private function purgeNonceWord(string $key, array $word, int $stop_nonce, array &$new_nonce_list)
    {
        foreach ($word as $nonce) {
            if ($nonce['time'] >= $stop_nonce) {
                if (!array_key_exists($key, $new_nonce_list)) {
                    $new_nonce_list[$key] = array();
                }
                $new_nonce_list[$key][] = $nonce;
            }
        }
    }