Add Missing Docstrings

[MaggieFero]

Is your feature request related to a problem? Please describe.
The codebase currently has five instances of the linter exemption "# pylint: disable=missing-function-docstring", most of which are in tests and one of which is currently annoying me as I try to debug the thing that does not have the docstring.

Describe the solution you'd like
I should go through and write the docstrings once we have this repo back into a stable state.

Describe alternatives you've considered
We shouldn't be considering alternatives to writing the docstrings imo, we should just do it.

Additional context
Docstrings are currently missing in three tests as well as erase_deleted_user_data.py, but we should just search for the linter exception once we're ready to work on this in case it's changed.