ImmutableSortedSet<Integer> set = ContiguousSet.create(Range.closed(1, 3), integers());
    assertFalse(set.contains(0));
    assertTrue(set.contains(1));
    assertTrue(set.contains(2));
    assertTrue(set.contains(3));
    assertFalse(set.contains(4));
    set = ContiguousSet.create(Range.open(0, 4), integers());
    assertFalse(set.contains(0));
    assertTrue(set.contains(1));
    assertTrue(set.contains(2));

   * set. The order in which these subsets appear in the outer set is undefined. Note that the power
   * set of the empty set is not the empty set, but a one-element set containing the empty set.
   *
   * <p>The returned set and its constituent sets use {@code equals} to decide whether two elements
   * are identical, even if the input set uses a different concept of equivalence.
   *

                  @Override
                  protected Set<String> create(String[] elements) {
                    Set<String> set = Sets.newHashSet("b", "c");
                    Set<String> other = Sets.newHashSet("a", "b", "c", "d");
                    return Sets.difference(set, other);
                  }
                })
            .named("set - superset")
            .withFeatures(

     * @return true if this set contains the specified element.
     */
    @Override
    public boolean contains(final Object o) {
        return map.containsKey(o);
    }

    /**
     * Adds the specified element to this set if it is not already present.
     *
     * @param o
     *            element to be added to this set.

func (set TargetIDSet) add(targetID TargetID) {
	set[targetID] = struct{}{}
}

// Union - returns union with given set as new set.
func (set TargetIDSet) Union(sset TargetIDSet) TargetIDSet {
	nset := set.Clone()

	for k := range sset {
		nset.add(k)
	}

	return nset
}

// Difference - returns difference with given set as new set.
func (set TargetIDSet) Difference(sset TargetIDSet) TargetIDSet {

        final Set<String> set = new HashSet<String>();
        traverser.forEach((ClassHandler) (packageName, shortClassName) -> set.add(ClassUtil.concatName(packageName, shortClassName)));
        assertThat(set.size() > 0, is(true));
        assertThat(set.contains(DummyTest.class.getName()), is(true));
        assertThat(set.contains(TraverserUtilTest.class.getName()), is(true));

  /**
   * Returns a {@link Set} whose methods throw {@link IllegalStateException} when the given node is
   * not present in this network.
   *
   * @since 33.1.0
   */
  protected final <T> Set<T> nodeInvalidatableSet(Set<T> set, N node) {
    return InvalidatableSet.of(
        set, () -> nodes().contains(node), () -> String.format(NODE_REMOVED_FROM_GRAPH, node));
  }

  /**

  }

  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);

  }

  public void testEmpty_comparator() {
    SortedSet<String> set = of();
    assertSame(Ordering.natural(), set.comparator());
  }

  public void testEmpty_headSet() {
    SortedSet<String> set = of();
    assertSame(set, set.headSet("c"));
  }

  public void testEmpty_tailSet() {
    SortedSet<String> set = of();
    assertSame(set, set.tailSet("f"));
  }

  public void testEmpty_subSet() {

        initialValue,
        getList().set(index, newValue));
    assertEquals("After set(i, x), get(i) should return x", newValue, getList().get(index));
    assertEquals("set() should not change the size of a list.", getNumElements(), getList().size());
  }

  @ListFeature.Require(SUPPORTS_SET)
  public void testSet_indexTooLow() {
    try {
      getList().set(-1, e3());