diff --git a/pytorch_lightning/trainer/trainer_io.py b/pytorch_lightning/trainer/trainer_io.py
index 98bf58a9..aa40e21d 100644
--- a/pytorch_lightning/trainer/trainer_io.py
+++ b/pytorch_lightning/trainer/trainer_io.py
@@ -1,6 +1,7 @@
 import os
 import re
 import signal
+import warnings
 from subprocess import call
 
 import torch