code: func apiErr(e error) error {
  	err, ok := e.(*googleapi.Error)
  	if !ok {
  		return e
  	}
  	if err.Code == 404 {
  		return config.ErrNoConfig
  	}
  	if err.Code >= 500 {
  		return transient.Tag.Apply(err)
  	}
  	return err
  }
docs: // apiErr converts googleapi.Error to an appropriate type.