How to call event of interface

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

  public delegate void xyz(string str);

   public class Test

   {

       public event xyz Notify;

       public void NotifyNow()

       {

           OnNotify();

       }

       void OnNotify()

       {

           if (Notify != null) Notify("amit");

       }

   }

    class Program

    {

        static void Main()

        {

            Test test = new Test();

            test.Notify += new xyz(test_Notify);

            test.NotifyNow();         

            Console.ReadLine();

        }

        static void test_Notify(string str)

        {

            Console.WriteLine("Notified xyz---" + str);

        }

    }