diff --git a/pytorch_lightning/models/trainer.py b/pytorch_lightning/models/trainer.py
index ae7f139201..a485682c1f 100644
--- a/pytorch_lightning/models/trainer.py
+++ b/pytorch_lightning/models/trainer.py
@@ -395,6 +395,7 @@ class Trainer(TrainerIO):
 
         # forward pass
         # return a scalar value and a dic with tqdm metrics
+        # TODO: fix training part...
         loss, model_specific_tqdm_metrics_dic = self.model.training_step(data_batch, batch_nb)
         self.__add_tqdm_metrics(model_specific_tqdm_metrics_dic)