using System;

using System.Collections.Generic;

​

static class F

{

    public static void M<T>(this IEnumerable<T> enumeration, Action<T> action)

    {

        foreach (var o in enumeration)

            action(o);

    }

​

    public static void U(C.K d)

    {

        ((Dictionary<string, dynamic>)d).M(kvp => Console.WriteLine(kvp));

        M((Dictionary<string, dynamic>)d, kvp => Console.WriteLine(kvp));

    }

}

​

class C

{

    public class K : Dictionary<string, dynamic>

    {

    }

}

​

public class Program

{

    public static void Main()

    {

        var d = new C.K{{"a", 1}, {"b", 2}};

        F.U(d);

    }

}