Python 计时用装饰器

def time_it(method):                                                           
                                                                               
    def timed(*args, **kw):                                                    
        start_time = time.time()                                               
        result = method(*args, **kw)                                           
        end_time = time.time()                                                 
        print '%r (%r, %r) %2.2f sec' % \                                      
              (method.__name__, args, kw, end_time-start_time)                 
        return result                                                          
                                                                               
    return timed