使用元類

元類語法

Python 2.x <= 2.7

class MyClass(object):
    __metaclass__ = SomeMetaclass

Python 3.x >= 3.0

class MyClass(metaclass=SomeMetaclass):
    pass

Python 2 和 3 與 six 的相容性

import six

class MyClass(six.with_metaclass(SomeMetaclass)):
    pass