using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        Guid? y = Guid.NewGuid();

        Guid? z = null;

        var arrayOfGuids = new Guid[10];

        Console.WriteLine(arrayOfGuids.Contains(y.Value));

        Console.WriteLine(arrayOfGuids.Contains(z.Value));

    }

}