code: def handle_validation_error(self, error, bundle_errors):
          
          error_str = six.text_type(error)
          error_msg = self.help.format(error_msg=error_str) if self.help else error_str
          msg = {self.name: error_msg}
  
          if current_app.config.get("BUNDLE_ERRORS", False) or bundle_errors:
              return error, msg
          flask_restful.abort(400, message=msg)
docs: Called when an error is raised while parsing. Aborts the request
          with a 400 status and an error message
  
          :param error: the error that was raised
          :param bundle_errors: do not abort when first error occurs, return a
              dict with the name of the argument and the error message to be
              bundled