/// <summary>
        ///
        /// </summary>
        static private void CheckIsValidClassification(
            Microsoft.UpdateServices.Administration.IUpdateServer server,
            Classification classification,
            System.String runSetName,
            System.String groupId
            )
        {
            //make sure the guid exists
            try
            {
                server.GetUpdateClassification(classification.Guid);
            }
            catch (System.Exception)
            {
                throw new System.ArgumentException(
                          "The Classification Guid \"" + classification.Guid + "\" could not be found on the WSUS server. Run Set: " + runSetName
                          );
            }

            //check for a product category collection
            ProductCollection products = classification.Products;

            if (products.ElementInformation.IsPresent)
            {
                //we have a collection
                CheckAreValidProducts(server, products, runSetName, groupId, classification.Guid.ToString());
            }
        }