public function getBasketHash($sAmazonOrderReferenceId, $oBasket)
    {
        $aBasket = array(
            'amazonOrderReferenceId' => $sAmazonOrderReferenceId,
            'totalSum' => $oBasket->getBruttoSum(),
            'contents' => array()
        );

        /** @var oxBasketItem $oBasketItem */
        foreach ($oBasket->getContents() as $oBasketItem) {
            $sId = $oBasketItem->getArticle()->getId();
            $aBasket['contents'][$sId] = $oBasketItem->getAmount();
        }

        return md5(json_encode($aBasket));
    }