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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.
I guess original tests were not so harsh
That is one of the assumptions, if Batman:[Superman] happens, since the hate is mutual, you will also receive as input Superman:[Batman]. No need to check it :D
Read the problem description.