public function getCountries()
    {
        if ($this->_aCountries === null) {
            $oDb = \OxidEsales\Eshop\Core\DatabaseProvider::getDb();
            $this->_aCountries = [];
            $sSelect = 'select oxobjectid from oxobject2payment where oxpaymentid=' . $oDb->quote($this->getId()) . ' and oxtype = "oxcountry" ';
            $rs = $oDb->getCol($sSelect);
            $this->_aCountries = $rs;
        }

        return $this->_aCountries;
    }