docs: public void save() throws FileNotFoundException {
      PrintStream p = new PrintStream(file);
      p.println(COMMENT_PREFIX + "Saved ELKI settings. First line is title, remaining lines are parameters.");
      for (Pair<String, ArrayList<String>> settings : store) {
        p.println(settings.first);
        for (String str : settings.second) {
          p.println(str);
        }
        p.println();
      }
      p.close();
    }