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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.
It's totally hardcoded :D
Why does this work?
what
Spelling and grammar issues with the test cases. The bottom most case kind of implies that it should both return null and something non-null (but you can reasonably assume that this is a mistake and you should return something non-null).