Comment 2 for bug 181833

So this is affecting Launchpad too. However, we think it's a pyscopg2 refcounting bug: it looks like the only way that self->proxy.proxy_object can be NULL is if the object has been deallocated (and so the traverse is accessing deallocated memory), and certainly if self->proxy.proxy_object can be NULL on a live proxy object then there are problems all over the module.