public function getPCStorage()
    {
        if (isset($this->pclasses)) {
            return $this->pclasses;
        }

        include_once 'pclasses/storage.intf.php';
        $className = $this->pcStorage.'storage';
        $pclassStorage = dirname(__FILE__) . "/pclasses/{$className}.class.php";

        include_once $pclassStorage;
        $storage = new $className;

        if (!($storage instanceof PCStorage)) {
            throw new Klarna_PCStorageInvalidException(
                $className, $pclassStorage
            );
        }
        return $storage;
    }