Miscellany

  public static function singleton() {    if (self::$_instance === null) {      if (isset($_SESSION['shop'])) {        self::$_instance = unserialize($_SESSION['shop']);      } else {        self::$_instance = new shop();        self::$_instance->load();        $_SESSION['shop'] = serialize(self::$_instance);      }    }    self::$_instance->setDefines();    return self::$_instance;  }