diff --git a/docs/LightningModule/RequiredTrainerInterface.md b/docs/LightningModule/RequiredTrainerInterface.md
index d8ccae94f3..6308d5696c 100644
--- a/docs/LightningModule/RequiredTrainerInterface.md
+++ b/docs/LightningModule/RequiredTrainerInterface.md
@@ -145,7 +145,7 @@ def training_step(self, batch, batch_nb):
     
     output = {
         'loss': loss, # required
-        'progress': {'training_loss': loss, 'batch_nb': batch_nb} # optional
+        'progress': {'training_loss': loss} # optional (MUST ALL BE TENSORS)
     }
     
     # return a dict