public static function sendJSONGrade($grade, $comment, $result_url, $key_key, $secret, &$debug_log=false, $signature=false) {
        global $LastJSONGradeResponse;
        $LastJSONGradeResponse = false;

        $content_type = "application/vnd.ims.lis.v2.result+json";

        if ( is_array($debug_log) ) $debug_log[] = array('Sending '.$grade.' to result_url='.$result_url);

        $addStructureRequest = self::getResultJSON($grade, $comment);

        $postBody = self::jsonIndent(json_encode($addStructureRequest));
        if ( is_array($debug_log) )  $debug_log[] = array('Grade JSON Request',$postBody);

        $more_headers = false;
        $response = self::sendOAuthBody("PUT", $result_url, $key_key,
            $secret, $content_type, $postBody, $more_headers, $signature);

        if ( is_array($debug_log) )  $debug_log[] = array('Grade JSON Response',$response);

        global $LastOAuthBodyBaseString;
        $lbs = $LastOAuthBodyBaseString;
        if ( is_array($debug_log) )  $debug_log[] = array('Our base string',$lbs);

        // TODO: Be smarter about this :)
        return true;
    }