Implement interface

Hi

I Am Create Class Library And Create New Class With Implements Of Interface But By Error

IStringToken Is Interface

Demo is New Class

namespace ClassLibrary2
{
    public class Demo: ZLDNN.Modules.DNNArticle.IStringToken
    {

    }
}

Error:

Error    5    'ClassLibrary2.Demo' does not implement interface member 'ZLDNN.Modules.DNNArticle.IStringToken.ProcessTokenShamsiIcon(ZLDNN.Modules.DNNArticle.DNNArticleInfo, string, string)'    c:\users\moayery\documents\visual studio 2012\Projects\ClassLibrary2\Demo.cs   9    18    ClassLibrary2

I Thank For HelpMe