protected function verifyErrorFormat($body, $httpStatusCode)
    {
        if (is_array($body) === false)
        {
            $this->throwServerError($body, $httpStatusCode);
        }

        if ((isset($body['error']) === false) or
            (isset($body['error']['code']) === false))
        {
            $this->throwServerError($body, $httpStatusCode);
        }

        $code = $body['error']['code'];

        if (Errors\ErrorCode::exists($code) === false)
        {
            $this->throwServerError($body, $httpStatusCode);
        }
    }