remove_representation - small optimizations

check schema version instead of accessing attribute directly (hasattr under the hood is just doing getattr and checking whether it returns AttributeError), so one less IFC access

Similar thing with element.Item to access IFC just once.

src/ifcopenshell-python/ifcopenshell/api/geometry/remove_representation.py

@@ -37,6 +37,7 @@ def remove_representation(
     :param should_keep_named_profiles: If true, named profile defs will not be
         removed as they are assumed to be significant.
     """
+    is_ifc2x3 = file.schema == "IFC2X3"
     styled_items = set()
     presentation_layer_assignments = set()
     textures = set()
@@ -46,9 +47,7 @@ def remove_representation(
         if subelement.is_a("IfcRepresentationItem"):
             [styled_items.add(s) for s in subelement.StyledByItem or []]
             # IFC2X3 is using LayerAssignments
-            for s in (
-                subelement.LayerAssignment if hasattr(subelement, "LayerAssignment") else subelement.LayerAssignments
-            ):
+            for s in subelement.LayerAssignment if not is_ifc2x3 else subelement.LayerAssignments:
                 presentation_layer_assignments.add(s)
             # IfcTessellatedFaceSet inverses
             [textures.add(t) for t in getattr(subelement, "HasTextures", []) or []]
@@ -77,7 +76,8 @@ def remove_representation(
 
     to_delete = file.to_delete or set()
     for element in styled_items:
-        if not element.Item or element.Item in to_delete:
+        item = element.Item
+        if not item or item in to_delete:
             file.remove(element)
     for element in presentation_layer_assignments:
         if all(item in to_delete for item in element.AssignedItems):