return ImmutableSet.copyOf(elements);
  }

  public void testCreation_allDuplicates() {
    ImmutableSet<String> set = ImmutableSet.copyOf(Lists.newArrayList("a", "a"));
    assertTrue(set instanceof SingletonImmutableSet);
    assertEquals(Lists.newArrayList("a"), new ArrayList<>(set));
  }

  public void testCreation_oneDuplicate() {
    // now we'll get the varargs overload

        }
        return sourceMap;
    }

    @Override
    protected void addFieldToSource(final Map<String, Object> sourceMap, final String field, final Object value) {
        if (value instanceof final LocalDateTime ldt) {
            final ZonedDateTime zdt = ZonedDateTime.of(ldt, ZoneId.systemDefault());
            super.addFieldToSource(sourceMap, field, DateTimeFormatter.ISO_INSTANT.format(zdt));
        } else {

            function.apply(reference),
            "the Function passed to Optional.transform() must not return null."));
  }

  @Override
  public boolean equals(@Nullable Object obj) {
    if (obj instanceof Present) {
      Present<?> other = (Present<?>) obj;
      return reference.equals(other.reference);
    }
    return false;
  }

  @Override
  public int hashCode() {

  }

  @Override
  public abstract boolean encloses(Range<C> otherRange);

  @Override
  public boolean equals(@Nullable Object obj) {
    if (obj == this) {
      return true;
    } else if (obj instanceof RangeSet) {
      RangeSet<?> other = (RangeSet<?>) obj;
      return this.asRanges().equals(other.asRanges());
    }
    return false;
  }

  @Override
  public final int hashCode() {

     * @param pattern
     *            The pattern string
     * @return The converted {@link Calendar}
     */
    public static Calendar toCalendar(final Object o, final String pattern) {
        if (o instanceof Calendar) {
            return (Calendar) o;
        }
        final java.util.Date date = DateConversionUtil.toDate(o, pattern);
        if (date != null) {
            final Calendar cal = Calendar.getInstance();

    if (o instanceof RangeMap) {
      RangeMap<?, ?> rangeMap = (RangeMap<?, ?>) o;
      return asMapOfRanges().equals(rangeMap.asMapOfRanges());
    }
    return false;
  }

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

  /**
   * This class is used to serialize ImmutableRangeMap instances. Serializes the {@link

    // targets.size() < size() / log(size())
    // TODO(kevinb): see if we can share code with OrderedIterator after it
    // graduates from labs.
    if (targets instanceof Multiset) {
      targets = ((Multiset<?>) targets).elementSet();
    }
    if (!SortedIterables.hasSameComparator(comparator(), targets) || (targets.size() <= 1)) {
      return super.containsAll(targets);
    }

    return absentFeatures;
  }

  @Override
  public boolean equals(@Nullable Object object) {
    if (object == this) {
      return true;
    }
    if (object instanceof TesterRequirements) {
      TesterRequirements that = (TesterRequirements) object;
      return this.presentFeatures.equals(that.presentFeatures)
          && this.absentFeatures.equals(that.absentFeatures);
    }

      }
    }
    return urls.build().toArray(new URL[0]);
  }

  /** Returns the URLs in the class path. */
  static URL[] getClassPathUrls() {
    return ClassPathUtil.class.getClassLoader() instanceof URLClassLoader
        ? ((URLClassLoader) ClassPathUtil.class.getClassLoader()).getURLs()
        : parseJavaClassPath();
  }

      // Overridden to prevent a ton of boxing
      return (target instanceof Float) && Floats.indexOf(array, (Float) target, start, end) != -1;
    }

    @Override
    public int indexOf(@Nullable Object target) {
      // Overridden to prevent a ton of boxing
      if (target instanceof Float) {
        int i = Floats.indexOf(array, (Float) target, start, end);
        if (i >= 0) {