code: func SimplifiedLocale(lang string) string {
  	// en_US/en_US.UTF-8/zh_CN/zh_TW/el_GR@euro/...
  	if idx := strings.Index(lang, ":"); idx != -1 {
  		lang = lang[:idx]
  	}
  	if idx := strings.Index(lang, "@"); idx != -1 {
  		lang = lang[:idx]
  	}
  	if idx := strings.Index(lang, "."); idx != -1 {
  		lang = lang[:idx]
  	}
  	return strings.TrimSpace(lang)
  }
docs: // SimplifiedLocale simplified locale like " en_US"/"de_DE "/en_US.UTF-8/zh_CN/zh_TW/el_GR@euro/... to en_US, de_DE, zh_CN, el_GR...