@classmethod
def get_request_queryset(cls, ar, **filter):
    """Return the base queryset for tables on this object.

        The optional `filter` keyword arguments, if present, are
        applied as additional filter. This is used only in UNION
        tables on abstract model mixins where filtering cannot be done
        after the join.

        """
    qs = cls.get_user_queryset(ar.get_user(), **filter)
    if ar.actor.only_fields is not None:
        qs = qs.only(ar.actor.only_fields)
    return qs
