diff --git a/src/bonsai/bonsai/bim/module/material/operator.py b/src/bonsai/bonsai/bim/module/material/operator.py
index 9d768351d1..bd515252ee 100644
--- a/src/bonsai/bonsai/bim/module/material/operator.py
+++ b/src/bonsai/bonsai/bim/module/material/operator.py
@@ -561,9 +561,12 @@ class EditAssignedMaterial(bpy.types.Operator, tool.Ifc.Operator):
     def _execute(self, context):
         self.file = tool.Ifc.get()
         active_obj = bpy.data.objects.get(self.obj) if self.obj else context.active_object
+        assert active_obj
         props = active_obj.BIMObjectMaterialProperties
         element = tool.Ifc.get_entity(active_obj)
+        assert element
         material = ifcopenshell.util.element.get_material(element)
+        assert material
 
         objects = tool.Blender.get_selected_objects()
 
diff --git a/src/bonsai/bonsai/tool/model.py b/src/bonsai/bonsai/tool/model.py
index 62cabec1b5..c63a9ba466 100644
--- a/src/bonsai/bonsai/tool/model.py
+++ b/src/bonsai/bonsai/tool/model.py
@@ -50,7 +50,7 @@ from bonsai.bim.module.geometry.helper import Helper
 from bonsai.bim.module.model.data import AuthoringData, RailingData, RoofData, WindowData, DoorData
 from bonsai.bim.module.model.opening import FilledOpeningGenerator
 from ifcopenshell.util.shape_builder import ShapeBuilder
-from typing import Optional, Union, TypeVar, Any, Iterable, Literal, TYPE_CHECKING, Sequence
+from typing import Optional, Union, TypeVar, Any, Iterable, Literal, TYPE_CHECKING, Sequence, TypedDict
 
 T = TypeVar("T")
 V_ = tool.Blender.V_
@@ -603,8 +603,16 @@ class Model(bonsai.core.tool.Model):
             if not openings[i].obj:
                 openings.remove(i)
 
+    class MaterialLayerParameters(TypedDict):
+        """Float values are in project units."""
+
+        layer_set_direction: Literal["AXIS1", "AXIS2", "AXIS3"]
+        thickness: float
+        offset: float
+        direction_sense: Literal["NEGATIVE", "POSITIVE"]
+
     @classmethod
-    def get_material_layer_parameters(cls, element: ifcopenshell.entity_instance) -> dict[str, Any]:
+    def get_material_layer_parameters(cls, element: ifcopenshell.entity_instance) -> MaterialLayerParameters:
         unit_scale = ifcopenshell.util.unit.calculate_unit_scale(tool.Ifc.get())
         layer_set_direction = "AXIS2"
         offset = 0.0
@@ -619,12 +627,12 @@ class Model(bonsai.core.tool.Model):
                 material = material.ForLayerSet
             if material.is_a("IfcMaterialLayerSet"):
                 thickness = sum([l.LayerThickness for l in material.MaterialLayers]) * unit_scale
-        return {
-            "layer_set_direction": layer_set_direction,
-            "thickness": thickness,
-            "offset": offset,
-            "direction_sense": direction_sense,
-        }
+        return cls.MaterialLayerParameters(
+            layer_set_direction=layer_set_direction,
+            thickness=thickness,
+            offset=offset,
+            direction_sense=direction_sense,
+        )
 
     @classmethod
     def get_booleans(
@@ -2045,7 +2053,7 @@ class Model(bonsai.core.tool.Model):
         FilledOpeningGenerator().generate(filling_obj, voided_obj)
 
     @classmethod
-    def add_extrusion_position(cls, extrusion: ifcopenshell.entity_instance, position: tuple) -> None:
+    def add_extrusion_position(cls, extrusion: ifcopenshell.entity_instance, position: Vector) -> None:
         ifc_file = tool.Ifc.get()
 
         new_position = ifc_file.createIfcAxis2Placement3D(
diff --git a/src/ifcopenshell-python/ifcopenshell/api/georeference/edit_georeferencing.py b/src/ifcopenshell-python/ifcopenshell/api/georeference/edit_georeferencing.py
index af967e3a79..0d4da93bcb 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/georeference/edit_georeferencing.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/georeference/edit_georeferencing.py
@@ -18,6 +18,7 @@
 
 import ifcopenshell
 import ifcopenshell.api.pset
+import ifcopenshell.util.element
 from typing import Optional, Any
 
 
diff --git a/src/ifcopenshell-python/ifcopenshell/api/root/copy_class.py b/src/ifcopenshell-python/ifcopenshell/api/root/copy_class.py
index 6f02a4531d..56100a403c 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/root/copy_class.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/root/copy_class.py
@@ -54,9 +54,7 @@ def copy_class(file: ifcopenshell.file, product: ifcopenshell.entity_instance) -
       connections are still valid.
 
     :param product: The IfcProduct to copy.
-    :type param: ifcopenshell.entity_instance
     :return: The copied product
-    :rtype: ifcopenshell.entity_instance
 
     Example:
 
@@ -70,26 +68,26 @@ def copy_class(file: ifcopenshell.file, product: ifcopenshell.entity_instance) -
     """
     usecase = Usecase()
     usecase.file = file
-    usecase.settings = {"product": product}
-    return usecase.execute()
+    return usecase.execute(product)
 
 
 class Usecase:
     file: ifcopenshell.file
-    settings: dict[str, Any]
 
-    def execute(self):
-        result = ifcopenshell.util.element.copy(self.file, self.settings["product"])
+    def execute(self, product: ifcopenshell.entity_instance) -> ifcopenshell.entity_instance:
+        result = ifcopenshell.util.element.copy(self.file, product)
         self.copy_direct_attributes(result)
-        self.copy_indirect_attributes(self.settings["product"], result)
+        self.copy_indirect_attributes(product, result)
         return result
 
-    def copy_direct_attributes(self, to_element):
+    def copy_direct_attributes(self, to_element: ifcopenshell.entity_instance) -> None:
         self.remove_representations(to_element)
         self.copy_object_placements(to_element)
         self.copy_psets(to_element)
 
-    def copy_indirect_attributes(self, from_element, to_element):
+    def copy_indirect_attributes(
+        self, from_element: ifcopenshell.entity_instance, to_element: ifcopenshell.entity_instance
+    ) -> None:
         for inverse in self.file.get_inverse(from_element):
             if inverse.is_a("IfcRelDefinesByProperties"):
                 # Properties must not be shared between objects for convenience of authoring
@@ -175,13 +173,13 @@ class Usecase:
                         new_value.append(to_element)
                         inverse[i] = new_value
 
-    def remove_representations(self, element):
+    def remove_representations(self, element: ifcopenshell.entity_instance) -> None:
         if element.is_a("IfcProduct"):
             element.Representation = None
         elif element.is_a("IfcTypeProduct"):
             element.RepresentationMaps = None
 
-    def copy_object_placements(self, element):
+    def copy_object_placements(self, element: ifcopenshell.entity_instance) -> None:
         if not element.is_a("IfcProduct") or not element.ObjectPlacement:
             return
         element.ObjectPlacement = ifcopenshell.util.element.copy(self.file, element.ObjectPlacement)
@@ -189,7 +187,7 @@ class Usecase:
             self.file, element.ObjectPlacement.RelativePlacement
         )
 
-    def copy_psets(self, element):
+    def copy_psets(self, element: ifcopenshell.entity_instance) -> None:
         if not element.is_a("IfcTypeObject") or not element.HasPropertySets:
             return
         element.HasPropertySets = [
diff --git a/src/ifcopenshell-python/ifcopenshell/util/unit.py b/src/ifcopenshell-python/ifcopenshell/util/unit.py
index c28595ae5b..b1862d3882 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/unit.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/unit.py
@@ -20,7 +20,6 @@ from fractions import Fraction
 from math import pi
 from typing import Any
 from typing import Dict
-from typing import Iterable
 from typing import Literal
 from typing import Optional
 from typing import Union
@@ -821,7 +820,8 @@ def iter_element_and_attributes_per_type(ifc_file: ifcopenshell.file, attr_type_
     for element in ifc_file:
         entity = schema.declaration_by_name(element.is_a())
         attrs = entity.all_attributes()
-        for attr, val, is_derived in zip(attrs, list(element), entity.derived()):
+        attrs_derived: tuple[bool, ...] = entity.derived()
+        for attr, val, is_derived in zip(attrs, list(element), attrs_derived):
             if is_derived:
                 continue
 
@@ -877,7 +877,7 @@ def convert_file_length_units(ifc_file: ifcopenshell.file, target_units: str = "
         new_length = ifcopenshell.api.unit.add_conversion_based_unit(file_patched, name=target_units)
 
     # support tuple of tuples, as in IfcCartesianPointList3D.CoordList
-    def convert_value(value):
+    def convert_value(value: FloatOrSequenceOfFloats) -> FloatOrSequenceOfFloats:
         if not isinstance(value, tuple):
             return convert_unit(value, old_length, new_length)
         return tuple(convert_value(v) for v in value)
diff --git a/src/ifcopenshell-python/test/util/test_unit.py b/src/ifcopenshell-python/test/util/test_unit.py
index 98c33397a9..b5f1fc537e 100644
--- a/src/ifcopenshell-python/test/util/test_unit.py
+++ b/src/ifcopenshell-python/test/util/test_unit.py
@@ -18,9 +18,12 @@
 
 import test.bootstrap
 import numpy as np
+import ifcopenshell.api.context
 import ifcopenshell.api.unit
 import ifcopenshell.api.root
 import ifcopenshell.api.georeference
+import ifcopenshell.api.pset
+import ifcopenshell.util.element
 import ifcopenshell.util.geolocation
 import ifcopenshell.util.unit as subject
 from ifcopenshell.util.shape_builder import ShapeBuilder