I think the Kata description can be greatly improved. Although it is not too difficult, for beginners it might be confusing what is actually being asked. At this level they should be spinning their wheels on how to get syntax right and properly structuring their code, not figuring out what the question is asking.

This is too easy to be a 7 kyu, should be an 8 kyu

Need better and/or more test cases on this Kata as code is being accepted but gives wrong output in certain edge cases

Because people don't actually know how to read code or check to see if actually works. They think it is "clever" just because it is on one line.