class Singleton:
    def __call__(self, func):
        def wrapper(*args, **kwargs):
            res = func(*args, **kwargs)
            return res
        return wrapper

    def __new__(self, *args, **kwargs):
        if not hasattr(self, '_instance'):
            self._instance = super().__new__(self, *args, **kwargs)
        return self._instance

@Singleton()
def MyClass():
    time.sleep(1)

if __name__ == "__main__":
    s1 = MyClass()
    s2 = MyClass()
    print(id(s1), id(s2))
    print(s1 is s2)