code: def _update_dict(self, to_dict, from_dict):
          
          for key, value in from_dict.items():
              if key in to_dict and isinstance(to_dict[key], dict) and \
                      isinstance(from_dict[key], dict):
                  self._update_dict(to_dict[key], from_dict[key])
              else:
                  to_dict[key] = from_dict[key]
docs: Recursively merges the fields for two dictionaries.
  
          Args:
              to_dict (dict): The dictionary onto which the merge is executed.
              from_dict (dict): The dictionary merged into to_dict