code: def handle_error(self, error, req, schema, error_status_code, error_headers):
          
          status_code = error_status_code or self.DEFAULT_VALIDATION_STATUS
          if status_code == 422:
              reason = "Unprocessable Entity"
          else:
              reason = None
          raise HTTPError(
              status_code,
              log_message=str(error.messages),
              reason=reason,
              messages=error.messages,
              headers=error_headers,
          )
docs: Handles errors during parsing. Raises a `tornado.web.HTTPError`
          with a 400 error.