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.
Others have mentioned this, but I'm raising it as an issue.
Kata should have us raise exception, not return error strings. Specify which type of exception to raise and what custom message to use for each error you want to check.