code: func GetCompletion(a *cli.App) (string, error) {
  	tplFuncs := template.FuncMap{
  		"formatFlag": formatFlagFunc(),
  	}
  	tpl, err := template.New("zsh").Funcs(tplFuncs).Parse(zshTemplate)
  	if err != nil {
  		return "", err
  	}
  	buf := &bytes.Buffer{}
  	if err := tpl.Execute(buf, a); err != nil {
  		return "", err
  	}
  	return buf.String(), nil
  }
docs: // GetCompletion returns a zsh completion script