def save(self, filename=None):
        filename = Path(filename) if filename is not None else self.filename
        with filename.open("w") as f:
            f.write(self.yaml)
def delete_forum(forum_id):
    forum = Forum.query.filter_by(id=forum_id).first_or_404()

    involved_users = User.query.filter(Topic.forum_id == forum.id,
                                       Post.user_id == User.id).all()

    forum.delete(involved_users)

    flash(_("Forum deleted."), "success")
    return redirect(url_for("management.forums"))