# /usr/bin/python# -*- coding:utf-8 -*-from time import timedef logged(when):    def log(f,*args,**kargs):        print  '''                  called:                    functions:%s                    args: %r                    kargs: %r        '''   % (f,args,kargs)        def pre_logged(f):        def wrapper(*args,**kargs):            log(f,*args,**kargs)            return f(*args,**kargs)        return wrapper    def post_logged(f):        def wrapper(*args,**kargs):            now = time()            try:                return f(*args,**kargs)            finally:                log(f,*args,**kargs)                print "time delta:%s" % (time()-now)        return  wrapper    try:        return {
   "pre":pre_logged,"post":post_logged}[when]    except KeyError,e:        raise ValueError(e),'must be "pre" or "post"'@logged("post")def hello(name):    print "hello,",namehello("world!")'''等同于： hello = logged("post")(hello("world!"))'''