diff --git a/neuralmonkey/runners/tensor_runner.py b/neuralmonkey/runners/tensor_runner.py
index 7ef7ec2ce..d4424598b 100644
--- a/neuralmonkey/runners/tensor_runner.py
+++ b/neuralmonkey/runners/tensor_runner.py
@@ -137,7 +137,8 @@ def __init__(self,
 
         total_tensors = len(tensors_by_name) + len(tensors_by_ref)
         if single_tensor and total_tensors > 1:
-            raise ValueError("single_tensor is True, but {} tensors were given".format(total_tensors))
+            raise ValueError("single_tensor is True, but {} tensors were given"
+                             .format(total_tensors))
 
         self._names = tensors_by_name
         self._tensors = tensors_by_ref