docs: private int max(Map<Integer, ModifiableDBIDs> candidates) {
      int maxDim = -1, size = -1;
      for(Integer nextDim : candidates.keySet()) {
        int nextSet = candidates.get(nextDim).size();
        if(size < nextSet) {
          size = nextSet;
          maxDim = nextDim;
        }
      }
      return maxDim;
    }