# -*- coding: utf-8 -*-


# 子系统
class Dog(object):
    def say_hi(self):
        print("汪汪汪...")


class Cat(object):
    def say_hi(self):
        print("喵喵喵...")


# 门面
class Zoo(object):
    def animal_say_hi(self):
        dog = Dog()
        dog.say_hi()

        cat = Cat()
        cat.say_hi()


# 客户端
class Visitor(object):
    def visit(self):
        zoo = Zoo()
        zoo.animal_say_hi()


if __name__ == '__main__':
    visitor = Visitor()
    visitor.visit()
    """
    汪汪汪...
    喵喵喵...
    """