public function npgettext($msgctxt, $msgid, $msgidPlural, $number)
    {
        $key = implode(chr(4), [$msgctxt, $msgid]);
        $ret = $this->ngettext($key, $msgidPlural, $number);
        if (strpos($ret, chr(4)) !== false) {
            return $msgid;
        }

        return $ret;
    }