Hi @steven.daprano, @gregory.p.smith. I added the first version of my PR for review.

One issue with it is that in:

def f():
    return "   foo".dedent()

f will have both "   foo" and "foo" in its constants even if the first is not used anymore. Removing it requires looping over the code once more while marking the constants seen in a set and I was not sure if this was ok.