code: func (md *MobileDetect) Is(key interface{}) bool {
  	switch key.(type) {
  	case string:
  		name := strings.ToLower(key.(string))
  		ruleKey, ok := md.rules.nameToKey(name)
  		if !ok {
  			return false
  		}
  		return md.matchUAAgainstKey(ruleKey)
  	case int:
  		ruleKey := key.(int)
  		return md.IsKey(ruleKey)
  	}
  	return false
  }
docs: // It is recommended to use IsKey instead