diff --git a/src/ifcopenshell-python/ifcopenshell/api/attribute/edit_attributes.py b/src/ifcopenshell-python/ifcopenshell/api/attribute/edit_attributes.py
index 05dbff5a5c..650c2c57bd 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/attribute/edit_attributes.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/attribute/edit_attributes.py
@@ -17,9 +17,11 @@
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
 import ifcopenshell.api
+import ifcopenshell.util.element
+from typing import Any
 
 
-def edit_attributes(file, product=None, attributes=None) -> None:
+def edit_attributes(file: ifcopenshell.file, product: ifcopenshell.entity_instance, attributes: dict[str, Any]) -> None:
     """Edit the attributes of a product
 
     All IFC entities have attributes. Normally they can be edited directly,
@@ -31,7 +33,7 @@ def edit_attributes(file, product=None, attributes=None) -> None:
         entity.
     :type product: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/boundary/assign_connection_geometry.py b/src/ifcopenshell-python/ifcopenshell/api/boundary/assign_connection_geometry.py
index b184810642..90994d8499 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/boundary/assign_connection_geometry.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/boundary/assign_connection_geometry.py
@@ -17,17 +17,18 @@
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
 import ifcopenshell.util.unit
+from typing import Optional
 
 
 def assign_connection_geometry(
-    file,
-    rel_space_boundary=None,
-    outer_boundary=None,
-    inner_boundaries=None,
-    location=None,
-    axis=None,
-    ref_direction=None,
-    unit_scale=None,
+    file: ifcopenshell.file,
+    rel_space_boundary: ifcopenshell.entity_instance,
+    outer_boundary: list[tuple[float, float]],
+    location: tuple[float, float, float],
+    axis: tuple[float, float, float],
+    ref_direction: tuple[float, float, float],
+    inner_boundaries: Optional[list[list[tuple[float, float]]]] = None,
+    unit_scale: Optional[float] = None,
 ) -> None:
     """Create and assign a connection geometry to a space boundary relationship
 
@@ -44,24 +45,24 @@ def assign_connection_geometry(
         polyline.  The last point will connect to the first point. Each
         point is represented by an interable of 2 floats. The coordinates of
         the points are relative to the positional matrix arguments.
-    :type outer_boundary: list[list[float]]
+    :type outer_boundary: list[tuple[float, float]]
     :param inner_boundaries: A list of zero or more inner boundaries to use
         for the plane. Each boundary is represented by an open polyline, as
         defined by the outer_boundary argument.
-    :type inner_boundaries: list[list[list[float]]], optional
+    :type inner_boundaries: list[list[tuple[float, float]]], optional
     :param location: The local origin of the connection geometry, defined as
         an XYZ coordinate relative to the placement of the space that is
         being bounded.
-    :type location: list[float]
+    :type location: tuple[float, float, float]
     :param axis: The local X axis of the connection geometry, defined as an
         XYZ vector relative to the placement of the space that is being
         bounded.
-    :type axis: list[float]
+    :type axis: tuple[float, float, float]
     :param ref_direction: The local Z axis of the connection geometry,
         defined as an XYZ vector relative to the placement of the space that
         is being bounded. The Y vector is automatically derived using the
         right hand rule.
-    :type ref_direction: list[float]
+    :type ref_direction: tuple[float, float, float]
     :param unit_scale: The unit scale as calculated by
         ifcopenshell.util.unit.calculate_unit_scale. If not provided, it
         will be automatically calculated for you.
diff --git a/src/ifcopenshell-python/ifcopenshell/api/boundary/copy_boundary.py b/src/ifcopenshell-python/ifcopenshell/api/boundary/copy_boundary.py
index b051bae828..791cc09bbb 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/boundary/copy_boundary.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/boundary/copy_boundary.py
@@ -19,13 +19,13 @@
 import ifcopenshell.util.element
 
 
-def copy_boundary(file, boundary=None) -> None:
+def copy_boundary(file: ifcopenshell.file, boundary: ifcopenshell.entity_instance) -> ifcopenshell.entity_instance:
     """Copies a space boundary
 
     :param boundary: The IfcRelSpaceBoundary you want to copy.
     :type boundary: ifcopenshell.entity_instance
-    :return: None
-    :rtype: None
+    :return: Duplicate of the IfcRelSpaceBoundary
+    :rtype: ifcopenshell.entity_instance
 
     Example:
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/boundary/edit_attributes.py b/src/ifcopenshell-python/ifcopenshell/api/boundary/edit_attributes.py
index 663c656dbb..449d16c12a 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/boundary/edit_attributes.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/boundary/edit_attributes.py
@@ -15,15 +15,17 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Optional
 
 
 def edit_attributes(
-    file,
-    entity=None,
-    relating_space=None,
-    related_building_element=None,
-    parent_boundary=None,
-    corresponding_boundary=None,
+    file: ifcopenshell.file,
+    entity: ifcopenshell.entity_instance,
+    relating_space: ifcopenshell.entity_instance,
+    related_building_element: ifcopenshell.entity_instance,
+    parent_boundary: Optional[ifcopenshell.entity_instance] = None,
+    corresponding_boundary: Optional[ifcopenshell.entity_instance] = None,
 ) -> None:
     """Modify the relationships of a space boundary relationship
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/boundary/remove_boundary.py b/src/ifcopenshell-python/ifcopenshell/api/boundary/remove_boundary.py
index dadf44e3c7..6962a3121a 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/boundary/remove_boundary.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/boundary/remove_boundary.py
@@ -20,7 +20,7 @@ import ifcopenshell
 import ifcopenshell.util.element
 
 
-def remove_boundary(file, boundary=None) -> None:
+def remove_boundary(file: ifcopenshell.file, boundary: ifcopenshell.entity_instance) -> None:
     """Removes a space boundary
 
     The relating space or related building element is untouched. Only the
diff --git a/src/ifcopenshell-python/ifcopenshell/api/classification/edit_classification.py b/src/ifcopenshell-python/ifcopenshell/api/classification/edit_classification.py
index 7568a11d5e..f7577bdc4c 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/classification/edit_classification.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/classification/edit_classification.py
@@ -15,9 +15,13 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_classification(file, classification=None, attributes=None) -> None:
+def edit_classification(
+    file: ifcopenshell.file, classification: ifcopenshell.entity_instance, attributes: dict[str, Any]
+) -> None:
     """Edits the attributes of an IfcClassification
 
     For more information about the attributes and data types of an
@@ -26,7 +30,7 @@ def edit_classification(file, classification=None, attributes=None) -> None:
     :param classification: The IfcClassification entity you want to edit
     :type classification: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/classification/edit_reference.py b/src/ifcopenshell-python/ifcopenshell/api/classification/edit_reference.py
index dc5096f38c..d8052a333f 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/classification/edit_reference.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/classification/edit_reference.py
@@ -15,9 +15,13 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_reference(file, reference=None, attributes=None) -> None:
+def edit_reference(
+    file: ifcopenshell.file, reference: ifcopenshell.entity_instance, attributes: dict[str, Any]
+) -> None:
     """Edits the attributes of an IfcClassificationReference
 
     For more information about the attributes and data types of an
@@ -26,7 +30,7 @@ def edit_reference(file, reference=None, attributes=None) -> None:
     :param reference: The IfcClassificationReference entity you want to edit
     :type reference: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/classification/remove_classification.py b/src/ifcopenshell-python/ifcopenshell/api/classification/remove_classification.py
index 21e02d7b86..38ae9408e6 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/classification/remove_classification.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/classification/remove_classification.py
@@ -20,7 +20,7 @@ import ifcopenshell
 import ifcopenshell.util.element
 
 
-def remove_classification(file: ifcopenshell.entity_instance, classification: ifcopenshell.entity_instance) -> None:
+def remove_classification(file: ifcopenshell.file, classification: ifcopenshell.entity_instance) -> None:
     """Removes an IfcClassification from the project and all references
 
     The classification and all of its relationships, children references,
diff --git a/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric.py b/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric.py
index ab0870b528..70ca67a743 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric.py
@@ -19,7 +19,7 @@
 import ifcopenshell
 
 
-def add_metric(file, objective=None) -> None:
+def add_metric(file: ifcopenshell.file, objective: ifcopenshell.entity_instance) -> ifcopenshell.entity_instance:
     """Add a new metric benchmark
 
     Qualitative constraints may have a series of quantitative benchmarks
@@ -50,7 +50,7 @@ def add_metric(file, objective=None) -> None:
             "Name": "Unnamed",
             "ConstraintGrade": "NOTDEFINED",
             "Benchmark": "EQUALTO",
-        }
+        },
     )
     if settings["objective"]:
         benchmark_values = list(settings["objective"].BenchmarkValues or [])
diff --git a/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric_reference.py b/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric_reference.py
index a3c37392e2..fdcdf50f6f 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric_reference.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/constraint/add_metric_reference.py
@@ -19,16 +19,18 @@
 import ifcopenshell
 
 
-def add_metric_reference(file, metric=None, reference_path=None) -> None:
+def add_metric_reference(
+    file: ifcopenshell.file, metric: ifcopenshell.entity_instance, reference_path: str
+) -> list[ifcopenshell.entity_instance]:
     """
     Adds a chain of references to a metric. The reference path is a string of the form "attribute.attribute.attribute"
     Used to reference a value of an attribute of an instance through a metric objective entity.
     """
     settings = {"metric": metric, "reference_path": reference_path}
 
+    references_created = []
     if settings["reference_path"]:
         attributes = settings["reference_path"].split(".")
-        references_created = []
         for i in range(len(attributes)):
             if i == 0:
                 reference = file.create_entity("IfcReference")
@@ -40,4 +42,4 @@ def add_metric_reference(file, metric=None, reference_path=None) -> None:
                 reference.AttributeIdentifier = attributes[i]
                 references_created[i - 1].InnerReference = reference
                 references_created.append(reference)
-        return references_created
+    return references_created
diff --git a/src/ifcopenshell-python/ifcopenshell/api/constraint/add_objective.py b/src/ifcopenshell-python/ifcopenshell/api/constraint/add_objective.py
index efce0bc080..2d8c0ab8db 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/constraint/add_objective.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/constraint/add_objective.py
@@ -19,7 +19,7 @@
 import ifcopenshell
 
 
-def add_objective(file) -> None:
+def add_objective(file: ifcopenshell.file) -> ifcopenshell.entity_instance:
     """Add a new objective constraint
 
     Parametric constraints may be defined by the user. The constraint is defined
diff --git a/src/ifcopenshell-python/ifcopenshell/api/constraint/edit_metric.py b/src/ifcopenshell-python/ifcopenshell/api/constraint/edit_metric.py
index b1ba5699ca..f90d1590d9 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/constraint/edit_metric.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/constraint/edit_metric.py
@@ -15,9 +15,11 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_metric(file, metric=None, attributes=None) -> None:
+def edit_metric(file: ifcopenshell.file, metric: ifcopenshell.entity_instance, attributes: dict[str, Any]) -> None:
     """Edit the attributes of a metric
 
     For more information about the attributes and data types of an
@@ -26,7 +28,7 @@ def edit_metric(file, metric=None, attributes=None) -> None:
     :param metric: The IfcMetric you want to edit.
     :type metric: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/constraint/edit_objective.py b/src/ifcopenshell-python/ifcopenshell/api/constraint/edit_objective.py
index 6ce5c597e8..0004261031 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/constraint/edit_objective.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/constraint/edit_objective.py
@@ -15,9 +15,13 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_objective(file, objective=None, attributes=None) -> None:
+def edit_objective(
+    file: ifcopenshell.file, objective: ifcopenshell.entity_instance, attributes: dict[str, Any]
+) -> None:
     """Edit the attributes of a objective
 
     For more information about the attributes and data types of an
@@ -26,7 +30,7 @@ def edit_objective(file, objective=None, attributes=None) -> None:
     :param objective: The IfcObjective you want to edit.
     :type objective: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/constraint/remove_constraint.py b/src/ifcopenshell-python/ifcopenshell/api/constraint/remove_constraint.py
index 30b61fb5c7..aea342e126 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/constraint/remove_constraint.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/constraint/remove_constraint.py
@@ -20,7 +20,7 @@ import ifcopenshell
 import ifcopenshell.util.element
 
 
-def remove_constraint(file, constraint=None) -> None:
+def remove_constraint(file: ifcopenshell.file, constraint: ifcopenshell.entity_instance) -> None:
     """Remove a constraint (typically an objective)
 
     Removes a constraint definition and all of its associations to any
diff --git a/src/ifcopenshell-python/ifcopenshell/api/constraint/remove_metric.py b/src/ifcopenshell-python/ifcopenshell/api/constraint/remove_metric.py
index 49203da3c5..2829a3355f 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/constraint/remove_metric.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/constraint/remove_metric.py
@@ -15,9 +15,10 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
 
 
-def remove_metric(file, metric=None) -> None:
+def remove_metric(file: ifcopenshell.file, metric: ifcopenshell.entity_instance) -> None:
     """Remove a metric benchmark
 
     Removes a metric benchmark and all of its associations to any products
diff --git a/src/ifcopenshell-python/ifcopenshell/api/context/remove_context.py b/src/ifcopenshell-python/ifcopenshell/api/context/remove_context.py
index 94547b675e..e80cbddaf6 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/context/remove_context.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/context/remove_context.py
@@ -17,9 +17,11 @@
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
 import ifcopenshell
+import ifcopenshell.api
+import ifcopenshell.util.element
 
 
-def remove_context(file: ifcopenshell.entity_instance, context: ifcopenshell.entity_instance) -> None:
+def remove_context(file: ifcopenshell.file, context: ifcopenshell.entity_instance) -> None:
     """Removes an IfcGeometricRepresentationContext
 
     Any representation geometry that is assigned to the context is also
diff --git a/src/ifcopenshell-python/ifcopenshell/api/control/assign_control.py b/src/ifcopenshell-python/ifcopenshell/api/control/assign_control.py
index ed52f1be73..b9ca8ab9d0 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/control/assign_control.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/control/assign_control.py
@@ -19,9 +19,14 @@
 import ifcopenshell
 import ifcopenshell.api
 import ifcopenshell.guid
+from typing import Union
 
 
-def assign_control(file, relating_control=None, related_object=None) -> None:
+def assign_control(
+    file: ifcopenshell.file,
+    relating_control: ifcopenshell.entity_instance,
+    related_object: ifcopenshell.entity_instance,
+) -> Union[ifcopenshell.entity_instance, None]:
     """Assigns a planning control or constraint to an object
 
     IFC can describe concepts that control other objects. For example, a
diff --git a/src/ifcopenshell-python/ifcopenshell/api/control/unassign_control.py b/src/ifcopenshell-python/ifcopenshell/api/control/unassign_control.py
index 0463689c5f..f2d4cc8a9b 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/control/unassign_control.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/control/unassign_control.py
@@ -19,9 +19,14 @@
 import ifcopenshell
 import ifcopenshell.api
 import ifcopenshell.util.element
+from typing import Union
 
 
-def unassign_control(file, relating_control=None, related_object=None) -> None:
+def unassign_control(
+    file: ifcopenshell.file,
+    relating_control: ifcopenshell.entity_instance,
+    related_object: ifcopenshell.entity_instance,
+) -> Union[ifcopenshell.entity_instance, None]:
     """Unassigns a planning control or constraint to an object
 
     :param relating_control: The IfcControl entity that is creating the
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item.py b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item.py
index 461279942a..a33c17c890 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item.py
@@ -18,22 +18,29 @@
 
 import ifcopenshell.api
 import ifcopenshell.guid
+from typing import Optional
 
 
-def add_cost_item(file, cost_schedule=None, cost_item=None) -> None:
+def add_cost_item(
+    file: ifcopenshell.file,
+    cost_schedule: Optional[ifcopenshell.entity_instance] = None,
+    cost_item: Optional[ifcopenshell.entity_instance] = None,
+) -> ifcopenshell.entity_instance:
     """Add a new cost item
 
     A cost item represents a single line item in a cost schedule. Cost items
     may then be broken down into cost subitems.
 
+    Either `cost_schedule` or `cost_item` must be provided.
+
     :param cost_schedule: If the cost item is to be added as a root or top
         level cost item to a cost schedule, the IfcCostSchedule may be
         specified. This is mutually exlclusive to the cost_item parameter.
-    :type cost_schedule: ifcopenshell.entity_instance
+    :type cost_schedule: ifcopenshell.entity_instance, optional.
     :param cost_item: If the cost item is to be added as a subitem to an
         existing cost item, the parent IfcCostItem may be specified. This is
         mutually exclusive to the cost_schedule parameter.
-    :type cost_item: ifcopenshell.entity_instance
+    :type cost_item: ifcopenshell.entity_instance, optional
     :return: The newly created IfcCostItem
     :rtype: ifcopenshell.entity_instance
 
@@ -62,7 +69,7 @@ def add_cost_item(file, cost_schedule=None, cost_item=None) -> None:
                 "OwnerHistory": ifcopenshell.api.run("owner.create_owner_history", file),
                 "RelatedObjects": [cost_item],
                 "RelatingControl": settings["cost_schedule"],
-            }
+            },
         )
     elif settings["cost_item"]:
         ifcopenshell.api.run(
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item_quantity.py b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item_quantity.py
index 47a9b3efb9..61ba86f6b2 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item_quantity.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item_quantity.py
@@ -19,7 +19,9 @@
 import ifcopenshell.api
 
 
-def add_cost_item_quantity(file, cost_item=None, ifc_class="IfcQuantityCount") -> None:
+def add_cost_item_quantity(
+    file: ifcopenshell.file, cost_item: ifcopenshell.entity_instance, ifc_class: str = "IfcQuantityCount"
+) -> ifcopenshell.entity_instance:
     """Adds a new quantity associated with a cost item
 
     Cost items calculate their subtotal by multiplying the sum of the cost
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_schedule.py b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_schedule.py
index d72566ae1f..95c638182a 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_schedule.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_schedule.py
@@ -19,9 +19,10 @@
 import ifcopenshell.api
 import ifcopenshell.util.date
 from datetime import datetime
+from typing import Optional
 
 
-def add_cost_schedule(file, name=None, predefined_type="NOTDEFINED") -> None:
+def add_cost_schedule(file: ifcopenshell.file, name: Optional[str] = None, predefined_type="NOTDEFINED") -> None:
     """Add a new cost schedule
 
     A cost schedule is a group of cost items which typically represent a
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_value.py b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_value.py
index b6fe5f5698..6c59af0bb6 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_value.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_value.py
@@ -15,9 +15,10 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
 
 
-def add_cost_value(file, parent=None) -> None:
+def add_cost_value(file: ifcopenshell.file, parent: ifcopenshell.entity_instance) -> ifcopenshell.entity_instance:
     """Adds a new value or subvalue to a cost item
 
     A cost item's subtotal can be specified in two ways.
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py b/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py
index 6c13162ed7..bf5b412a21 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py
@@ -17,9 +17,15 @@
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
 import ifcopenshell.api
+from typing import Optional
 
 
-def assign_cost_item_quantity(file, cost_item=None, products=None, prop_name="") -> None:
+def assign_cost_item_quantity(
+    file: ifcopenshell.file,
+    cost_item: ifcopenshell.entity_instance,
+    products: list[ifcopenshell.entity_instance],
+    prop_name: Optional[str] = "",
+) -> None:
     """Adds a cost item quantity that is parametrically connected to a product
 
     A cost item may have its subtotal calculated by multiplying a unit value
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_value.py b/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_value.py
index 18bb05694f..dda9d509eb 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_value.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_value.py
@@ -19,7 +19,9 @@
 import ifcopenshell.api
 
 
-def assign_cost_value(file, cost_item=None, cost_rate=None) -> None:
+def assign_cost_value(
+    file: ifcopenshell.file, cost_item: ifcopenshell.entity_instance, cost_rate: ifcopenshell.entity_instance
+) -> None:
     """Assigns a cost value to a cost item from a schedule of rates
 
     Instead of assigning cost values from scratch for each cost item in a
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/calculate_cost_item_resource_value.py b/src/ifcopenshell-python/ifcopenshell/api/cost/calculate_cost_item_resource_value.py
index c977be1b19..897a2d7412 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/calculate_cost_item_resource_value.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/calculate_cost_item_resource_value.py
@@ -21,7 +21,7 @@ import ifcopenshell.util.date
 import ifcopenshell.util.resource
 
 
-def calculate_cost_item_resource_value(file, cost_item=None) -> None:
+def calculate_cost_item_resource_value(file: ifcopenshell.file, cost_item: ifcopenshell.entity_instance) -> None:
     """Calculates the total cost of all resources associated with a cost item
 
     A cost item may have construction resources (e.g. equipment, material,
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/copy_cost_item.py b/src/ifcopenshell-python/ifcopenshell/api/cost/copy_cost_item.py
index 13927088ed..7b08df16a5 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/copy_cost_item.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/copy_cost_item.py
@@ -19,9 +19,14 @@
 import ifcopenshell
 import ifcopenshell.api
 import ifcopenshell.util.element
+from typing import Union
 
 
-def copy_cost_item(file, cost_item=None) -> None:
+def copy_cost_item(
+    file: ifcopenshell.file, cost_item: ifcopenshell.entity_instance
+) -> Union[ifcopenshell.entity_instance, list[ifcopenshell.entity_instance]]:
+    # TODO: currently it never returns list of duplicated cost items
+    # though it is stated in the docs
     """Copies all cost items and related relationships
 
     The following relationships are also duplicated:
@@ -33,7 +38,7 @@ def copy_cost_item(file, cost_item=None) -> None:
     :param cost_item: The cost item to be duplicated
     :type cost_item: ifcopenshell.entity_instance
     :return: The duplicated cost item or the list of duplicated cost items if the latter has children
-    :rtype: ifcopenshell.entity_instance or list of ifcopenshell.entity_instance
+    :rtype: ifcopenshell.entity_instance or list[ifcopenshell.entity_instance]
 
     Example:
     .. code:: python
@@ -55,7 +60,7 @@ def copy_cost_item(file, cost_item=None) -> None:
 class Usecase:
     def execute(self):
         self.new_cost_items = []
-        self.duplicate_cost_item(self.settings["cost_item"])
+        return self.duplicate_cost_item(self.settings["cost_item"])
 
     def duplicate_cost_item(self, cost_item):
         new_cost_item = ifcopenshell.util.element.copy_deep(self.file, cost_item)
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/copy_cost_item_values.py b/src/ifcopenshell-python/ifcopenshell/api/cost/copy_cost_item_values.py
index 8ccb0a4158..6fadb9a349 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/copy_cost_item_values.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/copy_cost_item_values.py
@@ -20,7 +20,9 @@ import ifcopenshell.util.element
 import ifcopenshell.api
 
 
-def copy_cost_item_values(file, source=None, destination=None) -> None:
+def copy_cost_item_values(
+    file: ifcopenshell.file, source: ifcopenshell.entity_instance, destination: ifcopenshell.entity_instance
+) -> None:
     """Copies all cost values from one cost item to another
 
     Any previously existing values will be removed. The entire value is
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_item.py b/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_item.py
index 2bf72a5d57..4d168173b6 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_item.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_item.py
@@ -15,9 +15,13 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_cost_item(file, cost_item=None, attributes=None) -> None:
+def edit_cost_item(
+    file: ifcopenshell.file, cost_item: ifcopenshell.entity_instance, attributes: dict[str, Any]
+) -> None:
     """Edits the attributes of an IfcCostItem
 
     For more information about the attributes and data types of an
@@ -26,7 +30,7 @@ def edit_cost_item(file, cost_item=None, attributes=None) -> None:
     :param cost_item: The IfcCostItem entity you want to edit
     :type cost_item: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_item_quantity.py b/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_item_quantity.py
index 178816a593..9d1c7a554c 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_item_quantity.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_item_quantity.py
@@ -15,9 +15,13 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_cost_item_quantity(file, physical_quantity=None, attributes=None) -> None:
+def edit_cost_item_quantity(
+    file: ifcopenshell.file, physical_quantity: ifcopenshell.entity_instance, attributes: dict[str, Any]
+) -> None:
     """Edits the attributes of an IfcPhysicalQuantity
 
     For more information about the attributes and data types of an
@@ -26,7 +30,7 @@ def edit_cost_item_quantity(file, physical_quantity=None, attributes=None) -> No
     :param physical_quantity: The IfcPhysicalQuantity entity you want to edit
     :type physical_quantity: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_schedule.py b/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_schedule.py
index 3e47f3a430..f7392951f6 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_schedule.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_schedule.py
@@ -15,9 +15,13 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_cost_schedule(file, cost_schedule=None, attributes=None) -> None:
+def edit_cost_schedule(
+    file: ifcopenshell.file, cost_schedule: ifcopenshell.entity_instance, attributes: dict[str, Any]
+) -> None:
     """Edits the attributes of an IfcCostSchedule
 
     For more information about the attributes and data types of an
@@ -26,7 +30,7 @@ def edit_cost_schedule(file, cost_schedule=None, attributes=None) -> None:
     :param cost_schedule: The IfcCostSchedule entity you want to edit
     :type cost_schedule: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_value.py b/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_value.py
index 430b4272aa..a0e74b85af 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_value.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_value.py
@@ -19,9 +19,12 @@
 import ifcopenshell
 import ifcopenshell.util.unit
 import ifcopenshell.util.element
+from typing import Any
 
 
-def edit_cost_value(file, cost_value=None, attributes=None) -> None:
+def edit_cost_value(
+    file: ifcopenshell.file, cost_value: ifcopenshell.entity_instance, attributes: dict[str, Any]
+) -> None:
     """Edits the attributes of an IfcCostValue
 
     For more information about the attributes and data types of an
@@ -30,7 +33,7 @@ def edit_cost_value(file, cost_value=None, attributes=None) -> None:
     :param cost_value: The IfcCostValue entity you want to edit
     :type cost_value: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_value_formula.py b/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_value_formula.py
index eac443ba40..a9af7572b6 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_value_formula.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/edit_cost_value_formula.py
@@ -22,7 +22,7 @@ import ifcopenshell.util.unit
 import ifcopenshell.util.element
 
 
-def edit_cost_value_formula(file, cost_value=None, formula=None) -> None:
+def edit_cost_value_formula(file: ifcopenshell.file, cost_value: ifcopenshell.entity_instance, formula: str) -> None:
     """Sets a cost value based on a formula, similar to formulas in spreadsheets
 
     Costs may be made up of many components (e.g. labour, material, waste
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_item.py b/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_item.py
index e52fd655cb..119b22d135 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_item.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_item.py
@@ -21,7 +21,7 @@ import ifcopenshell.api
 import ifcopenshell.util.element
 
 
-def remove_cost_item(file, cost_item=None) -> None:
+def remove_cost_item(file: ifcopenshell.file, cost_item: ifcopenshell.entity_instance) -> None:
     """Removes a cost item
 
     All associated relationships with the cost item are also removed,
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_item_quantity.py b/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_item_quantity.py
index eed3a7adb3..cc7b8c32cb 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_item_quantity.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_item_quantity.py
@@ -15,9 +15,12 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
 
 
-def remove_cost_item_quantity(file, cost_item=None, physical_quantity=None) -> None:
+def remove_cost_item_quantity(
+    file: ifcopenshell.file, cost_item: ifcopenshell.entity_instance, physical_quantity: ifcopenshell.entity_instance
+) -> None:
     """Removes a quantity assigned to a cost item
 
     If the quantity is part of a product (e.g. wall), then the quantity will
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_schedule.py b/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_schedule.py
index 7b73859bb0..01a9c0e0ad 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_schedule.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_schedule.py
@@ -21,7 +21,7 @@ import ifcopenshell.api
 import ifcopenshell.util.element
 
 
-def remove_cost_schedule(file, cost_schedule=None) -> None:
+def remove_cost_schedule(file: ifcopenshell.file, cost_schedule: ifcopenshell.entity_instance) -> None:
     """Removes a cost schedule
 
     All associated relationships with the cost schedule are also removed,
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_value.py b/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_value.py
index 757877bf9d..10f4054e93 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_value.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/remove_cost_value.py
@@ -15,9 +15,12 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
 
 
-def remove_cost_value(file, parent=None, cost_value=None) -> None:
+def remove_cost_value(
+    file: ifcopenshell.file, parent: ifcopenshell.entity_instance, cost_value: ifcopenshell.entity_instance
+) -> None:
     """Removes a cost value
 
     The cost value may be assigned either to a cost item, a construction
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/unassign_cost_item_quantity.py b/src/ifcopenshell-python/ifcopenshell/api/cost/unassign_cost_item_quantity.py
index c7c5fc69fd..a11947c6d8 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/unassign_cost_item_quantity.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/unassign_cost_item_quantity.py
@@ -19,7 +19,9 @@
 import ifcopenshell.api
 
 
-def unassign_cost_item_quantity(file, cost_item=None, products=None) -> None:
+def unassign_cost_item_quantity(
+    file: ifcopenshell.file, cost_item: ifcopenshell.entity_instance, products: list[ifcopenshell.entity_instance]
+) -> None:
     """Removes quantities of a cost item that are calculated on products
 
     A cost item may have quantities that are parametrically calculated on
diff --git a/src/ifcopenshell-python/ifcopenshell/api/document/add_information.py b/src/ifcopenshell-python/ifcopenshell/api/document/add_information.py
index 7754f8cef5..86db04421c 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/document/add_information.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/document/add_information.py
@@ -18,9 +18,12 @@
 
 import ifcopenshell
 import ifcopenshell.guid
+from typing import Optional
 
 
-def add_information(file, parent=None) -> None:
+def add_information(
+    file: ifcopenshell.file, parent: Optional[ifcopenshell.entity_instance] = None
+) -> ifcopenshell.entity_instance:
     """Adds a new document information to the project
 
     An IFC document information is a document associated with the project.
diff --git a/src/ifcopenshell-python/ifcopenshell/api/drawing/assign_product.py b/src/ifcopenshell-python/ifcopenshell/api/drawing/assign_product.py
index c0758c8145..e620724727 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/drawing/assign_product.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/drawing/assign_product.py
@@ -21,7 +21,11 @@ import ifcopenshell.api
 import ifcopenshell.guid
 
 
-def assign_product(file, relating_product=None, related_object=None) -> None:
+def assign_product(
+    file: ifcopenshell.file,
+    relating_product: ifcopenshell.entity_instance,
+    related_object: ifcopenshell.entity_instance,
+) -> ifcopenshell.entity_instance:
     """Associates a product and an object, typically for annotation
 
     Warning: this is an experimental API.
@@ -104,7 +108,7 @@ def assign_product(file, relating_product=None, related_object=None) -> None:
                 "OwnerHistory": ifcopenshell.api.run("owner.create_owner_history", file),
                 "RelatedObjects": [settings["related_object"]],
                 "RelatingProduct": settings["relating_product"],
-            }
+            },
         )
 
     if is_grid_axis:
diff --git a/src/ifcopenshell-python/ifcopenshell/api/drawing/edit_text_literal.py b/src/ifcopenshell-python/ifcopenshell/api/drawing/edit_text_literal.py
index f1aadc25b0..73ba58a776 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/drawing/edit_text_literal.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/drawing/edit_text_literal.py
@@ -15,9 +15,13 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_text_literal(file, text_literal=None, attributes=None) -> None:
+def edit_text_literal(
+    file: ifcopenshell.file, text_literal: ifcopenshell.entity_instance, attributes: dict[str, Any]
+) -> None:
     """Edits the attributes of an IfcTextLiteral
 
     For more information about the attributes and data types of an
@@ -26,7 +30,7 @@ def edit_text_literal(file, text_literal=None, attributes=None) -> None:
     :param reference: The IfcTextLiteral entity you want to edit
     :type reference: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/drawing/unassign_product.py b/src/ifcopenshell-python/ifcopenshell/api/drawing/unassign_product.py
index 8254bffdce..b0f6ad1085 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/drawing/unassign_product.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/drawing/unassign_product.py
@@ -21,7 +21,11 @@ import ifcopenshell.api
 import ifcopenshell.util.element
 
 
-def unassign_product(file, relating_product=None, related_object=None) -> None:
+def unassign_product(
+    file: ifcopenshell.file,
+    relating_product: ifcopenshell.entity_instance,
+    related_object: ifcopenshell.entity_instance,
+) -> None:
     """Unassigns a product and an object (typically an annotation)
 
     Smart annotation objects can be associated with products so that they
@@ -34,8 +38,8 @@ def unassign_product(file, relating_product=None, related_object=None) -> None:
     :param related_object: The object (typically IfcAnnotation) that the
         product is related to
     :type related_object: ifcopenshell.entity_instance
-    :return: The created IfcRelAssignsToProduct relationship
-    :rtype: ifcopenshell.entity_instance
+    :return: None
+    :rtype: None
 
     Example:
 
@@ -68,4 +72,3 @@ def unassign_product(file, relating_product=None, related_object=None) -> None:
         related_objects.remove(settings["related_object"])
         rel.RelatedObjects = related_objects
         ifcopenshell.api.run("owner.update_owner_history", file, **{"element": rel})
-        return rel
diff --git a/src/ifcopenshell-python/ifcopenshell/api/owner/add_person.py b/src/ifcopenshell-python/ifcopenshell/api/owner/add_person.py
index 5d571920d4..7abdfb1598 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/owner/add_person.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/owner/add_person.py
@@ -19,7 +19,7 @@ import ifcopenshell
 
 
 def add_person(
-    file: ifcopenshell.entity_instance,
+    file: ifcopenshell.file,
     identification: str = "HSeldon",
     family_name: str = "Seldon",
     given_name: str = "Hari",
diff --git a/src/ifcopenshell-python/ifcopenshell/api/owner/add_person_and_organisation.py b/src/ifcopenshell-python/ifcopenshell/api/owner/add_person_and_organisation.py
index 7f07c1991c..cf2bdb6507 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/owner/add_person_and_organisation.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/owner/add_person_and_organisation.py
@@ -19,7 +19,7 @@ import ifcopenshell
 
 
 def add_person_and_organisation(
-    file: ifcopenshell.entity_instance,
+    file: ifcopenshell.file,
     person: ifcopenshell.entity_instance,
     organisation: ifcopenshell.entity_instance,
 ) -> ifcopenshell.entity_instance:
diff --git a/src/ifcopenshell-python/ifcopenshell/api/owner/create_owner_history.py b/src/ifcopenshell-python/ifcopenshell/api/owner/create_owner_history.py
index 2b4729897f..fbb35dbc45 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/owner/create_owner_history.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/owner/create_owner_history.py
@@ -22,7 +22,7 @@ import ifcopenshell.api.owner.settings
 from typing import Union
 
 
-def create_owner_history(file: ifcopenshell.entity_instance) -> Union[ifcopenshell.entity_instance, None]:
+def create_owner_history(file: ifcopenshell.file) -> Union[ifcopenshell.entity_instance, None]:
     """Creates a new owner history indicating an element was added
 
     Any object in IFC with a unique ID and name (such as physical products,
diff --git a/src/ifcopenshell-python/ifcopenshell/api/project/assign_declaration.py b/src/ifcopenshell-python/ifcopenshell/api/project/assign_declaration.py
index 322e8a18ad..bffef52943 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/project/assign_declaration.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/project/assign_declaration.py
@@ -24,7 +24,7 @@ from typing import Union
 
 
 def assign_declaration(
-    file: ifcopenshell.entity_instance,
+    file: ifcopenshell.file,
     definitions: list[ifcopenshell.entity_instance],
     relating_context: ifcopenshell.entity_instance,
 ) -> Union[ifcopenshell.entity_instance, None]:
@@ -142,6 +142,6 @@ def assign_declaration(
                 "OwnerHistory": ifcopenshell.api.run("owner.create_owner_history", file),
                 "RelatedDefinitions": list(objects_to_change),
                 "RelatingContext": relating_context,
-            }
+            },
         )
     return declares
diff --git a/src/ifcopenshell-python/ifcopenshell/api/pset/edit_pset.py b/src/ifcopenshell-python/ifcopenshell/api/pset/edit_pset.py
index 01d5d9b2ea..288adebab5 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/pset/edit_pset.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/pset/edit_pset.py
@@ -22,7 +22,7 @@ from typing import Optional, Any, Union
 
 
 def edit_pset(
-    file: ifcopenshell.entity_instance,
+    file: ifcopenshell.file,
     pset: ifcopenshell.entity_instance,
     name: Optional[str] = None,
     properties: Optional[dict[str, Any]] = None,
diff --git a/src/ifcopenshell-python/ifcopenshell/api/unit/add_context_dependent_unit.py b/src/ifcopenshell-python/ifcopenshell/api/unit/add_context_dependent_unit.py
index 5de43a505a..ee37c32f53 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/unit/add_context_dependent_unit.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/unit/add_context_dependent_unit.py
@@ -15,9 +15,15 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
 
 
-def add_context_dependent_unit(file, unit_type="USERDEFINED", name="THINGAMAJIG", dimensions=None) -> None:
+def add_context_dependent_unit(
+    file: ifcopenshell.file,
+    unit_type: str = "USERDEFINED",
+    name: str = "THINGAMAJIG",
+    dimensions: tuple[int, int, int, int, int, int, int] = (0, 0, 0, 0, 0, 0, 0),
+) -> ifcopenshell.entity_instance:
     """Add a new arbitrary unit that can only be interpreted in a project specific context
 
     Occasionally the construction industry uses arbitrary units to quantify
@@ -51,7 +57,7 @@ def add_context_dependent_unit(file, unit_type="USERDEFINED", name="THINGAMAJIG"
         # Boxes of things
         ifcopenshell.api.run("unit.add_context_dependent_unit", model, name="BOXES")
     """
-    settings = {"unit_type": unit_type, "name": name, "dimensions": dimensions or (0, 0, 0, 0, 0, 0, 0)}
+    settings = {"unit_type": unit_type, "name": name, "dimensions": dimensions}
 
     return file.create_entity(
         "IfcContextDependentUnit",
diff --git a/src/ifcopenshell-python/ifcopenshell/api/unit/add_monetary_unit.py b/src/ifcopenshell-python/ifcopenshell/api/unit/add_monetary_unit.py
index 7e345b9a7c..4cf9ca6730 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/unit/add_monetary_unit.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/unit/add_monetary_unit.py
@@ -15,9 +15,10 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
 
 
-def add_monetary_unit(file, currency="DOLLARYDOO") -> None:
+def add_monetary_unit(file: ifcopenshell.file, currency: str = "DOLLARYDOO") -> ifcopenshell.entity_instance:
     """Add a new currency
 
     Currency units are useful in cost plans to know in what currency the
diff --git a/src/ifcopenshell-python/ifcopenshell/api/unit/edit_derived_unit.py b/src/ifcopenshell-python/ifcopenshell/api/unit/edit_derived_unit.py
index ed56b80461..a8b3316dbd 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/unit/edit_derived_unit.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/unit/edit_derived_unit.py
@@ -15,9 +15,11 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_derived_unit(file, unit=None, attributes=None) -> None:
+def edit_derived_unit(file: ifcopenshell.file, unit: ifcopenshell.entity_instance, attributes: dict[str, Any]) -> None:
     """Edits the attributes of an IfcDerivedUnit
 
     For more information about the attributes and data types of an
@@ -26,7 +28,7 @@ def edit_derived_unit(file, unit=None, attributes=None) -> None:
     :param unit: The IfcDerivedUnit entity you want to edit
     :type unit: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
     """
diff --git a/src/ifcopenshell-python/ifcopenshell/api/unit/edit_monetary_unit.py b/src/ifcopenshell-python/ifcopenshell/api/unit/edit_monetary_unit.py
index b4f14f328a..888bbde510 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/unit/edit_monetary_unit.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/unit/edit_monetary_unit.py
@@ -15,9 +15,11 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_monetary_unit(file, unit=None, attributes=None) -> None:
+def edit_monetary_unit(file: ifcopenshell.file, unit: ifcopenshell.entity_instance, attributes: dict[str, Any]) -> None:
     """Edits the attributes of an IfcMonetaryUnit
 
     For more information about the attributes and data types of an
@@ -26,7 +28,7 @@ def edit_monetary_unit(file, unit=None, attributes=None) -> None:
     :param unit: The IfcMonetaryUnit entity you want to edit
     :type unit: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/unit/edit_named_unit.py b/src/ifcopenshell-python/ifcopenshell/api/unit/edit_named_unit.py
index be0384aabb..72cd618839 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/unit/edit_named_unit.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/unit/edit_named_unit.py
@@ -15,9 +15,11 @@
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+import ifcopenshell
+from typing import Any
 
 
-def edit_named_unit(file, unit=None, attributes=None) -> None:
+def edit_named_unit(file: ifcopenshell.file, unit: ifcopenshell.entity_instance, attributes: dict[str, Any]) -> None:
     """Edits the attributes of an IfcNamedUnit
 
     Named units include SI units, conversion based units (imperial units),
@@ -29,7 +31,7 @@ def edit_named_unit(file, unit=None, attributes=None) -> None:
     :param unit: The IfcNamedUnit entity you want to edit
     :type unit: ifcopenshell.entity_instance
     :param attributes: a dictionary of attribute names and values.
-    :type attributes: dict, optional
+    :type attributes: dict
     :return: None
     :rtype: None
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/unit/remove_unit.py b/src/ifcopenshell-python/ifcopenshell/api/unit/remove_unit.py
index ae2cd192cb..eb572aa59c 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/unit/remove_unit.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/unit/remove_unit.py
@@ -20,7 +20,7 @@ import ifcopenshell.util.unit
 import ifcopenshell.util.element
 
 
-def remove_unit(file, unit=None) -> None:
+def remove_unit(file: ifcopenshell.file, unit: ifcopenshell.entity_instance) -> None:
     """Remove a unit
 
     Be very careful when a unit is removed, as it may mean that previously
diff --git a/src/ifcopenshell-python/ifcopenshell/api/void/add_filling.py b/src/ifcopenshell-python/ifcopenshell/api/void/add_filling.py
index 9e8d09744d..bdc0422955 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/void/add_filling.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/void/add_filling.py
@@ -21,7 +21,9 @@ import ifcopenshell.guid
 import ifcopenshell.util.element
 
 
-def add_filling(file, opening=None, element=None) -> None:
+def add_filling(
+    file: ifcopenshell.file, opening: ifcopenshell.entity_instance, element: ifcopenshell.entity_instance
+) -> ifcopenshell.entity_instance:
     """Fill an opening with an element
 
     Physical elements may have openings in them. For example, a wall might
@@ -106,13 +108,13 @@ def add_filling(file, opening=None, element=None) -> None:
 
     if fills_voids:
         if fills_voids[0].RelatingOpeningElement == settings["opening"]:
-            return
+            return fills_voids[0]
         history = fills_voids[0].OwnerHistory
         file.remove(fills_voids[0])
         if history:
             ifcopenshell.util.element.remove_deep2(file, history)
 
-    file.create_entity(
+    return file.create_entity(
         "IfcRelFillsElement",
         GlobalId=ifcopenshell.guid.new(),
         RelatingOpeningElement=settings["opening"],
diff --git a/src/ifcopenshell-python/ifcopenshell/api/void/remove_filling.py b/src/ifcopenshell-python/ifcopenshell/api/void/remove_filling.py
index b4c3188672..3cfdd05ce3 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/void/remove_filling.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/void/remove_filling.py
@@ -20,7 +20,7 @@ import ifcopenshell
 import ifcopenshell.util.element
 
 
-def remove_filling(file, element=None) -> None:
+def remove_filling(file: ifcopenshell.file, element: ifcopenshell.entity_instance) -> None:
     """Remove a filling relationship
 
     If an element is filling an opening, this removes the relationship such
diff --git a/src/ifcopenshell-python/ifcopenshell/api/void/remove_opening.py b/src/ifcopenshell-python/ifcopenshell/api/void/remove_opening.py
index 58b7782333..7217fc627d 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/void/remove_opening.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/void/remove_opening.py
@@ -20,7 +20,7 @@ import ifcopenshell.api
 import ifcopenshell.util.element
 
 
-def remove_opening(file: ifcopenshell.entity_instance, opening: ifcopenshell.entity_instance) -> None:
+def remove_opening(file: ifcopenshell.file, opening: ifcopenshell.entity_instance) -> None:
     """Remove an opening
 
     Fillings are retained as orphans. Voided elements remain. Openings
diff --git a/src/ifcopenshell-python/ifcopenshell/entity_instance.py b/src/ifcopenshell-python/ifcopenshell/entity_instance.py
index 05ad3fd984..499c1a260e 100644
--- a/src/ifcopenshell-python/ifcopenshell/entity_instance.py
+++ b/src/ifcopenshell-python/ifcopenshell/entity_instance.py
@@ -281,11 +281,11 @@ class entity_instance:
 
         return entity_instance.walk(is_instance, unwrap, v)
 
-    def attribute_type(self, attr: int) -> str:
+    def attribute_type(self, attr: Union[int, str]) -> str:
         """Return the data type of a positional attribute of the element
 
-        :param attr: The index of the attribute
-        :type attr: int
+        :param attr: The index or name of the attribute
+        :type attr: Union[int, str]
         :rtype: string
         """
         attr_idx = attr if isinstance(attr, numbers.Integral) else self.wrapped_data.get_argument_index(attr)
diff --git a/src/ifcopenshell-python/ifcopenshell/util/placement.py b/src/ifcopenshell-python/ifcopenshell/util/placement.py
index 75a1de6265..f8b52b274c 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/placement.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/placement.py
@@ -19,7 +19,7 @@
 import numpy as np
 import numpy.typing as npt
 import ifcopenshell
-from typing import Literal, Iterable
+from typing import Literal, Iterable, Optional
 
 
 MatrixType = npt.NDArray[np.float64]
@@ -97,7 +97,7 @@ def get_axis2placement(placement: ifcopenshell.entity_instance) -> MatrixType:
     return a2p(o, z, x)
 
 
-def get_local_placement(placement: ifcopenshell.entity_instance) -> MatrixType:
+def get_local_placement(placement: Optional[ifcopenshell.entity_instance] = None) -> MatrixType:
     """Parse a local placement into a 4x4 transformation matrix
 
     This is typically used to find the location and rotation of an element. The
@@ -118,7 +118,7 @@ def get_local_placement(placement: ifcopenshell.entity_instance) -> MatrixType:
         matrix = ifcopenshell.util.placement.get_local_placement(placement)
 
     :param placement: The IfcLocalPlacement entity
-    :type placement: ifcopenshell.entity_instance
+    :type placement: ifcopenshell.entity_instance, optional
     :return: A 4x4 numpy matrix
     :rtype: MatrixType
     """