Fix flake8 in heka_alarming.py
diff --git a/_modules/heka_alarming.py b/_modules/heka_alarming.py
index 147335b..8f86efd 100644
--- a/_modules/heka_alarming.py
+++ b/_modules/heka_alarming.py
@@ -27,7 +27,8 @@
 
 
 def alarm_activate_alerting(alerting):
-    return 'true' if alerting in ['enabled', 'enabled_with_notification'] else 'false'
+    return ('true' if alerting in ['enabled', 'enabled_with_notification']
+            else 'false')
 
 
 def alarm_enable_notification(alerting):