public function getResponseClass($statusCode)
    {
        $responseClass = [
            1 => self::CLASS_INFORMATIONAL,
            2 => self::CLASS_SUCCESS,
            3 => self::CLASS_REDIRECTION,
            4 => self::CLASS_CLIENT_ERROR,
            5 => self::CLASS_SERVER_ERROR,
        ];

        $statusCode = $this->filterStatusCode($statusCode);

        return $responseClass[(int) substr($statusCode, 0, 1)];
    }