private function indexCompare(array $a, array $b): int {
        if ($a['columns'] > $b['columns']) {
            return 1;
        } elseif ($a['columns'] < $b['columns']) {
            return -1;
        }

        return strcmp(
            isset($a['type']) ? $a['type'] : '',
            isset($b['type']) ? $b['type'] : ''
        );
    }