code: public List<E> getBetterOrEqual(int threshold) {
  
      List<E> bests = new ArrayList<>();
      for (E element : this.map.keySet()) {
        Ranking ranking = this.map.get(element);
        if ((ranking != null) && (ranking.rank >= threshold)) {
          bests.add(element);
        }
      }
      return bests;
    }
docs: This method gets all elements with a {@link #getRank(Object) rank} greater or equal to the given {@code threshold}.
  
  @param threshold is the minimum accepted {@link #getRank(Object) rank}.
  @return the list with all elements better or equal to the given {@code threshold}.