[pygtk] do_forall() and inheritance

[Paul Pogonyshev]

Hi,

I derive a custom container from gtk.VBox.  In it, I add a private
widget, so I need to override do_forall() to return it in case
`include_internals' is True.  How do I call the original method?
Calling gtk.VBox.do_forall() doesn't work:

  AttributeError: type object 'gtk.VBox' has no attribute 'do_forall'

and chain() works only for signal handlers.

Paul