsToProduct_type, 6)->as<IfcRelAssignsToProduct>(); }
 
@@ -23081,11 +23081,11 @@ Ifc4x3_rc4::IfcTypeProduct::IfcTypeProduct(std::string v1_GlobalId, ::Ifc4x3_rc4
 
 // Function implementations for IfcTypeResource
 boost::optional< std::string > Ifc4x3_rc4::IfcTypeResource::Identification() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } std::string v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcTypeResource::setIdentification(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTypeResource::LongDescription() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } std::string v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcTypeResource::setLongDescription(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcTypeResource::ResourceType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcTypeResource::setResourceType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 ::Ifc4x3_rc4::IfcRelAssignsToResource::list::ptr Ifc4x3_rc4::IfcTypeResource::ResourceOf() const { return data_->getInverse(IFC4X3_RC4_IfcRelAssignsToResource_type, 6)->as<IfcRelAssignsToResource>(); }
 
@@ -23104,11 +23104,11 @@ void Ifc4x3_rc4::IfcUShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc4::IfcUShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcUShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcUShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcUShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcUShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcUShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcUShapeProfileDef::FlangeSlope() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcUShapeProfileDef::setFlangeSlope(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcUShapeProfileDef::declaration() const { return *IFC4X3_RC4_IfcUShapeProfileDef_type; }
@@ -23128,7 +23128,7 @@ Ifc4x3_rc4::IfcUnitAssignment::IfcUnitAssignment(aggregate_of_instance::ptr v1_U
 
 // Function implementations for IfcUnitaryControlElement
 boost::optional< ::Ifc4x3_rc4::IfcUnitaryControlElementTypeEnum::Value > Ifc4x3_rc4::IfcUnitaryControlElement::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcUnitaryControlElementTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcUnitaryControlElementTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcUnitaryControlElement::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcUnitaryControlElementTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcUnitaryControlElementTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcUnitaryControlElement::declaration() const { return *IFC4X3_RC4_IfcUnitaryControlElement_type; }
@@ -23148,7 +23148,7 @@ Ifc4x3_rc4::IfcUnitaryControlElementType::IfcUnitaryControlElementType(std::stri
 
 // Function implementations for IfcUnitaryEquipment
 boost::optional< ::Ifc4x3_rc4::IfcUnitaryEquipmentTypeEnum::Value > Ifc4x3_rc4::IfcUnitaryEquipment::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcUnitaryEquipmentTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcUnitaryEquipmentTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcUnitaryEquipment::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcUnitaryEquipmentTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcUnitaryEquipmentTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcUnitaryEquipment::declaration() const { return *IFC4X3_RC4_IfcUnitaryEquipment_type; }
@@ -23168,7 +23168,7 @@ Ifc4x3_rc4::IfcUnitaryEquipmentType::IfcUnitaryEquipmentType(std::string v1_Glob
 
 // Function implementations for IfcValve
 boost::optional< ::Ifc4x3_rc4::IfcValveTypeEnum::Value > Ifc4x3_rc4::IfcValve::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcValveTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcValve::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcValveTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcValve::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcValveTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcValveTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcValve::declaration() const { return *IFC4X3_RC4_IfcValve_type; }
@@ -23228,7 +23228,7 @@ Ifc4x3_rc4::IfcVertexPoint::IfcVertexPoint(::Ifc4x3_rc4::IfcPoint* v1_VertexGeom
 
 // Function implementations for IfcVibrationDamper
 boost::optional< ::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::Value > Ifc4x3_rc4::IfcVibrationDamper::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcVibrationDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcVibrationDamper::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcVibrationDamper::declaration() const { return *IFC4X3_RC4_IfcVibrationDamper_type; }
@@ -23238,7 +23238,7 @@ Ifc4x3_rc4::IfcVibrationDamper::IfcVibrationDamper(std::string v1_GlobalId, ::If
 
 // Function implementations for IfcVibrationDamperType
 boost::optional< ::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::Value > Ifc4x3_rc4::IfcVibrationDamperType::PredefinedType() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::FromString(*data_->getArgument(9)); }
-void Ifc4x3_rc4::IfcVibrationDamperType::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::ToString(*v)));data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcVibrationDamperType::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcVibrationDamperTypeEnum::ToString(*v)));}data_->setArgument(9,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcVibrationDamperType::declaration() const { return *IFC4X3_RC4_IfcVibrationDamperType_type; }
@@ -23248,7 +23248,7 @@ Ifc4x3_rc4::IfcVibrationDamperType::IfcVibrationDamperType(std::string v1_Global
 
 // Function implementations for IfcVibrationIsolator
 boost::optional< ::Ifc4x3_rc4::IfcVibrationIsolatorTypeEnum::Value > Ifc4x3_rc4::IfcVibrationIsolator::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcVibrationIsolatorTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcVibrationIsolatorTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcVibrationIsolator::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcVibrationIsolatorTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcVibrationIsolatorTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcVibrationIsolator::declaration() const { return *IFC4X3_RC4_IfcVibrationIsolator_type; }
@@ -23296,7 +23296,7 @@ Ifc4x3_rc4::IfcVoidStratum::IfcVoidStratum(std::string v1_GlobalId, ::Ifc4x3_rc4
 
 // Function implementations for IfcVoidingFeature
 boost::optional< ::Ifc4x3_rc4::IfcVoidingFeatureTypeEnum::Value > Ifc4x3_rc4::IfcVoidingFeature::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcVoidingFeatureTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcVoidingFeatureTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcVoidingFeature::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcVoidingFeatureTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcVoidingFeatureTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcVoidingFeature::declaration() const { return *IFC4X3_RC4_IfcVoidingFeature_type; }
@@ -23306,7 +23306,7 @@ Ifc4x3_rc4::IfcVoidingFeature::IfcVoidingFeature(std::string v1_GlobalId, ::Ifc4
 
 // Function implementations for IfcWall
 boost::optional< ::Ifc4x3_rc4::IfcWallTypeEnum::Value > Ifc4x3_rc4::IfcWall::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcWallTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcWall::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWallTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcWall::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWallTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWallTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcWall::declaration() const { return *IFC4X3_RC4_IfcWall_type; }
@@ -23342,7 +23342,7 @@ Ifc4x3_rc4::IfcWallType::IfcWallType(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcWasteTerminal
 boost::optional< ::Ifc4x3_rc4::IfcWasteTerminalTypeEnum::Value > Ifc4x3_rc4::IfcWasteTerminal::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcWasteTerminalTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWasteTerminalTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcWasteTerminal::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWasteTerminalTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWasteTerminalTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcWasteTerminal::declaration() const { return *IFC4X3_RC4_IfcWasteTerminal_type; }
@@ -23370,15 +23370,15 @@ Ifc4x3_rc4::IfcWaterStratum::IfcWaterStratum(std::string v1_GlobalId, ::Ifc4x3_r
 
 // Function implementations for IfcWindow
 boost::optional< double > Ifc4x3_rc4::IfcWindow::OverallHeight() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcWindow::setOverallHeight(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindow::OverallWidth() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcWindow::setOverallWidth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcWindowTypeEnum::Value > Ifc4x3_rc4::IfcWindow::PredefinedType() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcWindowTypeEnum::FromString(*data_->getArgument(10)); }
-void Ifc4x3_rc4::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWindowTypeEnum::ToString(*v)));data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcWindow::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWindowTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWindowTypeEnum::ToString(*v)));}data_->setArgument(10,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcWindowTypePartitioningEnum::Value > Ifc4x3_rc4::IfcWindow::PartitioningType() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(11)); }
-void Ifc4x3_rc4::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x3_rc4::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWindowTypePartitioningEnum::ToString(*v)));data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcWindow::setPartitioningType(boost::optional< ::Ifc4x3_rc4::IfcWindowTypePartitioningEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWindowTypePartitioningEnum::ToString(*v)));}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcWindow::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcWindow::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcWindow::declaration() const { return *IFC4X3_RC4_IfcWindow_type; }
@@ -23388,29 +23388,29 @@ Ifc4x3_rc4::IfcWindow::IfcWindow(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcOwner
 
 // Function implementations for IfcWindowLiningProperties
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::LiningDepth() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } double v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setLiningDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::LiningThickness() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } double v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setLiningThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::TransomThickness() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setTransomThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::MullionThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setMullionThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::FirstTransomOffset() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setFirstTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::SecondTransomOffset() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } double v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setSecondTransomOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::FirstMullionOffset() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } double v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setFirstMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::SecondMullionOffset() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } double v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setSecondMullionOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 ::Ifc4x3_rc4::IfcShapeAspect* Ifc4x3_rc4::IfcWindowLiningProperties::ShapeAspectStyle() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(12)))->as<::Ifc4x3_rc4::IfcShapeAspect>(true); }
 void Ifc4x3_rc4::IfcWindowLiningProperties::setShapeAspectStyle(::Ifc4x3_rc4::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(12,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::LiningOffset() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } double v = *data_->getArgument(13); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setLiningOffset(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(13,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::LiningToPanelOffsetX() const { if(!data_->getArgument(14) || data_->getArgument(14)->isNull()) { return boost::none; } double v = *data_->getArgument(14); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(14,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setLiningToPanelOffsetX(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(14,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowLiningProperties::LiningToPanelOffsetY() const { if(!data_->getArgument(15) || data_->getArgument(15)->isNull()) { return boost::none; } double v = *data_->getArgument(15); return v; }
-void Ifc4x3_rc4::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(15,attr);} }
+void Ifc4x3_rc4::IfcWindowLiningProperties::setLiningToPanelOffsetY(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(15,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcWindowLiningProperties::declaration() const { return *IFC4X3_RC4_IfcWindowLiningProperties_type; }
@@ -23424,9 +23424,9 @@ void Ifc4x3_rc4::IfcWindowPanelProperties::setOperationType(::Ifc4x3_rc4::IfcWin
 ::Ifc4x3_rc4::IfcWindowPanelPositionEnum::Value Ifc4x3_rc4::IfcWindowPanelProperties::PanelPosition() const {  return ::Ifc4x3_rc4::IfcWindowPanelPositionEnum::FromString(*data_->getArgument(5)); }
 void Ifc4x3_rc4::IfcWindowPanelProperties::setPanelPosition(::Ifc4x3_rc4::IfcWindowPanelPositionEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcWindowPanelPositionEnum::ToString(v)));data_->setArgument(5,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowPanelProperties::FrameDepth() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } double v = *data_->getArgument(6); return v; }
-void Ifc4x3_rc4::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcWindowPanelProperties::setFrameDepth(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcWindowPanelProperties::FrameThickness() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcWindowPanelProperties::setFrameThickness(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 ::Ifc4x3_rc4::IfcShapeAspect* Ifc4x3_rc4::IfcWindowPanelProperties::ShapeAspectStyle() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(8)))->as<::Ifc4x3_rc4::IfcShapeAspect>(true); }
 void Ifc4x3_rc4::IfcWindowPanelProperties::setShapeAspectStyle(::Ifc4x3_rc4::IfcShapeAspect* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(8,attr);} }
 
@@ -23466,9 +23466,9 @@ void Ifc4x3_rc4::IfcWindowType::setPredefinedType(::Ifc4x3_rc4::IfcWindowTypeEnu
 ::Ifc4x3_rc4::IfcWindowTypePartitioningEnum::Value Ifc4x3_rc4::IfcWindowType::PartitioningType() const {  return ::Ifc4x3_rc4::IfcWindowTypePartitioningEnum::FromString(*data_->getArgument(10)); }
 void Ifc4x3_rc4::IfcWindowType::setPartitioningType(::Ifc4x3_rc4::IfcWindowTypePartitioningEnum::Value v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(v,::Ifc4x3_rc4::IfcWindowTypePartitioningEnum::ToString(v)));data_->setArgument(10,attr);} }
 boost::optional< bool > Ifc4x3_rc4::IfcWindowType::ParameterTakesPrecedence() const { if(!data_->getArgument(11) || data_->getArgument(11)->isNull()) { return boost::none; } bool v = *data_->getArgument(11); return v; }
-void Ifc4x3_rc4::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(11,attr);} }
+void Ifc4x3_rc4::IfcWindowType::setParameterTakesPrecedence(boost::optional< bool > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcWindowType::UserDefinedPartitioningType() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcWindowType::setUserDefinedPartitioningType(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcWindowType::declaration() const { return *IFC4X3_RC4_IfcWindowType_type; }
@@ -23478,11 +23478,11 @@ Ifc4x3_rc4::IfcWindowType::IfcWindowType(std::string v1_GlobalId, ::Ifc4x3_rc4::
 
 // Function implementations for IfcWorkCalendar
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcWorkTime >::ptr > Ifc4x3_rc4::IfcWorkCalendar::WorkingTimes() const { if(!data_->getArgument(6) || data_->getArgument(6)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(6); return es->as< ::Ifc4x3_rc4::IfcWorkTime >(); }
-void Ifc4x3_rc4::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(6,attr);} }
+void Ifc4x3_rc4::IfcWorkCalendar::setWorkingTimes(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcWorkTime >::ptr > Ifc4x3_rc4::IfcWorkCalendar::ExceptionTimes() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc4::IfcWorkTime >(); }
-void Ifc4x3_rc4::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcWorkCalendar::setExceptionTimes(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcWorkTime >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< ::Ifc4x3_rc4::IfcWorkCalendarTypeEnum::Value > Ifc4x3_rc4::IfcWorkCalendar::PredefinedType() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcWorkCalendarTypeEnum::FromString(*data_->getArgument(8)); }
-void Ifc4x3_rc4::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWorkCalendarTypeEnum::ToString(*v)));data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcWorkCalendar::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWorkCalendarTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWorkCalendarTypeEnum::ToString(*v)));}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcWorkCalendar::declaration() const { return *IFC4X3_RC4_IfcWorkCalendar_type; }
@@ -23494,17 +23494,17 @@ Ifc4x3_rc4::IfcWorkCalendar::IfcWorkCalendar(std::string v1_GlobalId, ::Ifc4x3_r
 std::string Ifc4x3_rc4::IfcWorkControl::CreationDate() const {  std::string v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcWorkControl::setCreationDate(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPerson >::ptr > Ifc4x3_rc4::IfcWorkControl::Creators() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } aggregate_of_instance::ptr es = *data_->getArgument(7); return es->as< ::Ifc4x3_rc4::IfcPerson >(); }
-void Ifc4x3_rc4::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set((*v)->generalize());data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcWorkControl::setCreators(boost::optional< aggregate_of< ::Ifc4x3_rc4::IfcPerson >::ptr > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set((*v)->generalize());}data_->setArgument(7,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcWorkControl::Purpose() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } std::string v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcWorkControl::setPurpose(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcWorkControl::Duration() const { if(!data_->getArgument(9) || data_->getArgument(9)->isNull()) { return boost::none; } std::string v = *data_->getArgument(9); return v; }
-void Ifc4x3_rc4::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(9,attr);} }
+void Ifc4x3_rc4::IfcWorkControl::setDuration(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(9,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcWorkControl::TotalFloat() const { if(!data_->getArgument(10) || data_->getArgument(10)->isNull()) { return boost::none; } std::string v = *data_->getArgument(10); return v; }
-void Ifc4x3_rc4::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(10,attr);} }
+void Ifc4x3_rc4::IfcWorkControl::setTotalFloat(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(10,attr);} }
 std::string Ifc4x3_rc4::IfcWorkControl::StartTime() const {  std::string v = *data_->getArgument(11); return v; }
 void Ifc4x3_rc4::IfcWorkControl::setStartTime(std::string v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(11,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcWorkControl::FinishTime() const { if(!data_->getArgument(12) || data_->getArgument(12)->isNull()) { return boost::none; } std::string v = *data_->getArgument(12); return v; }
-void Ifc4x3_rc4::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(12,attr);} }
+void Ifc4x3_rc4::IfcWorkControl::setFinishTime(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(12,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcWorkControl::declaration() const { return *IFC4X3_RC4_IfcWorkControl_type; }
@@ -23514,7 +23514,7 @@ Ifc4x3_rc4::IfcWorkControl::IfcWorkControl(std::string v1_GlobalId, ::Ifc4x3_rc4
 
 // Function implementations for IfcWorkPlan
 boost::optional< ::Ifc4x3_rc4::IfcWorkPlanTypeEnum::Value > Ifc4x3_rc4::IfcWorkPlan::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcWorkPlanTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc4::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWorkPlanTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcWorkPlan::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWorkPlanTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWorkPlanTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcWorkPlan::declaration() const { return *IFC4X3_RC4_IfcWorkPlan_type; }
@@ -23524,7 +23524,7 @@ Ifc4x3_rc4::IfcWorkPlan::IfcWorkPlan(std::string v1_GlobalId, ::Ifc4x3_rc4::IfcO
 
 // Function implementations for IfcWorkSchedule
 boost::optional< ::Ifc4x3_rc4::IfcWorkScheduleTypeEnum::Value > Ifc4x3_rc4::IfcWorkSchedule::PredefinedType() const { if(!data_->getArgument(13) || data_->getArgument(13)->isNull()) { return boost::none; } return ::Ifc4x3_rc4::IfcWorkScheduleTypeEnum::FromString(*data_->getArgument(13)); }
-void Ifc4x3_rc4::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWorkScheduleTypeEnum::ToString(*v)));data_->setArgument(13,attr);} }
+void Ifc4x3_rc4::IfcWorkSchedule::setPredefinedType(boost::optional< ::Ifc4x3_rc4::IfcWorkScheduleTypeEnum::Value > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(IfcWrite::IfcWriteArgument::EnumerationReference(*v,::Ifc4x3_rc4::IfcWorkScheduleTypeEnum::ToString(*v)));}data_->setArgument(13,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcWorkSchedule::declaration() const { return *IFC4X3_RC4_IfcWorkSchedule_type; }
@@ -23536,9 +23536,9 @@ Ifc4x3_rc4::IfcWorkSchedule::IfcWorkSchedule(std::string v1_GlobalId, ::Ifc4x3_r
 ::Ifc4x3_rc4::IfcRecurrencePattern* Ifc4x3_rc4::IfcWorkTime::RecurrencePattern() const { if(!data_->getArgument(3) || data_->getArgument(3)->isNull()) { return nullptr; } return ((IfcUtil::IfcBaseClass*)(*data_->getArgument(3)))->as<::Ifc4x3_rc4::IfcRecurrencePattern>(true); }
 void Ifc4x3_rc4::IfcWorkTime::setRecurrencePattern(::Ifc4x3_rc4::IfcRecurrencePattern* v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(3,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcWorkTime::Start() const { if(!data_->getArgument(4) || data_->getArgument(4)->isNull()) { return boost::none; } std::string v = *data_->getArgument(4); return v; }
-void Ifc4x3_rc4::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(4,attr);} }
+void Ifc4x3_rc4::IfcWorkTime::setStart(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(4,attr);} }
 boost::optional< std::string > Ifc4x3_rc4::IfcWorkTime::Finish() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcWorkTime::setFinish(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcWorkTime::declaration() const { return *IFC4X3_RC4_IfcWorkTime_type; }
@@ -23556,9 +23556,9 @@ void Ifc4x3_rc4::IfcZShapeProfileDef::setWebThickness(double v) { {IfcWrite::Ifc
 double Ifc4x3_rc4::IfcZShapeProfileDef::FlangeThickness() const {  double v = *data_->getArgument(6); return v; }
 void Ifc4x3_rc4::IfcZShapeProfileDef::setFlangeThickness(double v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(v);data_->setArgument(6,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcZShapeProfileDef::FilletRadius() const { if(!data_->getArgument(7) || data_->getArgument(7)->isNull()) { return boost::none; } double v = *data_->getArgument(7); return v; }
-void Ifc4x3_rc4::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(7,attr);} }
+void Ifc4x3_rc4::IfcZShapeProfileDef::setFilletRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(7,attr);} }
 boost::optional< double > Ifc4x3_rc4::IfcZShapeProfileDef::EdgeRadius() const { if(!data_->getArgument(8) || data_->getArgument(8)->isNull()) { return boost::none; } double v = *data_->getArgument(8); return v; }
-void Ifc4x3_rc4::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(8,attr);} }
+void Ifc4x3_rc4::IfcZShapeProfileDef::setEdgeRadius(boost::optional< double > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(8,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcZShapeProfileDef::declaration() const { return *IFC4X3_RC4_IfcZShapeProfileDef_type; }
@@ -23568,7 +23568,7 @@ Ifc4x3_rc4::IfcZShapeProfileDef::IfcZShapeProfileDef(::Ifc4x3_rc4::IfcProfileTyp
 
 // Function implementations for IfcZone
 boost::optional< std::string > Ifc4x3_rc4::IfcZone::LongName() const { if(!data_->getArgument(5) || data_->getArgument(5)->isNull()) { return boost::none; } std::string v = *data_->getArgument(5); return v; }
-void Ifc4x3_rc4::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();attr->set(*v);data_->setArgument(5,attr);} }
+void Ifc4x3_rc4::IfcZone::setLongName(boost::optional< std::string > v) { {IfcWrite::IfcWriteArgument* attr = new IfcWrite::IfcWriteArgument();if (v) {attr->set(*v);}data_->setArgument(5,attr);} }
 
 
 const IfcParse::entity& Ifc4x3_rc4::IfcZone::declaration() const { return *IFC4X3_RC4_IfcZone_type; }