Save events.

        Args:
            state_change_identifier: Id of the state change that generate these events.
            events: List of Event objects.

def write_events(self, state_change_identifier, events, log_time):
        """ Save events.

        Args:
            state_change_identifier: Id of the state change that generate these events.
            events: List of Event objects.
        """
        events_data = [
            (None, state_change_identifier, log_time, self.serializer.serialize(event))
            for event in events
        ]
        return super().write_events(events_data)