using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

}

​

public class Metal{}

public class Steel:Metal{}

​

public class MetalPickerContext

{

    public int Condition1{ get;set;}

}

​

public class MetalPicker<TMetal, TContext> 

    where TMetal: Metal

    where TContext: MetalPickerContext

{

    public virtual IEnumerable<TMetal> GetBest(IEnumerable<TMetal> list, TContext context)

    {

        var result = new List<TMetal>();

        return result;

    }

}

​

public class SteelPickerContext: MetalPickerContext

{

    public int Condition2{get;set;}

}

​

public class SteelPicker : MetalPicker<Steel,SteelPickerContext>

{

    public override IEnumerable<Steel> GetBest(IEnumerable<Steel> list, SteelPickerContext context)

    {

        var initialResult = base.GetBest(list,context);

        return initialResult;

    }

}