import time

def performance(f):

    def fn(*args,**kargs):

        t1 = time.time()

        r = fn(*args,**kargs)

        t2 = time.time

        print('call %s() in %fs '%(f.__name__,(t2-t1)))

        return r

    return fn

@performance

def factorial(n):

    return reduce(lambda x,y: x*y, range(1, n+1))

print factorial(10)