I don't understand this Kata for Python 3.6.

So I'm supposed to take a single list and split it into two, right?

So why are there three inputs: source, front, back?

I thought the first thing I'd do is print all three inputs to try and figure this out, or at least just understand what form this list is arriving... but all I get back is a reference to the Node object which I don't feel has been properly explained.

Anyone able to clear up what these instructions want me to do for a Python 3.6 implementation?

This was the issue.

I was dropping values from the list if they didn't have a pair and mutating the original list. Quite difficult to debug!

Copying the list solved this issue. I can see the argument for not passing a copy, equally, I wasn't aware the same list was going to be reused in mutliple tests. Maybe some test to check the list hasn't been mutated?

Ah, I was reading the wrong log.

Still have the same issue...

num ints:9999998, s:16
Counter({1: 9999994, 6: 1, 7: 1, 8: 1, -3: 1})

I still don't see a valid pair there that sums to 16.

I'm using Python 3.6.