static void Main(string[] args)
        {
            SunTimes times = new SunTimes(DateTime.Now.AddHours(-2), DateTime.Now.AddHours(8));
            Console.WriteLine("Daylight minutes: " + times.DaylightMinutes());

            ShoppingCart cart = new ShoppingCart();
            cart.AddProduct(1400);
            cart.AddProduct(17);
            cart.Checkout();
        }
        static void Main(string[] args)
        {
            SunTimes times = new SunTimes(DateTime.Now.AddHours(-2), DateTime.Now.AddHours(8));

            Console.WriteLine("Daylight minutes: " + times.DaylightMinutes());

            ShoppingCart cart = new ShoppingCart();

            cart.AddProduct(1400);
            cart.AddProduct(17);
            cart.Checkout();
        }