It looks like you expect `user_options` to be either a `list` or not specified, so making the default an empty string is a little misleading.  I'd find it clearer if you:

1) Make the default `None`, then check `user_options is not None` below (instead of checking that it's `False`).
2) Add a comment to the docstring explaining that `user_options`, if provided, should be a list.