一个出错的Mixin例子

想学习下Mixin技术，不过看到个基本的例子都报错，实在是没办法高手指定下吧，多谢！
main.py:
-------------------------------------------------
import Mixin
import mPrint

class A(Mixin.Mixin):
    __mixinname__ = 'a'

    def __init__(self):
        self.initmixin()
        self.callplugin('init', self)



if __name__ == '__main__':
    a = A()
    a.Print()
---------------------------------------
mPrint.py
-------------------------------------

#! /usr/bin/env python
#coding=utf-8
import Mixin

def init(self):
    self.name = 'mPrint.py'
Mixin.setPlugin('a', 'init', init)

def Print(self):
    print self.name
Mixin.setMixin('a', 'Print', Print)


报错信息如下：
> "E:\Python25\pythonw.exe" -u "...\itipsource\Mixin\main.py" 
Traceback (most recent call last):
  File "....\itipsource\Mixin\main.py", line 16, in
    a = A()
  File "...\itipsource\Mixin\main.py", line 10, in __init__
    self.initmixin()
  File "E:\Python25\Mixin.py", line 52, in initmixin
    debug.info('[Mixin] Dealing class [%s]' % self.__class__.__name__)
AttributeError: 'NoneType' object has no attribute 'info'