@Override
    public String getAlertFilter() {
        DriverHandler handler = handler();
        NetconfController controller = handler.get(NetconfController.class);
        MastershipService mastershipService = handler.get(MastershipService.class);
        DeviceId ncDeviceId = handler.data().deviceId();
        checkNotNull(controller, "Netconf controller is null");
        String reply = null;

        if (!mastershipService.isLocalMaster(ncDeviceId)) {
            log.warn("Not master for {} Use {} to execute command",
                     ncDeviceId,
                     mastershipService.getMasterFor(ncDeviceId));
            return null;
        }

        try {
            StringBuilder request = new StringBuilder();
            request.append(VOLT_NE_OPEN + VOLT_NE_NAMESPACE);
            request.append(ANGLE_RIGHT + NEW_LINE);
            request.append(buildStartTag(VOLT_ALERTS))
                .append(buildEmptyTag(ALERT_FILTER))
                .append(buildEndTag(VOLT_ALERTS))
                .append(VOLT_NE_CLOSE);

            reply = controller
                    .getDevicesMap()
                    .get(ncDeviceId)
                    .getSession()
                    .get(request.toString(), REPORT_ALL);
        } catch (NetconfException e) {
            log.error("Cannot communicate to device {} exception {}", ncDeviceId, e);
        }
        return reply;
    }
@Test
    public void testGetAlertFilter() throws Exception {
        voltConfig.getAlertFilter();
    }