Under the comment box, there is a checkbox with the text "Mark as having spoiler content". And after you posted it, between View Solution and Remove, there is Spoiler with a flag icon. That'll mark your post as hidden for people that didn't solve the kata yet.

Well, I guess it was just beacuse this was my first ever kata, I kept trying to actually have a list and so it would colide with the tests... just write the code but don´t write a list y´all! However stupid this sounds it would´ve helped me so I hope to help someone else