class StartUp
    {
        static void Main(string[] args)
        {
            Worker1 w1 = new Worker1();
            Worker2 w2 = new Worker2();
            List<IWorker> myList = new List<IWorker>()
            {
                w1,
                w2
            };

            foreach (var item in myList)
            {
                item.DoSomething();
            }

            MyMethod(w1);
            MyMethod(w2);

        }


        public static void MyMethod(IWorker w)
        {
            w.DoSomething();
        }


    }

    public interface IWorker
    {
        void DoSomething();
    }

    public class Worker1 : IWorker
    {

        public void DoSomething()
        {
            Console.WriteLine("Method worker1");
        }

    }
    public class Worker2 : IWorker
    {

        public void DoSomething()
        {
            Console.WriteLine("Method worker2");
        }

    }