diff --git a/IPython/frontend/html/notebook/handlers.py b/IPython/frontend/html/notebook/handlers.py
index ed0fe6a..ba0bfd2 100644
--- a/IPython/frontend/html/notebook/handlers.py
+++ b/IPython/frontend/html/notebook/handlers.py
@@ -596,7 +596,7 @@ class NotebookRootHandler(AuthenticatedHandler):
             nid = f['notebook_id']
             kid = km.kernel_for_notebook(nid)
             if  kid is not None:
-                f['kernel_id']=kid
+                f['kernel_id'] = kid
         self.finish(jsonapi.dumps(files))
 
     @web.authenticated