using static System.Console;

using System.Collections.Generic;                   

public class Program {

    public static void Main() {

        ImprimeValores(null);

        ImprimeValores(new List<int>());

        ImprimeValores(new List<int> { 1, 2, 3 });

    }

    static void ImprimeValores(IList<int> values) {

        if (values != null) foreach(int v in values) WriteLine("value:" + v);

    }

}