@GwtIncompatible // SerializableTester
  public void testStringConverterSerialization() {
    SerializableTester.reserializeAndAssert(Ints.stringConverter());
  }

  public void testToArray() {
    // need explicit type parameter to avoid javac warning!?
    List<Integer> none = Arrays.<Integer>asList();
    assertThat(Ints.toArray(none)).isEqualTo(EMPTY);

    List<Integer> one = Arrays.asList((int) 1);

   * user-created objects that aren't accessible via this range set's methods. This is generally
   * used to determine whether {@code copyOf} implementations should make an explicit copy to avoid
   * memory leaks.
   */
  boolean isPartialView() {
    return ranges.isPartialView();
  }

  /** Returns a new builder for an immutable range set. */

I think `Union[SomeType, None]` is more explicit about what it means.

It's just about the words and names. But those words can affect how you and your teammates think about the code.

As an example, let's take this function:

        // whether we are working on a transitive dependency or not. This
        // allows depMgmt to always override transitive dependencies, while
        // explicit child override depMgmt (viz. depMgmt should only
        // provide defaults to children, but should override transitives).
        // We can do this by calling isChildOfRootNode on the current node.

            return "url=" + url + " depth=" + depth;
        }
    }

    /**
     * Determines the maximum number of URLs to access during crawling.
     * This method checks for explicit max_access_count parameter or recursive flag.
     *
     * @param paramMap the data store parameters
     * @param dataMap the data map containing crawling configuration

  /**
   * Returns true if the given member is a method that overrides {@link Object#equals(Object)}.
   *
   * <p>The documentation for {@link Object#equals} says it should accept null, so don't require an
   * explicit {@code @NullableDecl} annotation (see <a
   * href="https://github.com/google/guava/issues/1819">#1819</a>).
   *
   * <p>It is not necessary to consider visibility, return type, or type parameter declarations. The

   * user-created objects that aren't accessible via this multimap's methods. This is generally used
   * to determine whether {@code copyOf} implementations should make an explicit copy to avoid
   * memory leaks.
   */
  boolean isPartialView() {
    return map.isPartialView();
  }

  // accessors

  @Override
  public boolean containsKey(@Nullable Object key) {

	if errCode != ErrNone {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(errCode), r.URL)
		return
	}

	if len(fanOutEntries) > 0 {
		// Once signature is validated, check if the user has
		// explicit permissions for the user.
		if !globalIAMSys.IsAllowed(policy.Args{
			AccountName:     cred.AccessKey,
			Groups:          cred.Groups,
			Action:          policy.PutObjectFanOutAction,

    nums.add(3);
    Predicate<Integer> isThree = Predicates.in(nums);
    assertFalse(isThree.apply(3));
  }

  /*
   * Tests that compilation will work when applying explicit types.
   */
  @SuppressWarnings("unused") // compilation test
  public void testIn_compilesWithExplicitSupertype() {
    Collection<Number> nums = ImmutableSet.of();
    Predicate<Number> p1 = Predicates.in(nums);

        3,
        3,
        7,
        new boolean[] {false, true, false, false, true, false, true});
  }

  public void testToArray() {
    // need explicit type parameter to avoid javac warning!?
    List<Boolean> none = Arrays.<Boolean>asList();
    assertThat(Booleans.toArray(none)).isEqualTo(EMPTY);

    List<Boolean> one = Arrays.asList(false);