diff --git a/src/mednet/data/datamodule.py b/src/mednet/data/datamodule.py
index 9dd094a27a38f0e547d5a2e66e5a177514903c06..4f79857b88eeb7a7fada2bf40f29ebb9dcfe7209 100644
--- a/src/mednet/data/datamodule.py
+++ b/src/mednet/data/datamodule.py
@@ -625,6 +625,7 @@ class ConcatDataModule(lightning.LightningDataModule):
 
         Returns
         -------
+        list
             A list containing the model tansforms.
         """
         return self._model_transforms