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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.
Scala description needs update: the description claims you must return false for invalid input, but the tests expect an empty string.
Returning empty string is more sensible behaviour, please update the description to reflect this.