Correct checkstyle issues

src/main/java/be/cylab/java/wowa/training/Trainer.java

@@ -158,7 +158,7 @@ public class Trainer {
      * @param expected
      * @param increase_ratio
      */
-    TrainingDataset increaseTrueAlert(
+    final TrainingDataset increaseTrueAlert(
             final List<List<Double>> data,
             final List<Double> expected,
             final int increase_ratio) {
@@ -181,7 +181,7 @@ public class Trainer {
      * @param fold_number
      * @return
      */
-     List<TrainingDataset> prepareFolds(
+     final List<TrainingDataset> prepareFolds(
             final TrainingDataset dataset,
             final int fold_number) {
         //List<List<Double>> data = dataset.getData();