public static async Task Main(string[] args)
        {
            var printer    = new ConsoleReceiptPrinter();
            var calculator = new ReceiptCalculator(new InMemoryItemsRepository(), new TaxCalculator(0.10m, 0.05m));

            foreach (var cart in CreateSampleShoppingCarts())
            {
                var receipt = await calculator.CalculateAsync(cart);

                await printer.PrintAsync(receipt);
            }
        }