private function getStockId($websiteId)
    {
        if (!isset($this->stockIdByWebsite[$websiteId])) {
            $stockId = $this->stockRegistry->getStock($websiteId)->getStockId();
            $this->stockIdByWebsite[$websiteId] = $stockId;
        }

        return $this->stockIdByWebsite[$websiteId];
    }