(apart from small fixes relating to borrowed references, and
that's mostly to make PyPy's life easier).

Speaking as the Gilectomy guy: borrowed references are evil.  The definition of the valid lifetime of a borrowed reference doesn't exist, because they are a hack (baked into the API!) that we mostly "get away with" just because of the GIL.  If I still had wishes left on my monkey's paw I'd wish them away*.

/arry

* Unfortunately, I used my last wish back in February, wishing I could spend more time at home.