I don't remember the details, but don't sort oeprations operators require *strict* ordering? I mean:
1. less is `<`
2. more is `>=`

I mean: I think sort theory allows to have neither `more(a, b)` nor `more(b, a)`, but not `more(a, b)` *and* `more(b, a)`. I'm not sure, but it could use a double check.

Could you at least add a test case where you lazily sort with duplicates?