#!/usr/bin/env python# -*- coding: utf-8 -*-# __author__ = 'https://github.com/faif'import timeclass SalesManager:    """真实实体类对象, 它就没有采用公共接口."""    def work(self):        print("Sales Manager working...")    def talk(self):        print("Sales Manager ready to talk")class Proxy:    """    代理类, 需要加载(SalesManager())真实实体类对象,     利用这个真实实体类所提供的方法为外部人员提供服务    """    def __init__(self):        self.busy = 'No'        self.sales = None    def work(self):        print("Proxy checking for Sales Manager availability")        if self.busy == 'No':            self.sales = SalesManager()            time.sleep(2)            self.sales.talk()        else:            time.sleep(2)            print("Sales Manager is busy")class NoTalkProxy(Proxy):    def __init__(self):        Proxy.__init__(self)    def work(self):        print("Proxy checking for Sales Manager availability")        time.sleep(2)        print("This Sales Manager will not talk to you whether he/she is busy or not")if __name__ == '__main__':    p = Proxy()    p.work()    p.busy = 'Yes'    p.work()    p = NoTalkProxy()    p.work()    p.busy = 'Yes'    p.work()