def _last_index(self, s):
        self.set_index(max(0, self._find_one_after_last_labeled_index() - 1))
def edit_forum(forum_id):
    forum = Forum.query.filter_by(id=forum_id).first_or_404()

    form = EditForumForm(forum)
    if form.validate_on_submit():
        form.save()
        flash(_("Forum updated."), "success")
        return redirect(url_for("management.edit_forum", forum_id=forum.id))
    else:
        if forum.moderators:
            form.moderators.data = ",".join([
                user.username for user in forum.moderators
            ])
        else:
            form.moderators.data = None

    return render_template("management/forum_form.html", form=form,
                           title=_("Edit Forum"))