public static function GetBaseCurrency()
    {
        static $oInstance = null;
        if (null === $oInstance) {
            $oInstance = TdbPkgShopCurrency::GetNewInstance();
            if (false === $oInstance->LoadFromField('is_base_currency', '1')) {
                $oInstance = false;
            }
        }

        return $oInstance;
    }