singleton using metaclass

[bb8]

i need to write a singleton so i looked up some examples. here's one of them from https://stackoverflow.com/questions/6760...on#6798042

class _Singleton(type):
    """ A metaclass that creates a Singleton base class when called. """
    _instances = {}
    def __call__(cls, *args, **kwargs):
        if cls not in cls._instances:
            cls._instances[cls] = super(_Singleton, cls).__call__(*args, **kwargs)
        return cls._instances[cls]

class Singleton(_Singleton('SingletonMeta', (object,), {})): pass

class Logger(Singleton):
    pass

i've just read about metaclasses but i don't understand how the above example uses a metaclass. shouldn't it be? -->

class _Singleton(type):
    """ A metaclass that creates a Singleton base class when called. """
    _instances = {}
    def __call__(cls, *args, **kwargs):
        if cls not in cls._instances:
            cls._instances[cls] = super(_Singleton, cls).__call__(*args, **kwargs)
        return cls._instances[cls]

class Singleton(metaclass=_Singleton('SingletonMeta', (object,), {})): pass # notice the metaclass

class Logger(Singleton):
    pass

however i still want isinstance(inst, Singleton) to be True.