Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
Not an issue. Your solution is wrong, and that's causing the error.
Your code is returning something wrong, it wasn't either None or a two element list.