public function filter($value)
    {
        if ($this->encodingFormat !== null) {
            $firstChar = mb_substr($value, 0, 1, $this->encodingFormat);
            $rest = mb_substr($value, 1, null, $this->encodingFormat);
            return mb_strtoupper($firstChar, $this->encodingFormat) . $rest;
        }

        $firstChar = mb_substr($value, 0, 1);
        $rest = mb_substr($value, 1);

        return mb_strtoupper($firstChar) . $rest;
    }