def __repr__(self):
        return "<Requirements({})>".format(self.filename.name or "")
def unban_user(user_id=None):
    if not Permission(CanBanUser, identity=current_user):
        flash(_("You do not have the permissions to unban this user."),
              "danger")
        return redirect(url_for("management.overview"))

    # ajax request
    if request.is_xhr:
        ids = request.get_json()["ids"]

        data = []
        for user in User.query.filter(User.id.in_(ids)).all():
            if user.unban():
                data.append({
                    "id": user.id,
                    "type": "unban",
                    "reverse": "ban",
                    "reverse_name": _("Ban"),
                    "reverse_url": url_for("management.ban_user",
                                           user_id=user.id)
                })

        return jsonify(
            message="{} users unbanned.".format(len(data)),
            category="success",
            data=data,
            status=200
        )

    user = User.query.filter_by(id=user_id).first_or_404()

    if user.unban():
        flash(_("User is now unbanned."), "success")
    else:
        flash(_("Could not unban user."), "danger")

    return redirect(url_for("management.banned_users"))