import time

def performance(unit):
    def performance1(f):
        def fn(*args,**kw):
            t1=time.time()
            r=f(*args,**kw)
            t2=time.time()
            if (unit=='ms'):
                print 'call %s() in %f %s'(f.__name__,(t2-t1)*1000,unit)
            print 'call %s() in %f %s'(f.__name__,(t2-t1),unit)
            return r
        return fn
    return performance1

@performance('ms')
def factorial(n):
    return reduce(lambda x,y: x*y, range(1, n+1))

print factorial(10)