code: func handleNotifyDarwin(r *Request) (interface{}, error) {
  	args := r.Args.MustSliceOfLength(3)
  	cmd := exec.Command("osascript", "-e", fmt.Sprintf("display notification \"%s\" with title \"%s\" subtitle \"%s\"",
  		args[1].MustString(), args[2].MustString(), args[0].MustString()))
  	return nil, cmd.Start()
  }
docs: // handleNotifyDarwin displays a desktop notification on OS X.