code: func StatusCodeIs(status int) ResponseCondition {
  	return func(res *http.Response) error {
  		if res.StatusCode != status {
  			return fmt.Errorf("got status code %d, wanted %d", res.StatusCode, status)
  		}
  		return nil
  	}
  }
docs: // StatusCodeIs returns a retry condition function.
  // The condition returns an error if the given response's status code is not the
  // given HTTP status code.