>>>> l=[(1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,)]
>>> sum(map(sum,l))
18
>>> l[0]=(1,2,3,)
>>> l
[(1, 2, 3), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,), (1,)]
>>> sum(map(sum,l))
23