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.
You get that error because you can't run tests. The author has configured the tests to show you how the tail and loop are created.
That said i'm confused as heck about what the Node even has. It doesn't seem to have a value available with
.valueso how we determine loop from tail I have no idea