public function getProductNumber()
    {
        /** @var $this OxpsPaymorrowOxBasketItem|oxBasketItem */

        /** @var oxArticle $oArticle */
        $oArticle = $this->getArticle();

        return isset( $oArticle->oxarticles__oxartnum->value ) ? (string) $oArticle->oxarticles__oxartnum->value : '';
    }