[pygtk] problems with gtk.Notebook

[Tim Hoeppner]

I have a notebook with 4 tabs and i was first just working on the first
tab and everything was working great but once i started to create
content on a different tab i get this error:

assertion 'widget->parent == NULL' failed

i searched for it on google and found some possible useful information
for c but don't know how to use it in pygtk, here is the code they
suggested:

close_dialog () {
   gtk_widget_destroy(new_dialog);
   gtk_widget_destroyed(new_dialog, &new_dialog);
}