// All collections are immutable empty. So safe for any type parameter.
          .put(Iterator.class, ImmutableSet.of().iterator())
          .put(PeekingIterator.class, peekingIterator(ImmutableSet.of().iterator()))
          .put(ListIterator.class, ImmutableList.of().listIterator())
          .put(Iterable.class, ImmutableSet.of())
          .put(Collection.class, ImmutableList.of())

   *
   * <p>Some algorithms that operate on a {@code PredecessorsFunction} may produce undesired results
   * if the returned {@link Iterable} contains duplicate elements. Implementations of such
   * algorithms should document their behavior in the presence of duplicates.
   *
   * <p>The elements of the returned {@code Iterable} must each be:
   *
   * <ul>
   *   <li>Non-null

  /**
   * A sensible definition of {@link #pollFirstEntry} in terms of the {@code iterator} of {@code
   * entrySet}. If you override {@code entrySet}, you may wish to override {@code pollFirstEntry} to
   * forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardPollFirstEntry() {
    return Iterators.pollNext(entrySet().iterator());
  }

  @Override
  public @Nullable Entry<K, V> pollLastEntry() {

  /**
   * A sensible definition of {@link #pollFirstEntry} in terms of the {@code iterator} of {@code
   * entrySet}. If you override {@code entrySet}, you may wish to override {@code pollFirstEntry} to
   * forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardPollFirstEntry() {
    return Iterators.pollNext(entrySet().iterator());
  }

  @Override
  public @Nullable Entry<K, V> pollLastEntry() {

        return new RegularImmutableList<>(elementsWithoutTrailingNulls);
    }
  }

  ImmutableList() {}

  // This declaration is needed to make List.iterator() and
  // ImmutableCollection.iterator() consistent.
  @Override
  public UnmodifiableIterator<E> iterator() {
    return listIterator();
  }

  @Override
  public UnmodifiableListIterator<E> listIterator() {
    return listIterator(0);
  }

    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<Entry<K, V>> iterator = getMap().entrySet().iterator();
          putAll(MinimalCollection.of(e3(), e0()));
          iterator.next();
        });
  }

  @MapFeature.Require(absent = SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)

   * values} is a {@link Collection}. Otherwise it creates a {@link #builder} and uses {@link
   * Builder#addAll(Iterable)}, with all the performance implications associated with that.
   */
  public static ImmutableIntArray copyOf(Iterable<Integer> values) {
    if (values instanceof Collection) {
      return copyOf((Collection<Integer>) values);
    }
    return builder().addAll(values).build();

  }

  private static <T> List<T> defensiveCopy(T... array) {
    return defensiveCopy(Arrays.asList(array));
  }

  static <T> List<T> defensiveCopy(Iterable<T> iterable) {
    ArrayList<T> list = new ArrayList<>();
    for (T element : iterable) {
      list.add(checkNotNull(element));
    }
    return list;
  }

  private Predicates() {}

  }

  private final class AsMapOfRanges extends IteratorBasedAbstractMap<Range<K>, V> {

    final Iterable<Entry<Range<K>, V>> entryIterable;

    @SuppressWarnings("unchecked") // it's safe to upcast iterables
    AsMapOfRanges(Iterable<RangeMapEntry<K, V>> entryIterable) {
      this.entryIterable = (Iterable) entryIterable;
    }

    @Override
    public boolean containsKey(@Nullable Object key) {

      assertEmpty(list);
      throw new Error();
    } catch (AssertionFailedError expected) {
    }
    try {
      assertEmpty(
          new Iterable<String>() {
            @Override
            public Iterator<String> iterator() {
              return singleton("a").iterator();
            }
          });
      throw new Error();
    } catch (AssertionFailedError expected) {
    }
  }