class IpOwners {

  @VisibleForTesting
  static Map<Ip, Map<String, Set<String>>> computeIpVrfOwners(
      Map<Ip, Map<String, Map<String, Set<String>>>> ipVrfIfaceOwners) {
    return toImmutableMap(
        ipVrfIfaceOwners,
        Entry::getKey, /* Ip */
        ipEntry ->
            toImmutableMap(
                ipEntry.getValue(),
                Entry::getKey, /* Hostname */
                nodeEntry -> ImmutableSet.copyOf(nodeEntry.getValue().keySet()))); /* VRFs */
  }

  public  IpOwners(Map<String, Configuration> configurations);

}