Instance is not bound to a Session (nameko-sentry DP)

[alexeysofin]

When using new interface inside some service method like this (taken from examples in README)

class Service(object):
    name = "service"

   db = Database(DeclarativeBase)
   sentry = SentryReporter()

    @entrypoint
    def write_to_db(self):
        model = Model(...)
        with self.db.get_session() as session:
            session.add(model)
            raise Exception()

if any exception is raised inside with block and service instance has nameko-sentry DP this will trigger
Instance <Model at 0x7fe4de51b240> is not bound to a Session when raven wants to stringify this object (repr wants instance's primary key) because the session is closed after context block is over.

Is there a reason to close a session in context manager?

Secondly there might be some misunderstanding from the documentation because it says

As a context manager that issues a commit or rollback on exit:

But not a word about that session is closed and all instances are invalidated.