def test_add_already_added(self):
        prio_set_list = event._PrioritizedSetList()
        obj = object()
        prio_set_list.add(0, obj)

        with pytest.raises(ValueError) as excinfo:
            prio_set_list.add(0, obj)
        excinfo.match(r"has already been added")

        with pytest.raises(ValueError) as excinfo:
            prio_set_list.add(1, obj)
        excinfo.match(r"has already been added")
def add_category():
    form = CategoryForm()

    if form.validate_on_submit():
        form.save()
        flash(_("Category added."), "success")
        return redirect(url_for("management.forums"))

    return render_template("management/category_form.html", form=form,
                           title=_("Add Category"))