private void Start()
{
Barbecuer boy = new Barbecuer();
Guest guest_01 = new Guest(new BakeMuttonCommand(boy));
Guest guest_02 = new Guest(new BakeMuttonCommand(boy));
Guest guest_03 = new Guest(new BakeChickenWingCommand(boy));
Waiter girlWaiter = new Waiter();
girlWaiter.SetOrder(guest_01._command);
girlWaiter.SetOrder(guest_02._command);
girlWaiter.SetOrder(guest_03._command);
girlWaiter.Notify();
girlWaiter.CancelOrder(guest_01._command);
girlWaiter.Notify();
}