public function getTotalQuantity()
    {
        $iQuantityCount = 0;

        $arOfferList = $this->all();

        /** @var \Lovata\Shopaholic\Classes\Item\OfferItem $arOfferItem */
        foreach ($arOfferList as $arOfferItem) {
            $iQuantityCount += $arOfferItem->quantity;
        }

        return $iQuantityCount;
    }