#练习
import time,functools
def metric(fn):
    @functools.wraps(fn)
    def wrapper(*args,**kw):
        start=time.time()
        fn(*args,**kw)
        end=time.time()
        print('%s execute in %s ms' %(fn.__name__,end-start))
        return fn(*args,**kw)
    return wrapper

@metric
def fast(x,y):
    time.sleep(0.0012)
    return x+y

f=fast(11,22)
print(f)

#思考一：
import functools

def log(func):
    @functools.wraps(func)
    def wrapper(*args,**kw):
        print('begin call %s()' % func.__name__)   
        func(*args,**kw)
        print('end call %s()'% func.__name__)
    return wrapper

@log
def now():
print('2018-10-4')

now()
print (now.__name__)

#思考二
import functools

def log(*nub): #可变参数即可满足
    def decorator(func):
        @functools.wraps(func)
        def wrapper(*args,**kw):
            print(nub)
            print('%s %s()' % (nub,func.__name__))        
            func(*args,**kw)
            print('end %s()'% func.__name__)
        return wrapper
    return decorator

@log('execute') 
def now():
print('2018-10-4')

now()
print (now.__name__)