python单例模式

class Person():
    __instance=None
    @classmethod
    def get_instance(cls):
        if cls.__instance:
            return cls.__instance
        else:
            cls.__instance=Person()
            return cls.__instance
        

if __name__=='__main__':
    p1=Person.get_instance()
    p2=Person.get_instance()
    p3=Person.get_instance()
    print(p1)
    print(p2)
    print(p3)