public static <T extends @Nullable Object, S extends T> Comparator<Iterable<S>> lexicographical(
      Comparator<T> comparator) {
    return new LexicographicalOrdering<S>(checkNotNull(comparator));
  }

  /**
   * Returns {@code true} if each element in {@code iterable} after the first is greater than or
   * equal to the element that preceded it, according to the specified comparator. Note that this is

  public static <K, V> ImmutableSortedMap<K, V> copyOfSorted(SortedMap<K, ? extends V> map) {
    Comparator<? super K> comparator = map.comparator();
    if (comparator == null) {
      // If map has a null comparator, the keys should have a natural ordering,
      // even though K doesn't explicitly implement Comparable.
      comparator = (Comparator<? super K>) NATURAL_ORDER;
    }
    if (map instanceof ImmutableSortedMap) {

    @SuppressWarnings({"unchecked", "nullness"})
    Comparator<@Nullable Object> unsafeComparator = (Comparator<@Nullable Object>) comparator;
    return unsafeComparator.compare(a, b);
  }

  final transient Comparator<? super E> comparator;

  ImmutableSortedSet(Comparator<? super E> comparator) {
    this.comparator = comparator;
  }

  /**

          Comparator<? super E> comparator = spliterator.getComparator();
          if (comparator == null) {
            // A sorted spliterator with no comparator is already using natural order.
            // (We could probably find a way to avoid rawtypes here if we wanted.)
            @SuppressWarnings({"unchecked", "rawtypes"})
            Comparator<? super E> naturalOrder =

  }

  /**
   * Returned by get() when a missing key is provided. Also holds the comparator, if any, used for
   * values.
   */
  private final transient ImmutableSet<V> emptySet;

  ImmutableSetMultimap(
      ImmutableMap<K, ImmutableSet<V>> map,
      int size,
      @CheckForNull Comparator<? super V> valueComparator) {
    super(map, size);
    this.emptySet = emptySet(valueComparator);
  }

   * there is no need to use this method.
   *
   * @param comparator the comparator that defines the order
   * @return comparator itself if it is already an {@code Ordering}; otherwise an ordering that
   *     wraps that comparator
   */
  @GwtCompatible(serializable = true)
  public static <T extends @Nullable Object> Ordering<T> from(Comparator<T> comparator) {
    return (comparator instanceof Ordering)
        ? (Ordering<T>) comparator

      return standardTailSet(fromElement);
    }

    @SuppressWarnings("unchecked")
    @Override
    public Comparator<? super E> comparator() {
      Comparator<? super E> forwardComparator = forward.comparator();
      if (forwardComparator == null) {
        return (Comparator) Ordering.natural().reverse();
      } else {
        return reverse(forwardComparator);
      }
    }

   * @since 11.0
   */
  @DoNotMock
  public static final class Builder<R, C, V> {
    private final List<Cell<R, C, V>> cells = Lists.newArrayList();
    @CheckForNull private Comparator<? super R> rowComparator;
    @CheckForNull private Comparator<? super C> columnComparator;

    /**
     * Creates a new builder. The returned builder is equivalent to the builder generated by {@link
     * ImmutableTable#builder}.
     */

import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.AbstractMap;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.SortedMap;
import java.util.function.BinaryOperator;

   */
  public static <T extends @Nullable Object> Iterable<T> mergeSorted(
      final Iterable<? extends Iterable<? extends T>> iterables,
      final Comparator<? super T> comparator) {
    checkNotNull(iterables, "iterables");
    checkNotNull(comparator, "comparator");
    Iterable<T> iterable =
        new FluentIterable<T>() {
          @Override
          public Iterator<T> iterator() {