docs: @Override
    protected void integrityCheckParameters(RdKNNNode parent, int index) {
      super.integrityCheckParameters(parent, index);
      // test if knn distance is correctly set
      RdKNNEntry entry = parent.getEntry(index);
      double knnDistance = kNNDistance();
      if(entry.getKnnDistance() != knnDistance) {
        double soll = knnDistance;
        double ist = entry.getKnnDistance();
        throw new RuntimeException("Wrong knnDistance in node " + parent.getPageID() + " at index " + index + " (child " + entry + ")" + "\nsoll: " + soll + ",\n ist: " + ist);
      }
    }