return optional.orElse(null);
  }

  /**
   * Returns the minimum of the two values. If the values compare as 0, the first is returned.
   *
   * <p>The recommended solution for finding the {@code minimum} of some values depends on the type
   * of your data and the number of elements you have. Read more in the Guava User Guide article on

        }
        final int[] values = new int[2];
        values[0] = Integer.parseInt(froms[0]);
        if (values[0] < 0 || values[0] > 23) {
            throw new FessSystemException("Invalid hour value: " + values[0] + " in time: " + time + ". Hour must be between 0 and 23");
        }
        values[1] = Integer.parseInt(froms[1]);
        if (values[1] < 0 || values[1] > 59) {

      SampleElements<Entry<K, V>> mapEntries(SampleElements<K> keys, SampleElements<V> values) {
    return new SampleElements<>(
        mapEntry(keys.e0(), values.e0()),
        mapEntry(keys.e1(), values.e1()),
        mapEntry(keys.e2(), values.e2()),
        mapEntry(keys.e3(), values.e3()),
        mapEntry(keys.e4(), values.e4()));
  }

  public E e0() {
    return e0;
  }

  public E e1() {

      Collection<Object> values = cache.asMap().values();
      List<Entry<Object, Object>> warmed = warmUp(cache);

      Collection<Object> expected = new HashMap<>(cache.asMap()).values();
      assertThat(values).containsExactlyElementsIn(expected);
      assertThat(values.toArray()).asList().containsExactlyElementsIn(expected);

  /**
   * Returns a {@link Collector} that accumulates elements into an {@code ImmutableBiMap} whose keys
   * and values are the result of applying the provided mapping functions to the input elements.
   * Entries appear in the result {@code ImmutableBiMap} in encounter order.
   *
   * <p>If the mapped keys or values contain duplicates (according to {@link
   * Object#equals(Object)}), an {@code IllegalArgumentException} is thrown when the collection

  /**
   * Returns a {@link Collector} that accumulates elements into an {@code ImmutableBiMap} whose keys
   * and values are the result of applying the provided mapping functions to the input elements.
   * Entries appear in the result {@code ImmutableBiMap} in encounter order.
   *
   * <p>If the mapped keys or values contain duplicates (according to {@link
   * Object#equals(Object)}), an {@code IllegalArgumentException} is thrown when the collection

    }
  }

  @LazyInit private transient @Nullable Collection<V> values;

  @Override
  public Collection<V> values() {
    Collection<V> result = values;
    return (result == null) ? values = createValues() : result;
  }

  Collection<V> createValues() {
    return new Values();
  }

  Iterator<V> valuesIterator() {

    checkNotNull(values);
    if (values instanceof SortedSet) {
      SortedSet<C> set = (SortedSet<C>) values;
      Comparator<?> comparator = set.comparator();
      if (Ordering.<C>natural().equals(comparator) || comparator == null) {
        return closed(set.first(), set.last());
      }
    }
    Iterator<C> valueIterator = values.iterator();
    C min = checkNotNull(valueIterator.next());

    // forward map ordered by currency (even for country values)
    assertThat(bimap.values()).containsExactly(Country.CANADA, Country.CHILE).inOrder();
    // backward map ordered by country
    assertThat(bimap.inverse().keySet()).containsExactly(Country.CANADA, Country.CHILE).inOrder();
    // backward map ordered by country (even for currency values)
    assertThat(bimap.inverse().values()).containsExactly(Currency.DOLLAR, Currency.PESO).inOrder();

    keyIterator.next();
    keyIterator.remove();
    assertFalse(underlying.containsKey("c"));

    Collection<String> values = map.values();
    values.remove("4");
    assertFalse(underlying.containsKey("d"));

    Iterator<String> valueIterator = values.iterator();
    valueIterator.next();
    valueIterator.remove();
    assertFalse(underlying.containsKey("e"));