Loading collection data...
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.
filter function should only return a boolean value.
Sounds like maybe some issues with your tests.
Maybe try something like:
Ok, now it worked, but only when I submitted my solution. When I ran the test it returned me an error.
"Incorrect! Test didn't pass: Unknown error"
What is the failure message?
I've tried copy/pasting your solution into the trainer, and it passes.
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