It *can* return null, too.

Author: andris-sevcenko

src/base/Gateway.php

@@ -463,9 +463,9 @@ abstract protected function createGateway(): AbstractGateway;
      *
      * @param Order $order The order.
      *
-     * @return ItemBag
+     * @return ItemBag|null
      */
-    protected function createItemBagForOrder(Order $order): ItemBag
+    protected function createItemBagForOrder(Order $order)
     {
         if (!$this->sendCartInfo) {
             return null;