public function files_read_only(question_attempt $qa, question_display_options $options) {
        $files = $qa->get_last_qt_files('attachments', $options->context->id);
        $output = array();

        foreach ($files as $file) {
            $output[] = html_writer::tag('p', html_writer::link($qa->get_response_file_url($file),
                    $this->output->pix_icon(file_file_icon($file), get_mimetype_description($file),
                    'moodle', array('class' => 'icon')) . ' ' . s($file->get_filename())));
        }
        return implode($output);
    }