Can't operate on closed transaction inside context manager. Please complete the context manager before emitting further commands.

Raise code

tImplementedError()

    @classmethod
    def _trans_ctx_check(cls, subject):
        trans_context = subject._trans_context_manager
        if trans_context:
            if not trans_context._transaction_is_active():
                raise exc.InvalidRequestError(
                    "Can't operate on closed transaction inside context "
                    "manager.  Please complete the context manager "
                    "before emitting further commands."
                )

    def __enter__(self):
        subject = self._get_subject()

        # none