public function prepare_response_files_draft_itemid($name, $contextid) {
        foreach ($this->get_reverse_step_iterator() as $step) {
            if ($step->has_qt_var($name)) {
                return $step->prepare_response_files_draft_itemid($name, $contextid);
            }
        }

        // No files yet.
        $draftid = 0; // Will be filled in by file_prepare_draft_area.
        file_prepare_draft_area($draftid, $contextid, 'question', 'response_' . $name, null);
        return $draftid;
    }