diff --git a/neo/client/mq.py b/neo/client/mq.py
index 6fbe96da7283ec887218c84ff6fb3c1227b21ed4..f8525f105022a313f82b0eb0fd3811eb3ef95ade 100644
--- a/neo/client/mq.py
+++ b/neo/client/mq.py
@@ -72,7 +72,7 @@ class FIFO(object):
     def shift(self):
         element = self._head
         if element is None:
-          return None
+            return None
         del self[element]
         del element.next
         del element.prev