}

  public void testPowerSetShowOff() {
    Set<Object> zero = ImmutableSet.of();
    Set<Set<Object>> one = powerSet(zero);
    Set<Set<Set<Object>>> two = powerSet(one);
    Set<Set<Set<Set<Object>>>> four = powerSet(two);
    Set<Set<Set<Set<Set<Object>>>>> sixteen = powerSet(four);
    Set<Set<Set<Set<Set<Set<Object>>>>>> sixtyFiveThousandish = powerSet(sixteen);

    Set<String> set = of("a", "b");
    assertEquals(Sets.newHashSet("a", "b"), set);
  }

  public void testCreation_threeElements() {
    Set<String> set = of("a", "b", "c");
    assertEquals(Sets.newHashSet("a", "b", "c"), set);
  }

  public void testCreation_fourElements() {
    Set<String> set = of("a", "b", "c", "d");
    assertEquals(Sets.newHashSet("a", "b", "c", "d"), set);
  }

    Set<String> set = of("a", "b");
    assertEquals(Sets.newHashSet("a", "b"), set);
  }

  public void testCreation_threeElements() {
    Set<String> set = of("a", "b", "c");
    assertEquals(Sets.newHashSet("a", "b", "c"), set);
  }

  public void testCreation_fourElements() {
    Set<String> set = of("a", "b", "c", "d");
    assertEquals(Sets.newHashSet("a", "b", "c", "d"), set);
  }

    public Iterable<E> order(List<E> insertionOrder) {
      return gen.order(insertionOrder);
    }
  }

  private static Set<Feature<?>> computeReserializedCollectionFeatures(Set<Feature<?>> features) {
    Set<Feature<?>> derivedFeatures = new HashSet<>(features);
    derivedFeatures.remove(SERIALIZABLE);
    derivedFeatures.remove(SERIALIZABLE_INCLUDING_VIEWS);
    return derivedFeatures;
  }

      @SuppressWarnings("unchecked") // The natural-ordered empty set supports all types.
      RegularImmutableSortedSet<E> result =
          (RegularImmutableSortedSet<E>) RegularImmutableSortedSet.NATURAL_EMPTY_SET;
      return result;
    } else {
      return new RegularImmutableSortedSet<>(ImmutableList.of(), comparator);
    }
  }

  /**
   * Returns the empty immutable sorted set.
   *

    set.clear();
    assertTrue(set.isEmpty());
    assertEquals(Collections.singleton("bar"), sortedTable.rowKeySet());
  }

  public void testRowKeySetSubSet() {
    sortedTable = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c', "dog", 2, 'd');
    Set<String> set = sortedTable.rowKeySet().subSet("cat", "egg");
    assertEquals(Collections.singleton("dog"), set);
    set.clear();

   * </ol>
   *
   * @param set the presumed-immutable set
   * @param sampleElement an element of the same type as that contained by {@code set}. {@code set}
   *     may or may not have {@code sampleElement} as a member.
   */
  public static <E extends @Nullable Object> void assertSetIsUnmodifiable(
      Set<E> set, E sampleElement) {
    assertCollectionIsUnmodifiable(set, sampleElement);
  }

  /**

import java.util.Comparator;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Set;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An immutable sorted set with one or more elements. TODO(jlevy): Consider separate class for a
 * single-element sorted set.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */

    }

    @LazyInit @CheckForNull transient Set<E> elementSet;

    Set<E> createElementSet() {
      return Collections.<E>unmodifiableSet(delegate.elementSet());
    }

    @Override
    public Set<E> elementSet() {
      Set<E> es = elementSet;
      return (es == null) ? elementSet = createElementSet() : es;
    }

    @LazyInit @CheckForNull transient Set<Multiset.Entry<E>> entrySet;

      K key = entry.getKey();
      Collection<? extends V> values = entry.getValue();
      ImmutableSet<V> set = valueSet(valueComparator, values);
      if (!set.isEmpty()) {
        builder.put(key, set);
        size += set.size();
      }
    }

    return new ImmutableSetMultimap<>(builder.buildOrThrow(), size, valueComparator);
  }

  /**