docs: def _parse_response_types(argspec, attrs):
          """
          from the given parameters, return back the response type dictionaries.
          """
          return_type = argspec.annotations.get("return") or None
          type_description = attrs.parameter_descriptions.get("return", "")
          response_types = attrs.response_types.copy()
          if return_type or len(response_types) == 0:
              response_types[attrs.success_code] = ResponseType(
                  type=return_type,
                  type_description=type_description,
                  description="success",
              )
          return response_types