Why?

Your code is wrong, it's not a kata issue.

8 + 8 = 16, 16 is a two digit number... so you have to repeat the process. 1 + 6 = 7. 7 is not even.

broken
8+8 = 16 not even?

Which part exactly?
Reading this solution I learnt that one could aggregate lists with a "+":
["a", "b"] + ["c", "d"] = ["a", "b", "c", "d"]
Does this help understanding?

could someone explain

bad kata

Passed it after many tries lol.. who is lying, the random test or statistic.median...?

I think when they were unable to make it, unlocked solutions and copied to see how it works

overcomplicated

I think they have left programming after this kata

arr = sorted(arr) isn't mutating the input? wheres the difference

Yeah, exactly

Thanks, I got it because of your explanation

Best practice?...