Yeah, it's a very poor problem statement.

I don't understand this too. It's the same problem that I had.

Extremely strange test results - [0, 2, 2, 0]: it returns [2, 2, 0, 0] for me - the test writes that it is not true and should return [2, 2, 0, 0]. What's wrong here???

Difficult to understand explanation. Tell me, do we remove W <-> E or S <-> N only if they are near? That is, in W, E, W, S, E, do we delete W and E? And there remains W, S, E?

Have you already read that link?

please tell me the solution
I have the same problem

return digital_root(x) !!!!!

Teach me, I haven't studied this yet)))
Tried:
return x
return n
but the result is the same

You are missing a return statement at the last line: else: digital_root(x). Currently, your code returns None to console.

you need a return statement on the last line

next: have you printed your evenSum and oddSum to see what results you're getting?