fixing app.py

voting-app/app.py

@@ -36,7 +36,6 @@ def hello():
         hostname=hostname,
         vote=vote,
     ))
-    resp.headers['Cache-Control'] = 'no-store, no-cache, must-revalidate, post-check=0, pre-check=0, max-age=0';
     resp.set_cookie('voter_id', voter_id)
     return resp