> L := [[1, 2], [3, 4], [-5, 7]]:
> OptionalSort(L);
                   [[-5, 7], [1, 2], [3, 4]]
> OptionalSort(L, reverse);
                   [[3, 4], [1, 2], [-5, 7]]
> OptionalSort(L, reverse, column = 2);
                   [[-5, 7], [3, 4], [1, 2]]