previous = previous.previous;
      nextIndex--;
      return current;
    }

    @Override
    public int nextIndex() {
      return nextIndex;
    }

    @Override
    public int previousIndex() {
      return nextIndex - 1;
    }

    @Override
    public void set(Entry<K, V> e) {
      throw new UnsupportedOperationException();
    }

    @Override

            throw new NoSuchElementException();
          }
          canRemoveOrSet = true;
          return forwardIterator.next();
        }

        @Override
        public int previousIndex() {
          return nextIndex() - 1;
        }

        @Override
        public void remove() {
          checkRemove(canRemoveOrSet);
          forwardIterator.remove();

      }

      @Override
      public int nextIndex() {
        return getDelegateListIterator().nextIndex();
      }

      @Override
      public int previousIndex() {
        return getDelegateListIterator().previousIndex();
      }

      @Override
      public void set(@ParametricNullness V value) {
        getDelegateListIterator().set(value);
      }

      @Override

    }
    assertEquals(3, iterator.previousIndex());
    assertEquals("4", iterator.previous());
    assertEquals("3", iterator.previous());
    assertEquals("2", iterator.previous());
    assertTrue(iterator.hasPrevious());
    assertEquals("1", iterator.previous());
    assertFalse(iterator.hasPrevious());
    assertEquals(-1, iterator.previousIndex());
    try {
      iterator.previous();

    ListIterator<String> iterator = Iterators.emptyListIterator();
    assertFalse(iterator.hasNext());
    assertFalse(iterator.hasPrevious());
    assertEquals(0, iterator.nextIndex());
    assertEquals(-1, iterator.previousIndex());
    assertThrows(NoSuchElementException.class, () -> iterator.next());
    assertThrows(NoSuchElementException.class, () -> iterator.previous());