public class NotificationHandler : IAlertNotifyHandler {
    public bool OnNotification(SPAlertHandlerParams ahp) {
        var x = string.Empty;
        return false;
    }
}

<NotificationHandlerAssembly>
    AlertHandler, Version=1.0.0.0, Culture=neutral, PublicKeyToken=e7e8520342f474c1
</NotificationHandlerAssembly>
<NotificationHandlerClassName>
    AlertHandler.NotificationHandler
</NotificationHandlerClassName>