Singleton implantation on Python

singleton.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

class Singleton(type):
    def __call__(self, *args, **kwargs):
        if 'instance' not in self.__dict__:
            self.instance = super(Singleton, self).__call__(*args, **kwargs)
        return self.instance


class CoolFeautre(object):
      __metaclass__ = Singleton


print CoolFeautre()
print CoolFeautre()