code: func (s *AuthService) DeleteSubscription(c context.Context, subscription string) error {
  	var reply struct {
  		Error struct {
  			Code int `json:"code"`
  		} `json:"error"`
  	}
  	req := internal.Request{
  		Method: "DELETE",
  		URL:    s.pubSubURL(subscription),
  		Scopes: oauthScopes,
  		Out:    &reply,
  	}
  	if err := req.Do(c); err != nil && reply.Error.Code != 404 {
  		return err
  	}
  	return nil
  }
docs: // DeleteSubscription removes PubSub subscription if it exists.