}
      }
      return null;
    }

    @Override
    Iterator<Entry<Cut<C>, Range<C>>> entryIterator() {
      if (restriction.isEmpty()) {
        return Iterators.emptyIterator();
      }
      Iterator<Range<C>> completeRangeItr;
      if (lowerBoundWindow.upperBound.isLessThan(restriction.lowerBound)) {
        return Iterators.emptyIterator();

      }
    };
  }

  @Override
  public Iterator<EndpointPair<N>> incidentEdgeIterator(N thisNode) {
    checkNotNull(thisNode);

    Iterator<EndpointPair<N>> resultWithDoubleSelfLoop;
    if (orderedNodeConnections == null) {
      resultWithDoubleSelfLoop =
          Iterators.concat(
              Iterators.transform(
                  predecessors().iterator(),

      checkNotNull(c);
      boolean changed = false;
      Iterator<Map<C, V>> iterator = backingMap.values().iterator();
      while (iterator.hasNext()) {
        Map<C, V> map = iterator.next();
        // map.keySet().removeAll(c) can throw a NPE when map is a TreeMap with
        // natural ordering and c contains a null.
        if (Iterators.removeAll(map.keySet().iterator(), c)) {
          changed = true;

      checkNotNull(c);
      boolean changed = false;
      Iterator<Map<C, V>> iterator = backingMap.values().iterator();
      while (iterator.hasNext()) {
        Map<C, V> map = iterator.next();
        // map.keySet().removeAll(c) can throw a NPE when map is a TreeMap with
        // natural ordering and c contains a null.
        if (Iterators.removeAll(map.keySet().iterator(), c)) {
          changed = true;

      }
    };
  }

  @Override
  public Iterator<EndpointPair<N>> incidentEdgeIterator(N thisNode) {
    checkNotNull(thisNode);

    Iterator<EndpointPair<N>> resultWithDoubleSelfLoop;
    if (orderedNodeConnections == null) {
      resultWithDoubleSelfLoop =
          Iterators.concat(
              Iterators.transform(
                  predecessors().iterator(),

    }
  }

  /**
   * Verifies that an Iterator is unmodifiable.
   *
   * <p>This test only works with iterators that iterate over a finite set.
   */
  public static void assertIteratorIsUnmodifiable(Iterator<?> iterator) {
    while (iterator.hasNext()) {
      iterator.next();
      try {
        iterator.remove();
        fail("Remove on unmodifiable iterator succeeded");

      }
    }
    size--;
  }

  /** Removes all nodes for the specified key. */
  private void removeAllNodes(@ParametricNullness K key) {
    Iterators.clear(new ValueForKeyIterator(key));
  }

  /** An {@code Iterator} over all nodes. */
  private class NodeIterator implements ListIterator<Entry<K, V>> {
    int nextIndex;
    @CheckForNull Node<K, V> next;
    @CheckForNull Node<K, V> current;

    final Iterator<Entry<K, Collection<V>>> keyIterator;
    @CheckForNull K key;
    @CheckForNull Collection<V> collection;
    Iterator<V> valueIterator;

    Itr() {
      keyIterator = map.entrySet().iterator();
      key = null;
      collection = null;
      valueIterator = Iterators.emptyModifiableIterator();
    }

      }
    }
    size--;
  }

  /** Removes all nodes for the specified key. */
  private void removeAllNodes(@ParametricNullness K key) {
    Iterators.clear(new ValueForKeyIterator(key));
  }

  /** An {@code Iterator} over all nodes. */
  private class NodeIterator implements ListIterator<Entry<K, V>> {
    int nextIndex;
    @CheckForNull Node<K, V> next;
    @CheckForNull Node<K, V> current;

    final Iterator<Entry<K, Collection<V>>> keyIterator;
    @CheckForNull K key;
    @CheckForNull Collection<V> collection;
    Iterator<V> valueIterator;

    Itr() {
      keyIterator = map.entrySet().iterator();
      key = null;
      collection = null;
      valueIterator = Iterators.emptyModifiableIterator();
    }