public static void B_EncapsulationAsHidingOfRealization()
        {
            var deliveryService = new DeliveryService();
            // We do not know, how delivery service works,
            // we give them our package and they must to deliver it.

            var smallSpecialGift = new SpecialFilledAndDecoratedGiftBox(2, "Yellow");

            deliveryService.DeliverGift(smallSpecialGift);

            var bigSpecialGift = new SpecialFilledAndDecoratedGiftBox(17, "Red");

            deliveryService.DeliverGift(bigSpecialGift);
        }