* representations and are not serializable.
   */
  public static <T extends @Nullable Object> Predicate<T> notNull() {
    return ObjectPredicate.NOT_NULL.withNarrowedType();
  }

  /**
   * Returns a predicate that evaluates to {@code true} if the given predicate evaluates to {@code
   * false}.
   *
   * <p><b>Discouraged:</b> Prefer using {@code predicate.negate()}.

   * representations and are not serializable.
   */
  public static <T extends @Nullable Object> Predicate<T> notNull() {
    return ObjectPredicate.NOT_NULL.withNarrowedType();
  }

  /**
   * Returns a predicate that evaluates to {@code true} if the given predicate evaluates to {@code
   * false}.
   *
   * <p><b>Discouraged:</b> Prefer using {@code predicate.negate()}.

    public void test_tryStartOperation_singleArg_delegatesToTwoArg() {
        // tryStartOperation(name) should delegate to tryStartOperation(name, null)
        final AtomicReference<String> passedData = new AtomicReference<>("NOT_NULL");
        final CoordinatorHelper helper = new CoordinatorHelper() {
            @Override
            public boolean tryStartOperation(final String operationName, final String data) {
                passedData.set(data);