* @param string the string representation of a {@code double} value
   * @return the floating point value represented by {@code string}, or {@code null} if {@code
   *     string} has a length of zero or cannot be parsed as a {@code double} value
   * @throws NullPointerException if {@code string} is {@code null}
   * @since 14.0
   */
  @GwtIncompatible // regular expressions
  @CheckForNull
  public static Double tryParse(String string) {

   * @param string the string representation of a {@code float} value
   * @return the floating point value represented by {@code string}, or {@code null} if {@code
   *     string} has a length of zero or cannot be parsed as a {@code float} value
   * @throws NullPointerException if {@code string} is {@code null}
   * @since 14.0
   */
  @GwtIncompatible // regular expressions
  @CheckForNull
  public static Float tryParse(String string) {

  @Override
  public UnmodifiableIterator<E> iterator() {
    return Iterators.unmodifiableIterator(delegate.iterator());
  }

  @Override
  public boolean contains(@Nullable Object object) {
    return object != null && delegate.contains(object);
  }

  @Override
  public boolean containsAll(Collection<?> targets) {
    return delegate.containsAll(targets);
  }

  @Override
  public int size() {

            return version1.compareTo(version2) <= 0 ? node1 : node2;
        } catch (OverConstrainedVersionException exception) {
            // TODO log message or throw exception?

            return null;
        }
    }

        assertThrows(Graph.CycleDetectedException.class, () -> graph.addEdge("a2", "a1"));
    }

    @Test
    public void testPerf() throws IOException {
        List<String[]> data = new ArrayList<>();
        String k = null;
        for (String line : Files.readAllLines(Paths.get("src/test/resources/dag.txt"))) {
            if (line.startsWith("\t")) {
                data.add(new String[] {k, line.trim()});
            } else {

                    "properties": {
                        "name": {"type": "string", "title": "Name"},
                        "description": {
                            "anyOf": [{"type": "string"}, {"type": "null"}],
                            "title": "Description",
                        },
                    },
                    "type": "object",
                    "required": ["name"],

                    "properties": {
                        "name": {"type": "string", "title": "Name"},
                        "description": {
                            "anyOf": [{"type": "string"}, {"type": "null"}],
                            "title": "Description",
                        },
                    },
                    "type": "object",
                    "required": ["name"],

      Collection<Subscriber> eventMethodsInListener = entry.getValue();

      CopyOnWriteArraySet<Subscriber> eventSubscribers = subscribers.get(eventType);

      if (eventSubscribers == null) {
        CopyOnWriteArraySet<Subscriber> newSet = new CopyOnWriteArraySet<>();
        eventSubscribers =
            MoreObjects.firstNonNull(subscribers.putIfAbsent(eventType, newSet), newSet);
      }

  protected void checkCanCreate() {
    if (subjectGenerator == null) {
      throw new IllegalStateException("Call using() before createTestSuite().");
    }
    if (name == null) {
      throw new IllegalStateException("Call named() before createTestSuite().");
    }
    if (features == null) {
      throw new IllegalStateException("Call withFeatures() before createTestSuite().");
    }
  }

 * according to the value ordering.
 *
 * <p>The multimap does not store duplicate key-value pairs. Adding a new key-value pair equal to an
 * existing key-value pair has no effect.
 *
 * <p>Null keys and values are permitted (provided, of course, that the respective comparators
 * support them). All optional multimap methods are supported, and all returned views are
 * modifiable.
 *