class Instrument:
    """基类：乐器"""
    def play(self):
        print("乐器在演奏声音")

    def __del__(self):
        pass

class Piano(Instrument):
    """子类：钢琴"""
    def play(self):
        print("钢琴：叮咚叮咚")

class Guitar(Instrument):
    def play(self):
        print("吉他：咚咚当当")

if __name__ == "__main__":
    instruments = [Piano(), Guitar()]

    for inst in instruments:
        inst.play()