diff --git a/src/main/java/be/cylab/java/wowa/training/Trainer.java b/src/main/java/be/cylab/java/wowa/training/Trainer.java
index b1db1d919fe93fa482f1ff8787c25f6edb4d5223..f4d98e380aa2e7e9444deff652197f7a13f10acd 100644
--- a/src/main/java/be/cylab/java/wowa/training/Trainer.java
+++ b/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();