docs: public void dfs(CLIQUEUnit unit, ModifiableDBIDs cluster, CLIQUESubspace model) {
      cluster.addDBIDs(unit.getIds());
      unit.markAsAssigned();
      model.addDenseUnit(unit);
  
      final long[] dims = getDimensions();
      for(int dim = BitsUtil.nextSetBit(dims, 0); dim >= 0; dim = BitsUtil.nextSetBit(dims, dim + 1)) {
        CLIQUEUnit left = leftNeighbor(unit, dim);
        if(left != null && !left.isAssigned()) {
          dfs(left, cluster, model);
        }
  
        CLIQUEUnit right = rightNeighbor(unit, dim);
        if(right != null && !right.isAssigned()) {
          dfs(right, cluster, model);
        }
      }
    }