public function error( $message, $code = null, $data = null )
    {
        if ( null === $code && isset( $this->errorCodes[$message] ) )
        {
            $code = $this->errorCodes[$message];
        }

        return $this->getResponse( 'error', (object) array(
            'code'      => $code,
            'message'   => $message,
            'data'      => $data,
        ) );
    }