Running FACE with no immutable features

[melfranks]

Hi, thanks so much for this library, it's been incredibly useful to me!

I'm using FACE to generate counterfactuals with my own datasets and models, and it works fine when I set at least one feature as immutable. However, ideally I'd like to set all features to mutable. When I try to do this by setting 'immutables' as an empty list, see screenshot:

I get the error shown below.

Is there a way to do this, or would it be possible to add this option in future? Thanks!