python 闭包

def sumlist(*arg):
    return sum(arg)
def averageList(*arg):
    return sum(arg)*1.0/len(arg)
def dec(func):
    def in_dec(*args):
        if len(args)==0:
            return 0
        for each in args:
            if not isinstance(each, int):
                return 0
        return func(*args)#这里args前面必须有*
    return in_dec
num=[1,2,3]
sum1 = dec(sumlist)
print sum1(*num)#必须传入元组，列表前必须加*
print sum1(*[1,2,3])#必须传入元组，列表前必须加*
print sum1(1,2,'3')#或者以这种形式传入
ave1 = dec(averageList)
print ave1(1,2,3,4)
print ave1(1,2,3,4,'3')