IceCreamShop/IceCreamShopFileImplement/Implements/OrderStorage.cs

@@ -88,6 +88,8 @@ model)
 
         public OrderViewModel AccessIceCreamStorage(OrderViewModel model)
         {
+            if (model == null)
+                return null;
             foreach (var iceCream in source.IceCreams)
             {
                 if (iceCream.Id == model.IceCreamId)