Device component - ACTN Driver:

            subpath_url = self._subpath_root

        else:

            subpath_url = self._subpath_item.format(etht_service_name=etht_service_name)

        data = self._rest_conf_client.get(subpath_url)

        if not isinstance(data, dict): raise ValueError('data should be a dict')

        if 'ietf-eth-tran-service:etht-svc' not in data:

            raise ValueError('data does not contain key "ietf-eth-tran-service:etht-svc"')

        if 'ietf-eth-tran-service:etht-svc' not in data: return list()

        data = data['ietf-eth-tran-service:etht-svc']

        if 'etht-svc-instances' not in data:

            raise ValueError('data["ietf-eth-tran-service:etht-svc"] does not contain key "etht-svc-instances"')