replace settings=None with {}

src/ifcopenshell-python/ifcopenshell/api/root/copy_class.py

@@ -2,7 +2,7 @@ import ifcopenshell
 
 
 class Usecase:
-    def __init__(self, file, settings=None):
+    def __init__(self, file, settings={}):
         self.file = file
         self.settings = {"product": None}
         for key, value in settings.items():

src/ifcopenshell-python/ifcopenshell/api/root/create_product.py

@@ -3,7 +3,7 @@ from ifcopenshell.api.owner.api import create_owner_history
 
 
 class Usecase:
-    def __init__(self, file, settings=None):
+    def __init__(self, file, settings={}):
         self.file = file
         self.settings = {
             "ifc_class": "IfcBuildingElementProxy",

src/ifcopenshell-python/ifcopenshell/api/root/reassign_class.py

@@ -3,7 +3,7 @@ import ifcopenshell.util.schema
 
 
 class Usecase:
-    def __init__(self, file, settings=None):
+    def __init__(self, file, settings={}):
         self.file = file
         self.settings = {
             "product": None,

src/ifcopenshell-python/ifcopenshell/api/root/remove_product.py

@@ -3,7 +3,7 @@ import ifcopenshell.api.geometry.remove_representation as remove_representation
 
 
 class Usecase:
-    def __init__(self, file, settings=None):
+    def __init__(self, file, settings={}):
         self.file = file
         self.settings = {"product": None}
         for key, value in settings.items():