code: def handle_error(
          self,
          error: ValidationError,
          req: Request,
          schema: Schema,
          error_status_code: typing.Union[int, None] = None,
          error_headers: typing.Union[typing.Mapping[str, str], None] = None,
      ) -> "typing.NoReturn":
          
          error_class = exception_map.get(
              error_status_code or self.DEFAULT_VALIDATION_STATUS
          )
          if not error_class:
              raise LookupError("No exception for {0}".format(error_status_code))
          headers = error_headers
          raise error_class(
              body=json.dumps(error.messages).encode("utf-8"),
              headers=headers,
              content_type="application/json",
          )
docs: Handle ValidationErrors and return a JSON response of error messages
          to the client.