Evan dev

[eschechter]

I think what would be most helpful for @chrisrossi to do would be to review the docstrings and any glaring code style issues. We know the repo works functionally due to ipldstore, and I don't think there's time for Chris to really immerse into the codebase.

[chrisrossi]

As far as code formatting, I highly recommend the use of black for automatically formatting code to conform to PEP8. It is something of a standard now to add this and flake8 to tox to use as part of acceptance testing in continuous integration environments.

[chrisrossi]

This looks great! A few little niggles and some suggestions/commentary.

[chrisrossi]

LGTM. Consider giving "mask_fun" a more transparent name, but there are no blockers here.