Creating a Singleton in Python

singleton.py

class Singleton(type):
    def __init__(cls, name, bases, dict):
        super(Singleton, cls).__init__(name, bases, dict)
        cls.instance = None

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


class MySingleton(object):
    __metaclass__ = Singleton


a = MySingleton()
b = MySingleton()
c = MySingleton()

print a is b
print b is c
print a is c
print
print a == b
print b == c
print a == c
print
print hash(a)
print hash(b)
print hash(c)