Amend frozen

src/omnipy/data/model.py

@@ -869,8 +869,9 @@ def _parse_with_root_type_if_model(cls,
                 return cast(_RootT,
                             value if is_model_instance(value) else root_type.parse_obj(value))
         if value is None:
-            none_default = root_field.default_factory() is None if root_field.default_factory \
-                else root_field.default is None
+            default_value = root_field.get_default()
+            none_default = default_value is None or (is_model_instance(default_value)
+                                                     and default_value.contents is None)
             root_type_is_none = is_none_type(root_type)
             root_type_is_optional = get_origin(root_type) is Union \
                 and any(is_none_type(arg) for arg in get_args(root_type))

src/omnipy/modules/general/models.py

@@ -31,8 +31,12 @@ class NotIterableExceptStrOrBytesModel(Model[object | None]):
     """
     @classmethod
     def _parse_data(cls, data: object) -> object:
+        if isinstance(data, NotIterableExceptStrOrBytesModel):
+            return data
+
         assert isinstance(data, str) or isinstance(data, bytes) or not is_iterable(data), \
             f'Data of type {type(data)} is iterable'
+
         return data