Book sections are usually numbered as x.x.x
Why not store the section numbers as tuples?
sections = [(2, 4, 1), (1, 10, 3),(1, 2, 1), (1, 1, 10), (1, 2, 3), (1, 4, 6)]
print(sorted(sections))
gives
[(1, 1, 10), (1, 2, 1), (1, 2, 3), (1, 4, 6), (1, 10, 3), (2, 4, 1)]