allow_none=False by default for Type and Instance

SylvainCorlay · SylvainCorlay · commit 9d1c6996e983 · 2015-03-27T19:34:59.000-04:00
diff --git a/config.py b/config.py
@@ -114,6 +114,7 @@ def _figure_format_changed(self, name, old, new):
         be explicit.
         """)
     
-    shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
+    shell = Instance('IPython.core.interactiveshell.InteractiveShellABC',
+                     allow_none=True)
 
 
