missing allow_none=True

SylvainCorlay · SylvainCorlay · commit 6cd8d5cfe9d5 · 2015-03-27T20:03:46.000-04:00
diff --git a/IPython/kernel/zmq/session.py b/IPython/kernel/zmq/session.py
@@ -341,7 +341,7 @@ def _signature_scheme_changed(self, name, old, new):
     def _digest_mod_default(self):
         return hashlib.sha256
     
-    auth = Instance(hmac.HMAC)
+    auth = Instance(hmac.HMAC, allow_none=True)
     
     def _new_auth(self):
         if self.key:
