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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 a double negation. First it negates a false-ish value (nil or false) to true and then negates it false. With this method you have only true or false output and not true, false or nil.