@Override
  Set<Integer> createUnfiltered(Iterable<Integer> contents) {
    return Sets.newHashSet(contents);
  }

  @Override
  Set<Integer> filter(Set<Integer> elements, Predicate<? super Integer> predicate) {
    return Sets.filter(elements, predicate);
  }

      @Override
      protected SortedSet<Integer> delegate() {
        return result;
      }
    };
  }

  @Override
  SortedSet<Integer> filter(SortedSet<Integer> elements, Predicate<? super Integer> predicate) {
    return Sets.filter(elements, predicate);
  }

      return emptySet();
    } else {
      return emptyList();
    }
  }

  @Override
  public void clear() {
    keySet().clear();
  }

  @Override
  Set<K> createKeySet() {
    return Sets.filter(unfiltered.keySet(), keyPredicate);
  }

  @Override
  public Collection<V> get(@ParametricNullness K key) {
    if (keyPredicate.apply(key)) {
      return unfiltered.get(key);

      return emptySet();
    } else {
      return emptyList();
    }
  }

  @Override
  public void clear() {
    keySet().clear();
  }

  @Override
  Set<K> createKeySet() {
    return Sets.filter(unfiltered.keySet(), keyPredicate);
  }

  @Override
  public Collection<V> get(@ParametricNullness K key) {
    if (keyPredicate.apply(key)) {
      return unfiltered.get(key);

  public Set<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {
    return (Set<V>) super.replaceValues(key, values);
  }

  @Override
  Set<Entry<K, V>> createEntries() {
    return Sets.filter(unfiltered().entries(), entryPredicate());
  }

  @Override
  public Set<Entry<K, V>> entries() {
    return (Set<Entry<K, V>>) super.entries();
  }

                          graph.predecessors(node).iterator(),
                          (N predecessor) -> EndpointPair.ordered(predecessor, node)),
                      Iterators.transform(
                          // filter out 'node' from successors (already covered by predecessors,
                          // above)
                          Sets.difference(graph.successors(node), ImmutableSet.of(node)).iterator(),

  public Set<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {
    return (Set<V>) super.replaceValues(key, values);
  }

  @Override
  Set<Entry<K, V>> createEntries() {
    return Sets.filter(unfiltered().entries(), entryPredicate());
  }

  @Override
  public Set<Entry<K, V>> entries() {
    return (Set<Entry<K, V>>) super.entries();
  }