this.arithmetic = arithmetic;
    }

    @Override
    public int add(int a, int b) {
      return arithmetic.add(a, b);
    }

    @Override
    public int minus(int a, int b) {
      return arithmetic.minus(a, b);
    }

    @Override
    public String toString() {
      return arithmetic.toString();
    }
  }

   * Returns an immutable set containing the given elements, minus duplicates, in the order each was
   * first specified. That is, if multiple elements are {@linkplain Object#equals equal}, all except
   * the first are ignored.
   */
  public static <E> ImmutableSet<E> of(E e1, E e2) {
    return construct(2, e1, e2);
  }

  /**
   * Returns an immutable set containing the given elements, minus duplicates, in the order each was

              return roundCeilingAsDouble;
            }
            roundFloor = toX(roundFloorAsDouble, RoundingMode.FLOOR);
          }

          X deltaToFloor = minus(x, roundFloor);
          X deltaToCeiling = minus(roundCeiling, x);
          int diff = deltaToFloor.compareTo(deltaToCeiling);
          if (diff < 0) { // closer to floor
            return roundFloorAsDouble;

  @Override
  protected Map<String, Integer> makePopulatedMap() {
    return ImmutableMap.of("one", 1);
  }

  @Override
  protected String getKeyNotInPopulatedMap() {
    return "minus one";
  }

  @Override
  protected Integer getValueNotInPopulatedMap() {
    return -1;
  }

  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    return ImmutableSortedMap.of("one", 1);
  }

  @Override
  protected String getKeyNotInPopulatedMap() {
    return "minus one";
  }

  @Override
  protected Integer getValueNotInPopulatedMap() {
    return -1;
  }

  protected Map<String, Integer> makePopulatedMap() {
    return SerializableTester.reserialize(ImmutableMap.of("one", 1, "two", 2, "three", 3));
  }

  @Override
  protected String getKeyNotInPopulatedMap() {
    return "minus one";
  }

  @Override
  protected Integer getValueNotInPopulatedMap() {
    return -1;
  }

    public static final char DOUBLE_VERTICAL_LINE = '\u2016';

    /** PARALLEL TO */
    public static final char PARALLEL_TO = '\u2225';

    /** MINUS SIGN */
    public static final char MINUS_SIGN = '\u2212';

    /** FULLWIDTH HYPHEN-MINUS */
    public static final char FULLWIDTH_HYPHEN_MINUS = '\uFF0D';

    /** CENT SIGN */
    public static final char CENT_SIGN = '\u00A2';

    sortedMap.put("two", 2);
    sortedMap.put("three", 3);
    return sortedMap;
  }

  @Override
  protected String getKeyNotInPopulatedMap() throws UnsupportedOperationException {
    return "minus one";
  }

  @Override
  protected Integer getValueNotInPopulatedMap() throws UnsupportedOperationException {
    return -1;
  }

  @Override
  protected SortedMap<String, Integer> makePopulatedMap() {
    return ImmutableSortedMap.of("one", 1, "two", 2, "three", 3);
  }

  @Override
  protected String getKeyNotInPopulatedMap() {
    return "minus one";
  }

  @Override
  protected Integer getValueNotInPopulatedMap() {
    return -1;
  }

   * given collection in the order returned by the collection's iterator.
   *
   * @param collection the elements that the set should contain
   * @return a new {@code CompactLinkedHashSet} containing those elements (minus duplicates)
   */
  public static <E extends @Nullable Object> CompactLinkedHashSet<E> create(
      Collection<? extends E> collection) {
    CompactLinkedHashSet<E> set = createWithExpectedSize(collection.size());