Please see if this helps: https://docs.codewars.com/training/troubleshooting#print-input

I cannot figure out, how input (or print) may help in this case? could you explain it please. I have the same problem and it really drives me crazy

Print input to console

Thank you! Now I solved the issue) I didn't use print() here before this Kata.

a or b might be nil or null or None or nothing (except in C++, Elixir, Haskell, PureScript, Pascal, Perl, R, Rust, Shell).

Yes, try printing the input.

Traceback (most recent call last):
File "/workspace/default/src/codewars-test/codewars_test/test_framework.py", line 111, in wrapper
func()
File "tests.py", line 25, in basics
test.assert_equals(comp(a1, a2), False)
File "/workspace/default/solution.py", line 4, in comp
array2.sort()
AttributeError: 'NoneType' object has no attribute 'sort'

My func can pass 105 testcases... But something ruine my code. I guess it someting like Null or None instead of Array2