Singleton dp in Python

singleton.py

class Singleton(type):

    def __init__(cls, name, bases, attrs, **kwargs):
        super().__init__(name, bases, attrs)
        cls._instance = None

    def __call__(cls, *args, **kwargs):
        if cls._instance is None:
            cls._instance = super().__call__(*args, **kwargs)
        return cls._instance


class SingletonClass(metaclass=Singleton):
    pass

if __name__ == "__main__":    
    obj1 = SingletonClass()
    obj2 = SingletonClass()
    print(obj1 is obj2)
    print(id(obj1))
    print(id(obj2))
    
#OUTPUT
#True
#140189813742112
#140189813742112