Mapper::instance PHP Method

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

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