def enforce_notifications(self, data):
        """
        Ensures that when an owner changes, default notifications are added for the new owner.
        Old owner notifications are retained unless explicitly removed.
        :param data:
        :return:
        """
        if data["owner"]:
            notification_name = "DEFAULT_{}".format(
                data["owner"].split("@")[0].upper()
            )
            data[
                "notifications"
            ] += notification_service.create_default_expiration_notifications(
                notification_name, [data["owner"]]
            )
        return data

        Ensures that when an owner changes, default notifications are added for the new owner.
        Old owner notifications are retained unless explicitly removed.
        :param data:
        :return:
        
lemur/pending_certificates/schemas.py