@Override
  public void put(final int key, final int value) {
    final IntSet collection = myMap.get(key);
    if (collection == null) {
      final IntSet x = new IntOpenHashSet();
      x.add(value);
      myMap.put(key, x);
    }
    else {
      collection.add(value);
    }
  }
@Override
  public void put(final int key, final int value)