}
@Override
public Map<Sku, Integer> retrieveQuantitiesAvailable(Collection<Sku> skus, Map<String, Object> context) {
ExtensionResultHolder<Map<Sku, Integer>> holder = new ExtensionResultHolder<Map<Sku, Integer>>();
ExtensionResultStatusType res = extensionManager.getProxy().retrieveQuantitiesAvailable(skus, context, holder);
if (ExtensionResultStatusType.NOT_HANDLED.equals(res)) {
Map<Sku, Integer> inventories = new HashMap<Sku, Integer>();
for (Sku sku : skus) {
if (checkBasicAvailablility(sku)) {
if (InventoryType.CHECK_QUANTITY.equals(sku.getInventoryType())) {