public function sendError($error)
    {
        if (@ob_get_length()) {
            @ob_end_clean();
        }
        if ($error instanceof \Concrete\Core\Error\ErrorList\ErrorList) {
            $error->outputJSON();
        } else {
            header($_SERVER['SERVER_PROTOCOL'] . ' 400 Bad Request', true, 400);
            header('Content-Type: text/plain; charset=' . APP_CHARSET, true);
            echo($error instanceof Exception) ? $error->getMessage() : $error;
        }
        die();
    }