protected function getShopParentClass()
    {
        $className = get_class($this); //actual class, might be shop class chain extended by module
        while ($className && !\OxidEsales\Eshop\Core\NamespaceInformationProvider::classBelongsToShopUnifiedNamespace($className)) {
            $className = get_parent_class($className);
        }
        return $className;
    }