using System;

using System.ComponentModel;

public class Program

{

    public abstract class Base : INotifyPropertyChanged

    {

        public event PropertyChangedEventHandler PropertyChanged;

    }

    public partial class ImplBase : Base {

    }

    public partial class ImplBase {

        void someFunc(){

            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs("propName"));

        }

    }

    public static void Main()

    {

        Console.Out.WriteLine("done");

    }

}