Comment 25 for bug 1538471

One last comment: I tried downloading upstream pygobject 3.20.0 (which was released two days ago), and the scopes run fine using the Xenial typelib.

So I think the underlying problem is that we've got a problem of version skew, with the versions of gobject-introspection and pygobject currently in Xenial being incompatible. We either need to downgrade gobject-introspection (and rebuild typelibs for any affected packages), or upgrade pygobject.