如何自定义嵌套类的创建？

Question

我正在尝试为具有嵌套成员的命令设置自定义。但是我的自定义无法正常工作。我究竟做错了什么？当我尝试创建实例时，出现错误，该月份必须介于1到12之间，这意味着未触发我的自定义。

        var fixture = new Fixture();

        fixture.Customize<CreatePaymentCardCommand.SourceCard>(
            obj =>
            {
                obj.With(x => x.ExpirationMonth, Random.Next(1, 12))
                   .With(x => x.ExpirationYear, DateTime.Now.AddYears(Random.Next(1, 3)).Year);

                return obj;
            });

        fixture.Customize<CreatePaymentCardCommand>(
            obj =>
            {
                obj.With(
                    x => x.Source,
                    () => new CreatePaymentCardCommand.Source()
                    {
                        Card = fixture.Create<CreatePaymentCardCommand.SourceCard>(),
                        Owner = fixture.Create<CreatePaymentCardCommand.Owner>(),
                        Id = fixture.Create<string>(),
                    });

                return obj;
            });

        var obj = fixture.Create<CreatePaymentCardCommand>();