making flake8 happy

ned2 · ned2 · commit 8a46164b0130 · 2018-01-06T01:41:34.000+11:00
diff --git a/dash/exceptions.py b/dash/exceptions.py
@@ -41,5 +41,6 @@ class IDsCantContainPeriods(CallbackException):
 class CantHaveMultipleOutputs(CallbackException):
     pass
 
+
 class PreventUpdate(CallbackException):
     pass
