No, you didn't have to? What you call answers is actually the answer key, and what you call key are the student's answers, and you treat them as such. You switched the names, but you did not switch the meanings.

ah yeah re-read -> strange definition of scoring 100% though: getting them all wrong.

Thanks though

In python I had to switch the order of (key, answers) in the solution setup because it doesn't match the order for those two given in the test cases

There is more than one way to earn a perfect score.

Not a kata issue.

not sure the test are right for python eg

test.assert_equals(possibly_perfect(['A', 'B', 'A', '_'], ['B', 'A', 'C', 'C']), True)

seems like the student answered question B, but the answer was A, so the student will not be able to have a perfect score