title: Google App Engine Python 2.7 Launcher - Localhost shows a blank page
body: <p>I was trying to complete an online tutorial and got stuck on this part. The app is running and the port is entered correctly. Instead of the form, the browser displays a blank page. </p>
  
  <pre><code>import webapp2
  
  form="""
  &lt;form method="post"&gt;
  What is your birthday?
  &lt;br&gt;
  &lt;br&gt;
  
  &lt;label&gt; Month
      &lt;input type="text" name="month"&gt;
  &lt;/label&gt;
  
  &lt;label&gt; Day
      &lt;input type="text" name="day"&gt;
  &lt;/label&gt;
  
  &lt;label&gt; Year
      &lt;input type="text" name="year"&gt;
  &lt;/label&gt;
  
  &lt;br&gt;
  &lt;br&gt;
  
  &lt;input type="submit"&gt;
  &lt;/form&gt;
  """
  
  class MainPage(webapp2.RequestHandler):
      def get(self):
          self.response.write(form)
  
      def post(self):
          user_month = valid_month(self.request.get('month'))
          user_day = valid_day(self.request.get('day'))
          user_year = valid_year(self.request.get('year'))
  
      if not (user_month and user_day and user_year):
          self.response.out.write(form)
      else:
          self.response.out.write("Thanks! That's a totally valid day!")
  
  app = webapp2.WSGIApplication([
      ('/', MainPage)
  ], debug=True)
  </code></pre>