diff --git a/cimgen/cimgen.py b/cimgen/cimgen.py
index d12d5a54..13c5efe9 100644
--- a/cimgen/cimgen.py
+++ b/cimgen/cimgen.py
@@ -510,28 +510,43 @@ def _write_python_files(elem_dict, lang_pack, output_path, version):
 
     lang_pack.set_float_classes(float_classes)
     lang_pack.set_enum_classes(enum_classes)
-    lang_pack.set_primitive_classes(primitive_classes)
-    lang_pack.set_cim_data_type_classes(cim_data_type_classes)
+    if "modernpython" in lang_pack.__name__:
+        lang_pack.set_primitive_classes(primitive_classes)
+        lang_pack.set_cim_data_type_classes(cim_data_type_classes)
 
     recommended_class_profiles = _get_recommended_class_profiles(elem_dict)
 
     for class_name in elem_dict.keys():
-
-        class_details = {
-            "attributes": _find_multiple_attributes(elem_dict[class_name].attributes()),
-            "class_location": lang_pack.get_class_location(class_name, elem_dict, output_path),
-            "class_name": class_name,
-            "class_origin": elem_dict[class_name].origins(),
-            "instances": elem_dict[class_name].instances(),
-            "has_instances": elem_dict[class_name].has_instances(),
-            "is_a_float": elem_dict[class_name].is_a_float(),
-            "is_a_primitive": elem_dict[class_name].is_a_primitive(),
-            "is_a_cim_data_type": elem_dict[class_name].is_a_cim_datatype(),
-            "langPack": lang_pack,
-            "sub_class_of": elem_dict[class_name].superClass(),
-            "sub_classes": elem_dict[class_name].subClasses(),
-            "recommended_class_profile": recommended_class_profiles[class_name],
-        }
+        if "modernpython" in lang_pack.__name__:
+            class_details = {
+                "attributes": _find_multiple_attributes(elem_dict[class_name].attributes()),
+                "class_location": lang_pack.get_class_location(class_name, elem_dict, output_path),
+                "class_name": class_name,
+                "class_origin": elem_dict[class_name].origins(),
+                "instances": elem_dict[class_name].instances(),
+                "has_instances": elem_dict[class_name].has_instances(),
+                "is_a_float": elem_dict[class_name].is_a_float(),
+                "is_a_primitive": elem_dict[class_name].is_a_primitive(),
+                "is_a_cim_data_type": elem_dict[class_name].is_a_cim_datatype(),
+                "langPack": lang_pack,
+                "sub_class_of": elem_dict[class_name].superClass(),
+                "sub_classes": elem_dict[class_name].subClasses(),
+                "recommended_class_profile": recommended_class_profiles[class_name],
+            }
+        else:
+            class_details = {
+                "attributes": _find_multiple_attributes(elem_dict[class_name].attributes()),
+                "class_location": lang_pack.get_class_location(class_name, elem_dict, output_path),
+                "class_name": class_name,
+                "class_origin": elem_dict[class_name].origins(),
+                "instances": elem_dict[class_name].instances(),
+                "has_instances": elem_dict[class_name].has_instances(),
+                "is_a_float": elem_dict[class_name].is_a_float(),
+                "langPack": lang_pack,
+                "sub_class_of": elem_dict[class_name].superClass(),
+                "sub_classes": elem_dict[class_name].subClasses(),
+                "recommended_class_profile": recommended_class_profiles[class_name],
+            }
 
         # extract comments
         if elem_dict[class_name].comment: