It might be better if we could avoid using `eval` in this module. @cowlicks suggested this on another PR, and I agree with him. The `__main__` code block could just do string comparisons vs the command and call it directly, as I did in `purge_cluster.py`.

This is somewhat past the scope of this PR, but if we are changing this file, it could be a good time to change that.

P.S. I would have put this note with the `eval` command but github wouldn't let me.