implements SortedSet<E> {

    FilteredSortedSet(SortedSet<E> unfiltered, Predicate<? super E> predicate) {
      super(unfiltered, predicate);
    }

    @Override
    @CheckForNull
    public Comparator<? super E> comparator() {
      return ((SortedSet<E>) unfiltered).comparator();
    }

    @Override

    }

    @Override
    public SortedSet<V> get(@ParametricNullness K key) {
      return Collections.unmodifiableSortedSet(delegate().get(key));
    }

    @Override
    public SortedSet<V> removeAll(@CheckForNull Object key) {
      throw new UnsupportedOperationException();
    }

    @Override
    public SortedSet<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {

   * <p>This method is safe to use even when {@code sortedSet} is a synchronized or concurrent
   * collection that is currently being modified by another thread.
   *
   * @throws NullPointerException if {@code sortedSet} or any of its elements is null
   */
  public static <E> ImmutableSortedSet<E> copyOfSorted(SortedSet<E> sortedSet) {
    Comparator<? super E> comparator = SortedIterables.comparator(sortedSet);

      return (SortedMap<K, V>) unfiltered;
    }

    @Override
    public SortedSet<K> keySet() {
      return (SortedSet<K>) super.keySet();
    }

    @Override
    SortedSet<K> createKeySet() {
      return new SortedKeySet();
    }

    @WeakOuter
    class SortedKeySet extends KeySet implements SortedSet<K> {
      @Override
      @CheckForNull

import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.Set;
import java.util.SortedSet;
import java.util.stream.Collector;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**