pass flake8 on examples

define flake8 builtins for config files (c, get_config)

examples/cull-idle/jupyterhub_config.py

@@ -1,4 +1,7 @@
+import sys
+
 # run cull-idle as a service
+
 c.JupyterHub.services = [
     {
         'name': 'cull-idle',

examples/service-announcement/announcement.py

@@ -21,6 +21,7 @@ class AnnouncementRequestHandler(HubAuthenticated, web.RequestHandler):
     @web.authenticated
     def post(self):
         """Update announcement"""
+        user = self.current_user
         doc = escape.json_decode(self.request.body)
         self.storage["announcement"] = doc["announcement"]
         self.storage["timestamp"] = datetime.datetime.now().isoformat()

examples/service-announcement/jupyterhub_config.py

@@ -1,3 +1,4 @@
+import sys
 
 # To run the announcement service managed by the hub, add this.