一段代码

class Chain(object):
    def __init__(self,path=str()):
        self.__path=path
        #print self.__path,‘echo from __init__‘

    def __getattr__(self,path):
        #print ‘called __getattr__‘
        return Chain(‘%s/%s‘ %(self.__path,path))

    def __str__(self):
        print ‘called __str__‘
        return self.__path

print Chain().status.other

# 如果将以上代码中的注释去掉的话

 echo from __init__
called __getattr__
/status echo from __init__
called __getattr__
/status/other echo from __init__
called __str__
/status/other

Chain().status返回Chain()对象，继续调用 other，如此循环