Incompatible with Python 3.10

[christianbundy]

This module uses:

from collections import Iterable

But in Python 3.10, we need:

from collections.abc import Iterable

[christianbundy]

Oops -- should've mentioned this, but I saw that this was fixed in #265 -- @chrislit can I do anything to help cut a new release?

[chrislit]

Hi @christianbundy, I'm working on a new release now, but it may take a while. There's a lot of broken stuff that needs fixing (mostly unit tests & CI stuff; the tests seem to pass on 3.9 & 3.10, though), I'll also do a round of optimizations now that I'm dropping support for 3.5, and I'll try to clear some of the other issues raised recently.

[christianbundy]

Anything I can help with? My goal is to avoid adding Git to my build environment just to pull from GitHub, so even pushing an alpha pre-release to PyPI would be super helpful.