/// <summary>
        /// Loads the data file in the format (worker id, task id, worker label, ?gold label).
        /// </summary>
        /// <param name="filename">The data file.</param>
        /// <returns>The list of parsed data.</returns>
        public static IList<Datum> LoadData(string filename)
        {
            var result = new List<Datum>();
            using (var reader = new StreamReader(filename))
            {
                string line;
                while ((line = reader.ReadLine()) != null)
                {
                    var strarr = line.Split(',');
                    int length = strarr.Length;

                    int workerLabel = int.Parse(strarr[2]);

                    var datum = new Datum()
                    {
                        WorkerId = strarr[0],
                        TaskId = strarr[1],
                        WorkerLabel = workerLabel,
                    };

                    if (length >= 4 && !strarr[3].Equals("NaN"))
                        datum.GoldLabel = int.Parse(strarr[3]);
                    else
                        datum.GoldLabel = null;

                    if (length == 5)
                        datum.TimeSpent = double.Parse(strarr[4]);
                    else
                        datum.TimeSpent = null;


                    result.Add(datum);
                }
            }

            return result;
        }
        private List<Datum> BuildDataFromAssignedLabels(Dictionary<string, int?> AssignedLabels, IList<Datum> OriginalData)
        {
            List<Datum> data = new List<Datum>();
            string firstWorkerId =WorkerIndexToId[0];
            foreach (var entry in AssignedLabels)
            {
               var datum = new Datum();
               datum.TaskId = entry.Key;
               datum.GoldLabel = entry.Value;
               datum.WorkerLabel = (int) entry.Value;
               datum.WorkerId = firstWorkerId;
               datum.BodyText = OriginalData.Where(d => d.TaskId == entry.Key).First().BodyText;
                
               data.Add(datum);
            }

            if (data.Count == 0)
                Console.WriteLine("*** Warning: There are no gold labels in the dataset ***");

            return data;
        }