This error does not try to tell you that tests think you are cheating. On the contrary, there are some tests titled "No cheating!" (maybe not the most fortunate title for a test group), and all of them pass. It means that tests did not detect any disallowed things in your solution.

The error you get is indeed not really clear. I was able to reproduce it returning None from my solution, so I expect you have some branch in your code which falls off the function without returning anything.

Well thats strange as I've not used it. Wonder what's triggering it.

That's not cheating. The tests in that kata check that you're not using eval and similar work-arounds.

What cases are considered cheating? I have just spent so time creating a solution for https://www.codewars.com/kata/5235c913397cbf2508000048 within my IDE and once copy pasted into the web ui I have a cheating error. I may have missed a rule and this is considered cheating but if somebody could inform me on how to avoid or not cheat, that would be very helpful. Due to the solution working but with the cheating error I can provide it if requested.

Thanks,
GDWR

Screenshot of error: https://prnt.sc/tsaly1