* @since 13.0
   */
  void addListener(Listener listener, Executor executor);

  /**
   * The lifecycle states of a service.
   *
   * <p>The ordering of the {@link State} enum is defined such that if there is a state transition
   * from {@code A -> B} then {@code A.compareTo(B) < 0}. N.B. The converse is not true, i.e. if

   * add(Object)} call will throw a {@code ClassCastException}.
   *
   * <p>The type specification is {@code <E extends Comparable>}, instead of the more specific
   * {@code <E extends Comparable<? super E>>}, to support classes defined without generics.
   */
  @SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
  public static <E extends Comparable> TreeMultiset<E> create() {
    return new TreeMultiset<>(Ordering.natural());
  }

---

Hier ist, was Sie beachten sollten und wie Sie einen Pull Request überprüfen:

### Das Problem verstehen

* Stellen Sie zunächst sicher, dass Sie **das Problem verstehen**, welches der Pull Request zu lösen versucht. Möglicherweise gibt es eine längere Diskussion dazu in einer GitHub-Diskussion oder einem GitHub-Issue.

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