c# - Add event across AppDomain

Question

Alright, so I have this python code

_events.GameStart += method

method():
    DoStuff

and on the c# side

[SecuritySafeCritical]
public class ScriptEvents: MarshalByRefObject
{
    public event Action GameStart;

    public ScriptEvents(Engine e)
    {
        _engine = e;
    }

    public void FireGameStart()
    {
        if(GameStart != null)
          GameStart.Invoke();
    }
}

So I pass in ScriptEvents as _events. This has worked fine for python calling methods like _events.FireGameStart(), but I can't attach to the event.

I end up getting an error saying the delegate can't be serialized. Now I've tried using CrossAppDomainDelegate and that doesn't seem to solve the problem.

I was wondering if there was some magical way to toss that delegate across the wall so that I can invoke it from the c# side and have the subsequent python code activate?

Also, in case it's relevant

var Events = new ScriptEvents();
AppDomain sandbox = CreateSandbox(forTesting);
var _engine = Python.CreateEngine(sandbox);
ScriptScope scope = _engine.CreateScope();
scope.SetVariable("_events",Events);
var _sponsor = new Sponsor();
var life = (ILease) RemotingServices.GetLifetimeService(Events);
life.Register(_sponsor);

private static AppDomain CreateSandbox(bool forTesting)
{
    var permissions = new PermissionSet(PermissionState.Unrestricted);
    var appinfo = new AppDomainSetup {ApplicationBase = AppDomain.CurrentDomain.BaseDirectory};
    return AppDomain.CreateDomain("Scripting sandbox", null, appinfo, permissions);
}