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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.
You are probably getting tabs and spaces somehow mixed up in your solution. The problem is not related to sorting.
Check in your IDE if you use spaces and tabs for indentation consistently. Initial solution does indeed use both (and it's not good), but you have to be really unlucky to get bitten by it in such small stub :)