class SwitchedVlanPropertiesAnswerer extends Answerer {

  @VisibleForTesting
  static void tryAddInterfaceToVlan(
      Map<Integer, ImmutableSet.Builder<NodeInterfacePair>> switchedVlanInterfaces,
      NodeInterfacePair iface,
      @Nullable Integer vlan,
      IntegerSpace vlans) {
    if (vlan != null && vlans.contains(vlan)) {
      switchedVlanInterfaces.computeIfAbsent(vlan, v -> ImmutableSet.builder()).add(iface);
    }
  }

  public  SwitchedVlanPropertiesAnswerer(Question question, IBatfish batfish);

}