Yes, Unnamed, you're entirely correct and this definitely should come under 'clever' rather than 'best practice'.

Additionally + constructs a new list, which is rather inefficient. I don't know about * though. Have a look at my solution, iterators are made for such things.

It doesn't really matter since for a solution written just for looks anything goes while for an optimal solution creating a list of (possibly 10000) Nones just to traverse it once and destroy is strange anyway.

You're correct. I used just [None]*len(keys) for the sake of brevity, but ideally you'd use [None]*(len(keys) - len(values)) in practice.