diff --git a/src/bonsai/bonsai/bim/import_ifc.py b/src/bonsai/bonsai/bim/import_ifc.py
index 5fde08e638..35c4b12dfa 100644
--- a/src/bonsai/bonsai/bim/import_ifc.py
+++ b/src/bonsai/bonsai/bim/import_ifc.py
@@ -40,29 +40,33 @@ from typing import Dict, Union, Optional, Any
 
 
 class MaterialCreator:
+    mesh: bpy.types.Mesh
+    obj: bpy.types.Object
+
     def __init__(self, ifc_import_settings: IfcImportSettings, ifc_importer: IfcImporter):
-        self.mesh: bpy.types.Mesh = None
-        self.obj: bpy.types.Object = None
         self.styles: Dict[int, bpy.types.Material] = {}
         self.parsed_meshes: set[str] = set()
         self.ifc_import_settings = ifc_import_settings
         self.ifc_importer = ifc_importer
 
-    def create(self, element: ifcopenshell.entity_instance, obj: bpy.types.Object, mesh: OBJECT_DATA_TYPE) -> None:
-        self.mesh = mesh
-        # as ifcopenshell triangulates the mesh, we need to merge it to quads again
-        self.obj = obj
-        if (hasattr(element, "Representation") and not element.Representation) or (
-            hasattr(element, "RepresentationMaps") and not element.RepresentationMaps
+    def create(
+        self, element: ifcopenshell.entity_instance, obj: bpy.types.Object, mesh: Union[OBJECT_DATA_TYPE, None]
+    ) -> None:
+        if ((rep := getattr(element, "Representation", ...) is not ...) and not rep) or (
+            (rep := getattr(element, "RepresentationMaps", ...) is not ...) and not rep
         ):
             return
-        if not self.mesh or self.mesh.name in self.parsed_meshes:
+
+        if not mesh or mesh.name in self.parsed_meshes:
             return
 
         # We don't support curve styles yet.
         if isinstance(mesh, bpy.types.Curve):
             return
 
+        self.mesh = mesh
+        self.obj = obj
+
         # mesh["ios_materials"] can contain:
         # - ifc style id if style assigned to the representation items directly
         # or through material with a style;
diff --git a/src/ifcopenshell-python/ifcopenshell/api/material/copy_material.py b/src/ifcopenshell-python/ifcopenshell/api/material/copy_material.py
index b98490ef07..d250ac742b 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/material/copy_material.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/material/copy_material.py
@@ -33,9 +33,7 @@ def copy_material(file: ifcopenshell.file, material: ifcopenshell.entity_instanc
     style is reused.
 
     :param material: The IfcMaterialDefinition to copy
-    :type material: ifcopenshell.entity_instance
     :return: The new copy of the material
-    :rtype: ifcopenshell.entity_instance
 
     Example:
 
@@ -68,9 +66,13 @@ def copy_material(file: ifcopenshell.file, material: ifcopenshell.entity_instanc
         return _copy_material_with_inverses(file, material)
     elif material.is_a("IfcMaterialList"):
         return _copy_material_with_inverses(file, material)
+    else:
+        raise Exception(f"Unexpected material type: '{material.is_a()}' ({material}).")
 
 
-def _copy_material_with_inverses(file, material):
+def _copy_material_with_inverses(
+    file: ifcopenshell.file, material: ifcopenshell.entity_instance
+) -> ifcopenshell.entity_instance:
     new = ifcopenshell.util.element.copy(file, material)
     for inverse in file.get_inverse(material):
         if inverse.is_a("IfcMaterialProperties"):
diff --git a/src/ifcopenshell-python/ifcopenshell/api/style/assign_representation_styles.py b/src/ifcopenshell-python/ifcopenshell/api/style/assign_representation_styles.py
index b9b43ee8d0..e1c92995be 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/style/assign_representation_styles.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/style/assign_representation_styles.py
@@ -16,6 +16,7 @@
 # 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 assign_representation_styles(
@@ -112,6 +113,10 @@ def assign_representation_styles(
 
 
 class Usecase:
+    file: ifcopenshell.file
+    settings: dict[str, Any]
+    results: list[ifcopenshell.entity_instance]
+
     def execute(self):
         if not self.settings["styles"]:
             return []
diff --git a/src/ifcopenshell-python/ifcopenshell/util/selector.py b/src/ifcopenshell-python/ifcopenshell/util/selector.py
index 824b7f1864..8497e99a07 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/selector.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/selector.py
@@ -21,7 +21,6 @@ import lark
 import numpy as np
 import ifcopenshell.api.pset
 import ifcopenshell.api.geometry
-import ifcopenshell.ifcopenshell_wrapper as W
 import ifcopenshell.util
 import ifcopenshell.util.attribute
 import ifcopenshell.util.fm
diff --git a/src/ifcopenshell-python/test/api/pset/test_unshare_pset.py b/src/ifcopenshell-python/test/api/pset/test_unshare_pset.py
index b13bd5196e..846d2d5a54 100644
--- a/src/ifcopenshell-python/test/api/pset/test_unshare_pset.py
+++ b/src/ifcopenshell-python/test/api/pset/test_unshare_pset.py
@@ -16,7 +16,6 @@
 # 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 operator
 import test.bootstrap
 import ifcopenshell.api.pset
 import ifcopenshell.api.root