由http://www.mamicode.com/info-detail-2348797.html遇到此匿名函数问题
def num():
    return [lambda x:i*x for i in range(4)]
print(m(2) for m in num())# <generator object <genexpr> at 0x0000000000B2FA40> 为元祖
print(list(m(2) for m in num())) # [6, 6, 6, 6]