using System;

using System.Collections.Generic;           

​

public class Program

{

    public static void Main()

    {

        List<InstancePackage> list = new List<InstancePackage>();

        var installedPackage = list.GetInstalledPackage();

        var installingPackage = list.GetInstallingPackage();

        Console.WriteLine("Done");

        Console.ReadLine();

    }

}

​

public static class InstancePackageFilteringExtensions

{

    public static InstancePackage GetInstalledPackage(this List<InstancePackage> obj)

    {

        // Filtering logic here

        return new InstancePackage();

    }

​

    public static InstancePackage GetInstallingPackage(this List<InstancePackage> obj)

    {

        // Filtering logic here

        return new InstancePackage();

    }

}

​

public class InstancePackage

{

}