Python 元类的例子

#coding:utf-8
class FA(type):
    def __new__(cls, name, base, attr):
        print name
        print base
        print attr
        print "it is in fa's new"
        new_obj = super(FA, cls).__new__(cls, name, base, attr)
        return new_obj


class FB(object):
    __metaclass__ = FA
    def __init__(self):
        print "it is in FB's init"
        
b = FB()

结果是：
C:\>python test.py
FB
(,)
{'__module__': '__main__', '__metaclass__': , '__init__': }
it is in fa's new
it is in FB's init