using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var callableMap = new Dictionary<string, Func<Instance>>

        {

            { "keyA", () => Instance.Old },

            { "keyB", () => Instance.New }

        };

        foreach(var mapEntry in callableMap){

            var result = mapEntry.Value();

            Console.WriteLine($"Calling with key {mapEntry.Key}, result {result}");

        }

    }

}

​

enum Instance{

    Old, New

}