private void SaveExcludedTrainingIDInfo() throws Exception {
   ArrayList<String> excludedTrainingIDs =
       Singletons.InstanceVault.GetCrossValidationAssignments().GetAllExcludedTrainIDs();
   if (excludedTrainingIDs.size() > 0) {
     String filePath = Settings.GetOutputSettingsDir(true) + "Excluded_Training_IDs.txt";
     String output = ListUtilities.Join(excludedTrainingIDs, "\n");
     FileUtilities.WriteLineToFile(
         filePath,
         "# IDs of data instances that were excluded randomly from training sets, according to the specified experiment settings. If this is a cross-validation experiment, the instances were removed from different folds.");
     FileUtilities.AppendLineToFile(filePath, output);
   }
 }