code: func (s *Severity) Set(value string) error {
  	var threshold Severity
  	// Is it a known name?
  	if v, ok := severityByName(value); ok {
  		threshold = v
  	} else {
  		v, err := strconv.Atoi(value)
  		if err != nil {
  			return err
  		}
  		threshold = Severity(v)
  	}
  	*s = threshold
  	return nil
  }
docs: // Set is part of the flag.Value interface.