docs: private List<Cluster<SubspaceModel>> sortClusters(Relation<V> relation, Object2ObjectMap<long[], List<ArrayModifiableDBIDs>> clustersMap) {
      final int db_dim = RelationUtil.dimensionality(relation);
      // int num = 1;
      List<Cluster<SubspaceModel>> clusters = new ArrayList<>();
      for(long[] pv : clustersMap.keySet()) {
        List<ArrayModifiableDBIDs> parallelClusters = clustersMap.get(pv);
        for(int i = 0; i < parallelClusters.size(); i++) {
          ArrayModifiableDBIDs c = parallelClusters.get(i);
          Cluster<SubspaceModel> cluster = new Cluster<>(c);
          cluster.setModel(new SubspaceModel(new Subspace(pv), Centroid.make(relation, c).getArrayRef()));
          String subspace = BitsUtil.toStringLow(cluster.getModel().getSubspace().getDimensions(), db_dim);
          cluster.setName(parallelClusters.size() > 1 ? ("Cluster_" + subspace + "_" + i) : ("Cluster_" + subspace));
          clusters.add(cluster);
        }
      }
  
      // sort the clusters w.r.t. lambda
      Comparator<Cluster<SubspaceModel>> comparator = new Comparator<Cluster<SubspaceModel>>() {
        @Override
        public int compare(Cluster<SubspaceModel> c1, Cluster<SubspaceModel> c2) {
          return c2.getModel().getSubspace().dimensionality() - c1.getModel().getSubspace().dimensionality();
        }
      };
      Collections.sort(clusters, comparator);
      return clusters;
    }