private static double CalculateDeliveryCost(ShoppingCart shoppingCart) { //TODO: Delivery costs should be dynamic var deliveryCostCalculator = new DeliveryCostCalculator { FixedCost = 2.99, CostPerDelivery = 8, CostPerProduct = 6 }; return(deliveryCostCalculator.CalculateDeliveryCost(shoppingCart)); }