Thank you so much! I didnt know what was wrong with my code so I decided to look here. I certainly didnt know about the throw statement

seems it should be a 6 kyu for the Python version. perhaps more snags with other langs, e.g. JS sort instability? and so I take kyu levels with a grain of salt. for example, I come across challenges from time to time where Python fails to cut the mustard speed-wise

Sorry about that.. fixed now. :)

Didn't see the first restriction and my code does follow the second one. The body of the function square is clearly shorter than 25 characters.

Please read the description carefully.

return any one of them.

( My emphasis )