protected function build_currentdata($grouped, $data) {
        // Check the grouped already exists into currentdata
        if (!is_array($this->currentdata) or !array_key_exists($grouped, $this->currentdata)) {
            $a = new stdclass();
            $a->grouped = $grouped;
            $a->child = $data['path'];
            throw new progressive_parser_exception('xml_cannot_add_to_grouped', $a);
        }
        $this->add_missing_sub($grouped, $data['path'], $data['tags']);
    }