using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public record Package (int Id, string Code);

    public static void Main()

    {

        var packages = new List<Package>();

        packages.Add(new Package(1, "0001"));

        packages.Add(new Package(2, "0002"));       

        packages.Add(new Package(1, "0001"));

        var dic = packages.ToDictionary(p => p.Id);

    }

}