@Lex88 for python - use print() statements inside your function.

This is a bit offtopic but how do i see what the testcase 5 is?
I am also failing just this one test but I don't know how it failed.

You're reading the logs wrong, they appear above the test result. That's not the input of the test your code fails.

You have to press the attempt button-to the righ of the test button. This gives more tests. If you get all of those correct, the green submit button appears (in place of the attempt button), and when you press that, it submits you solution.

The "test" button will only run a few tests. After that passes you shold use the "attempt" button and that should do it.