/// <param name="optional">Optional paramaters.</param>        /// <returns>ChannelListResponseResponse</returns>
        public static ChannelListResponse List(YouTubeService service, string part, ChannelsListOptionalParms optional = null)
        {
            try
            {
                // Initial validation.
                if (service == null)
                    throw new ArgumentNullException("service");
                if (part == null)
                    throw new ArgumentNullException(part);

                // Building the initial request.
                var request = service.Channels.List(part);

                // Applying optional parameters to the request.                
                request = (ChannelsResource.ListRequest)SampleHelpers.ApplyOptionalParms(request, optional);

                // Requesting data.
                return request.Execute();
            }
            catch (Exception ex)
            {
                throw new Exception("Request Channels.List failed.", ex);
            }
        }