ConversationMessageModel::instance PHP Метод

    public static function instance()
    {
        if (!isset(self::$instance)) {
            self::$instance = new ConversationMessageModel();
        }
        return self::$instance;
    }

 /**
  * Return the singleton instance of this class.
  */
 public static function instance()
 {
     if (!isset(self::$instance)) {
         self::$instance = new ConversationMessageModel();
     }
     return self::$instance;
 }