Update guestbook.py
Update guestbook.py

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jerarl/gcp-appengine-python,ashwini0529/appengine-guestbook-python,GoogleCloudPlatform/appengine-guestbook-python,dmolson/appengine-guestbook-python,adjohnson916/appengine-guestbook-python,dmolson/appengine-guestbook-python,ashwini0529/appengine-guestbook-python,thejeshgn/appengine-guestbook-python,artificechicago/camp2016,adjohnson916/appengine-guestbook-python,danylo-bondarenko/PySanbox,iedexmain2/appengine-guestbook-python,niickattack/testinggitit,jerarl/gcp-appengine-python,bkeyvani/appengine-guestbook-python,bkeyvani/appengine-guestbook-python,niickattack/testinggitit,t9nf/appengine-guestbook-python,JackConnor/portfolio,JackConnor/portfolio,cbeloni/appengine-guestbook-python,psigen/ledgerlemur,jeffgodwyll/appengine-flask-guestbook,thejeshgn/appengine-guestbook-python,t9nf/appengine-guestbook-python,Romzz/appengine-guestbook-python,wcyuan/weather-mailer,JonGal/appengine-ml-demo,GoogleCloudPlatform/appengine-guestbook-python,Romzz/appengine-guestbook-python,wcyuan/weather-mailer,alkababa/default-code-appengine,artificechicago/camp2016,jeffgodwyll/appengine-flask-guestbook,JonGal/appengine-ml-demo,iedexmain2/appengine-guestbook-python