docs: public static List<Collection<Integer>> sortHostIdByHGDistance(int hostId, Map<Integer, String> hostGroups) {
          String localHostGroup = hostGroups.get(hostId);
          Preconditions.checkArgument(localHostGroup != null);
  
          HAGroup localHaGroup = new HAGroup(localHostGroup);
  
          // Memorize the distance, map the distance to host ids.
          Multimap<Integer, Integer> distanceMap = MultimapBuilder.treeKeys(Comparator.<Integer>naturalOrder().reversed())
                  .arrayListValues().build();
          for (Map.Entry<Integer, String> entry : hostGroups.entrySet()) {
              if (hostId == entry.getKey()) {
                  continue;
              }
              distanceMap.put(localHaGroup.getRelationshipTo(entry.getValue()).m_distance, entry.getKey());
          }
  
          return new ArrayList<>(distanceMap.asMap().values());
      }