mass_update_fields doesn't work

[tolomea]

Looking here https://github.com/saxix/django-adminactions/blob/edbfed7714c9455e92bf8d9407dda37c68aea26a/src/adminactions/mass_update.py#L277

    mass_update_exclude = getattr(modeladmin, 'mass_update_exclude', ['pk']) or []
    if 'pk' not in mass_update_exclude:
        mass_update_exclude.append('pk')

So mass_update_exclude can't ever be False. Then a couple of lines later:

    if mass_update_fields and mass_update_exclude:
        raise Exception("Cannot set both 'mass_update_exclude' and 'mass_update_fields'")

So you cannot ever set mass_update_fields...