Method _after_attach

lib/sqlalchemy/orm/session.py:4287–4296

(self, state: InstanceState[Any], obj: object)

        return True

    def _after_attach(self, state: InstanceState[Any], obj: object) -> None:
        state.session_id = self.hash_key
        if state.modified and state._strong_obj is None:
            state._strong_obj = obj
        self.dispatch.after_attach(self, state)

        if state.key:
            self.dispatch.detached_to_persistent(self, state)
        else:
            self.dispatch.transient_to_pending(self, state)

    def __contains__(self, instance: object) -> bool:
        """Return True if the instance is associated with this session.