[TurboGears] how to recover from aborted transaction

[Soni Bergraj]

Hello,
I try to get a Subject from the database, if this fails i want to create
a new one. But how ever i arrange hub.begin(), hub.end() and
hub.commit() i always get an

AssertionError: This transaction has already gone through ROLLBACK;
begin another transaction

For the except statement (object does not exist, create a new one)

        hub.begin()
        try:
            subject     = Subject.byName(name)
            hub.commit
            hub.end()

        except SQLObjectNotFound:
            hub.end()
            hub.begin()
            subject     = Subject(name = name)
            hub.commit()
            hub.end()

The hub is of type PackageHub, I didn't found documentation for it
(deprecated?).

Thanks for help,

-- 
Soni Bergraj