private final ConcurrentHashMultiset<?> z;

    ContainsBothWithContainsMultisetFirst(ContainsMultiset a, ConcurrentHashMultiset<?> z) {
      this.a = a;
      this.z = z;
    }
  }

  public void testCreate() {
    ConcurrentHashMultiset<Integer> multiset = ConcurrentHashMultiset.create();
    assertTrue(multiset.isEmpty());
    reserializeAndAssert(multiset);
  }

  public void testCreateFromIterable() {