Super fancy list constructing in Python
I'm severely confused by array.move_down, because I don't see any array or anything moving anywhere. If you are doing a super_list, wouldn't it be more readable to have sublist.begin and sublist.end?

Also I don't like fail-later approach with hiding an exception. If user makes an error in nesting lists, I would fail fast instead. It's a common behavior of all the languages I know (with an exception of early/ancient HTML).