using System.Collections.Generic;
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var x  = new List<int>{ 1, 2};
            var y = x.Chpok();
        }
    }
    public static class Extensions
    {
        public static IEnumerable<T> Chpok<T>(this IEnumerable<T> a) where T: struct
        {
            return a;
        }
    }
}