public function executeSending( $subject, $body, $subscriber )
    {
        $email = $subscriber->attribute( 'email' );
        $parameters = array();
        $parameters['content_type'] = $this->emailContentType;
        $parameters['from'] = $this->emailFrom;
        $transport = eZNotificationTransport::instance( 'ezmail' );
        $result = $transport->send( array( $email ), $subject, $body, null, $parameters );
        if ( $result === false )
        {
            throw new Exception( 'Send email error! Subscriber id:' .$subscriber->attribute( 'id' ) );
        }
        eZDebugSetting::writeNotice( 'extension-ezcomments', "An email has been sent to '$email' (subject: $subject)", __METHOD__ );
    }