public function redo_question_button($slot, $disabled) {
        $attributes = array('type' => 'submit',  'name' => 'redoslot' . $slot,
                'value' => get_string('redoquestion', 'quiz'), 'class' => 'mod_quiz-redo_question_button');
        if ($disabled) {
            $attributes['disabled'] = 'disabled';
        }
        return html_writer::div(html_writer::empty_tag('input', $attributes));
    }