}

      @Override
      Iterator<E> elementIterator() {
        throw new AssertionError("should never be called");
      }

      @Override
      Iterator<Entry<E>> entryIterator() {
        final Iterator<? extends Entry<? extends E>> iterator1 = multiset1.entrySet().iterator();
        final Iterator<? extends Entry<? extends E>> iterator2 = multiset2.entrySet().iterator();

      }

      @Override
      Iterator<E> elementIterator() {
        throw new AssertionError("should never be called");
      }

      @Override
      Iterator<Entry<E>> entryIterator() {
        final Iterator<? extends Entry<? extends E>> iterator1 = multiset1.entrySet().iterator();
        final Iterator<? extends Entry<? extends E>> iterator2 = multiset2.entrySet().iterator();

          CheckedDowncastToActualType<const Iterator>(&other)->iterator_;
    }

   private:
    Iterator(const Iterator& other)
          // The explicit constructor call suppresses a false warning
          // emitted by gcc when supplied with the -Wextra option.
        : ParamIteratorInterface<T>(),
          base_(other.base_),
          iterator_(other.iterator_) {}

          CheckedDowncastToActualType<const Iterator>(&other)->iterator_;
    }

   private:
    Iterator(const Iterator& other)
          // The explicit constructor call suppresses a false warning
          // emitted by gcc when supplied with the -Wextra option.
        : ParamIteratorInterface<T>(),
          base_(other.base_),
          iterator_(other.iterator_) {}

    checkNotNull(iterable);
    Iterators.checkNonnegative(position);
    if (iterable instanceof List) {
      List<? extends T> list = Lists.cast(iterable);
      return (position < list.size()) ? list.get(position) : defaultValue;
    } else {
      Iterator<? extends T> iterator = iterable.iterator();
      Iterators.advance(iterator, position);
      return Iterators.getNext(iterator, defaultValue);
    }
  }

    checkNotNull(iterable);
    Iterators.checkNonnegative(position);
    if (iterable instanceof List) {
      List<? extends T> list = Lists.cast(iterable);
      return (position < list.size()) ? list.get(position) : defaultValue;
    } else {
      Iterator<? extends T> iterator = iterable.iterator();
      Iterators.advance(iterator, position);
      return Iterators.getNext(iterator, defaultValue);
    }
  }

      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;

        }
      }
      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(),

      @Override
      public Iterator<T> iterator() {
        return Iterators.concat(
            /* lazily generate the iterators on each input only as needed */
            new AbstractIndexedListIterator<Iterator<? extends T>>(inputs.length) {
              @Override
              public Iterator<? extends T> get(int i) {
                return inputs[i].iterator();
              }
            });
      }