Oh brilliant to encode the missing bar versions!

I can only speak for myself, but I had originally used itertools.permutation() to split the given number into an array of all of its permutations and then sort through to find the lowest number greater than the original. This worked for the test cases but not when I actually attempted since really large numbers timeout as this algorithm is super inefficient.

So I changed the whole gameplan and simply forgot to change the 'import itertools' line at the top.

I can't get around the need for arguments. In order to pass in the operation functions into the first number, we need to require an argument. But since the second number doesn't take an argument, we can't require one.... So do we have to write two functions for each number?

This is very poorly worded, imo. It's not clear that we will be given multiple triplets containing the same letters from the string. Like 'howareyou' could have the triplets: 'hwr', 'wae', 'hyo', 'wry', etc. The way it's worded made it seem like each letter would only show up in ONE of the triplets, which would be nearly impossible to solve.