def get_field_queryset(self, db, db_field, request):
        if db_field.name == "discipline":
            # Filter the discipline field's queryset based on the parent journal's type.
            if request._obj:
                return db_field.remote_field.model._default_manager.using(db).filter(
                    type__code=request._obj.type.code
                )
            # If there is no parent journal (during journal creation), return an empty queryset.
            else:
                return db_field.remote_field.model._default_manager.using(db).none()
        return super().get_field_queryset(db, db_field, request)