code: func (d *Flags) Parse() error {
  	if !d.Verbose {
  		log.SetFlags(0)
  		log.SetOutput(ioutil.Discard)
  	}
  	if d.Quiet && d.Verbose {
  		return errors.New("can't use both -quiet and -verbose")
  	}
  	if d.TracePath != "" {
  		p, err := filepath.Abs(d.TracePath)
  		if err != nil {
  			return err
  		}
  		d.TracePath = p
  	}
  	return nil
  }
docs: // Parse applies changes specified by command line flags.