Merge pull request #11978 from Carreau/fix-mime-bokeh

Handle case where the shell does not have arbitrary mimerenderer handler

IPython/core/displaypub.py

@@ -105,7 +105,7 b' class DisplayPublisher(Configurable):'
 
         handlers = {}
         if self.shell is not None:
-            handlers = self.shell.mime_renderers
+            handlers = getattr(self.shell, 'mime_renderers', {})
 
         for mime, handler in handlers.items():
             if mime in data: