internal static void Remove(this X509ExtensionCollection exts, String oid)
 {
     if (exts == null)
     {
         return;
     }
     for (Int32 i = 0; i < exts.Count; i++)
     {
         if (exts[i].Oid.Value == oid)
         {
             exts.RemoveAt(i);
             return;
         }
     }
 }