code: func (f *int32Flag) Set(s string) error {
  	i, err := strconv.ParseInt(s, 10, 32)
  	if err != nil {
  		return errors.Reason("values must be 32-bit integers").Err()
  	}
  	*f = int32Flag(i)
  	return nil
  }
docs: // Set records seeing a flag value.