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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.
len function takes list as argument.Check what is the type of argument you have mentioned in len function
There seems to have a problem with the python tests. I get:
Traceback:
in
in tester
TypeError: object of type 'NoneType' has no len()
It seems that you forgot to test if h>0.