"XIIX" isn't a valid Roman numeral either way.

guys ours looks the best 😎

Why is the Roman numeral not valid?

XIIX: A numeral of lower value, I ( = 1), may not stand in front of a group of numerals in subtractive notation, IX ( = 9).

Why is this not being upvoted? IMO the cleanest and the most straightforward to understand.
Oh yes I know why. Because someone wrote a bedsheet of code above and nobody scrolls here :)

This is very clean.

Not an issue

Give a little more description-otherwise looks great

Sounds good!

Thanks for the suggestion, but this kata is aimed at students in a software design class that haven't learned about functions, parameters, or return values yet. We cover that during the third week of class.

This is a great idea for a kata! The only this is it's really hard to understand. As someone who has worked with Python a lot, it isn't too bad to work through what is going on. I think you should change the setup of the kata to resemble most other kata (i.e. a function that accepts an input). Otherwise, I think it is ready to go.

Wow.