using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(Animal.ScreenName());

        Console.WriteLine(IListItem.ScreenName());

    }

}

​

public interface IListItem {

  static string ScreenName() => "IListItem";

}

​

public class Animal: IListItem {

    public static string ScreenName() => "Animal";

}

​

public class Mammal: IListItem {

}