class Appliance:
    def power_on(self):
        pass

    def power_off(self):
        pass

class TV(Appliance):
    def power_on(self):
        print("TV 전원 켬")

    def power_off(self):
        print("TV 전원 끔")

class AirConditioner(Appliance):
    def power_on(self):
        print("에어컨 가동")

    def power_off(self):
        print("에어컨 종료")

class HomeManager:
    def __init__(self):
        self.appliances = []

    def add_appliance(self, appliance):
        self.appliances.append(appliance)

    def all_off(self):
        for appliance in self.appliances:
            appliance.power_off()


manager = HomeManager()

tv = TV()
ac = AirConditioner()

manager.add_appliance(tv)
manager.add_appliance(ac)

tv.power_on()
ac.power_on()

print("\n모든 기기 전원 끄기:")
manager.all_off()