# _*_ coding: utf-8 _*_
import functools, time
def metric(func):       
    @functools.wraps(func)   
    def wrapper(*args, **kw):
        a = time.time()
        f = func(*args, **kw)
        b = time.time()
        print('execute %f seconds' % (b-a))
        return f
    return wrapper