func (connector *SIRIVehicleMonitoringSubscriptionBroadcaster) checkLines(vm *sxml.XMLVehicleMonitoringSubscriptionRequestEntry) (resources []*SubscribedResource, lineIds []string) {
    // check for subscription to all lines
    if len(vm.Lines()) == 0 {
        var lv []string
        //find all lines corresponding to the remoteCodeSpace