code: def fail_request(self, orig_request, message, start_response):
      
      cors_handler = self._create_cors_handler(orig_request)
      return util.send_wsgi_error_response(
          message, start_response, cors_handler=cors_handler)
docs: Write an immediate failure response to outfile, no redirect.
  
      This calls start_response and returns the error body.
  
      Args:
        orig_request: An ApiRequest, the original request from the user.
        message: A string containing the error message to be displayed to user.
        start_response: A function with semantics defined in PEP-333.
  
      Returns:
        A string containing the body of the error response.