Earlier quoted context omitted.
I'd like to support 3.x at some point. See https://github.com/google/grumpy/issues/1
Have you thought about using type hints to help type inference? Some work on that is discussed here. I would love a dropbox google colab (though also targeting 3.x :) ) https://github.com/python/mypy/issues/1862
One of the goals of open sourcing was to get feedback and work with outside folks so I'm definitely open to collaboration!