using System;
using System.Collections.Generic;
using System.Text;

namespace System.Runtime.CompilerServices
{
    [
        AttributeUsage ( AttributeTargets.Method | AttributeTargets.Class |
            AttributeTargets.Assembly )
    ]
    public sealed class ExtensionAttribute : Attribute
    {
    }
}

namespace ClassLibrary3
{
    public static class Ext
    {
        public static string DoStr ( this string sStr )
        {
            return ( sStr );
        }
    }
    
    public class Class1
    {
        private List<string> m_oStrings = new List<string> ();
        
        public void Something ( int nValue )
        {
            nValue = m_oStrings[m_oStrings.Count - 1].DoStr ().Length;
        }
    }
}