原來如此，謝謝啦

from?functools?import?reduce

def?calc_prod(list_):
????def?lazy_prod():
????????def?f(x,?y):
????????????return?x?*?y
????????return?reduce(f,?list_,?1)
????return?lazy_prod

f?=?calc_prod([1,?2,?3,?4])
f()

在最后一行代碼前面加上print?

更改后為print f()