docs: def is_modified(self):
          """
          Returns whether model is modified or not
          """
          if len(self.__modified_data__) or len(self.__deleted_fields__):
              return True
  
          for value in self.__original_data__.values():
              try:
                  if value.is_modified():
                      return True
              except AttributeError:
                  pass
  
          return False