From c80c19be0d15c81dfe39cddfdb744383ed1d839c Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Wed, 3 Aug 2016 12:12:11 +0100
Subject: [PATCH] Fix missed in traitlets API overhaul

Closes gh-1649
---
 notebook/notebookapp.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/notebook/notebookapp.py b/notebook/notebookapp.py
index a0972475c..9a5f3d122 100644
--- a/notebook/notebookapp.py
+++ b/notebook/notebookapp.py
@@ -844,7 +844,7 @@ class NotebookApp(JupyterApp):
     @observe('pylab')
     def _update_pylab(self, change):
         """when --pylab is specified, display a warning and exit"""
-        if new != 'warn':
+        if change['new'] != 'warn':
             backend = ' %s' % change['new']
         else:
             backend = ''