public function get_files($includedirs = true, $updatedsince = 0) {

        $lesson = lesson::load($this->properties->lessonid);
        $fs = get_file_storage();
        $answerfiles = $fs->get_area_files($lesson->context->id, 'mod_lesson', 'page_answers', $this->properties->id,
                                            'itemid, filepath, filename', $includedirs, $updatedsince);
        $responsefiles = $fs->get_area_files($lesson->context->id, 'mod_lesson', 'page_responses', $this->properties->id,
                                            'itemid, filepath, filename', $includedirs, $updatedsince);
        return array_merge($answerfiles, $responsefiles);
    }