code: func rateLimitExceeded(err *googleapi.Error) bool {
  	for _, err := range err.Errors {
  		if strings.Contains(err.Message, "Rate Limit Exceeded") {
  			return true
  		}
  	}
  	return false
  }
docs: // rateLimitExceeded returns whether the given *googleapi.Error contains a rate
  // limit error.