@Override
        public Iterator<IdIndexEntry> iterator() {
          return new Iterator<>() {
            final IntIterator myIterator = myOccurrences.keySet().iterator();

            @Override
            public boolean hasNext() {
              return myIterator.hasNext();
            }

            @Override
            public IdIndexEntry next() {
              return new IdIndexEntry(myIterator.nextInt());
            }
          };
        }
@Override
        public Iterator<IdIndexEntry> iterator()