using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("A null object:");

        IsValueYes(null);

        Console.WriteLine("\nAn object initialized with Yes:");

        IsValueYes(new Wrapper { value = AnEnum.Yes });

        Console.WriteLine("\nAn object initialized with No:");

        IsValueYes(new Wrapper { value = AnEnum.No });

    }

    public static void IsValueYes(Wrapper item)

    {

        if (item?.value == AnEnum.Yes)

        {

            Console.WriteLine("The value is Yes.");

        }

        else

        {

            Console.WriteLine("The value is not Yes.");

        }

    }       

    public enum AnEnum

    {

        Yes,

        No

    }

    public class Wrapper

    {

        public AnEnum value { get; set; }

    }

}