Pass values throught InvokeEvent callback

Hi Andras,
just a quick question: I would like to pass a string or an vtk_object to the callback.
At the moment only a simple integer has been sent as value.
I tried to use VTK_STRING but the program unexpectedly exited (so I think an error has accured).

I really can’t figure out why is not working.
I just substituted the @vtk.calldata_type(vtk.VTK_LONG) with @vtk.calldata_type(vtk.VTK_STRING).
Is there something wrong here?

Thanks,
Ennio