When I run the nox tests for Python 3.7 through 3.9, they all fail with messages similar to failed to find interpreter for Builtin discover of python_spec='python3.8'. Reproduction: simply run nox -r at the top of this repo.

When we stop supporting Python 3.7 and 3.8 we should remove those nox sessions from our test suite.

We should keep the Python 3.9 test suites while we support Python 3.9, but we should fix whatever is causing them to fail locally.

As we do the above, we should check what the behavior is pre-submits.