human
I am working on the file "DesignPattern/CommandPattern.ipynb".
The first task is:
前台服务员系统与后台系统的交互，我们可以通过命令的模式来实现，服务员将顾客的点单内容封装成命令，直接对后台下达命令，后台完成命令要求的事，即可。前台系统构建如下：
Can you write Python program for it?
 What is a the Python program you requested?
assistant
#Here is the Python program you requested.

class waiterSys():
    def __init__(self):
        self.menu_map=dict()
        self.commandList=[]
    def setOrder(self,command):
        print ("WAITER:Add dish")
        self.commandList.append(command)

    def cancelOrder(self,command):
        print ("WAITER:Cancel order...")
        self.commandList.remove(command)

    def notify(self):
        print ("WAITER:Nofify...")
        for command in self.commandList:
            command.execute()