public bool BindProduct(Guid basketId, ProductModel product, int amount) { var basket = GetBasket(basketId); if (basket == null) { throw new ArgumentNullException("Basket is not found"); } if (amount <= 0) { Console.WriteLine("{0} cannot be added. Product quantity must be greater than 0", product.Title); return(false); } basket.Products.Add(product, amount); basket.SubTotal = BasketHelper.GetSubTotal(basket); basket.DeliveryPrice += CalculateTotalDeliveryPrice(basket); return(true); }