old_contents: __version__ = "0.1.0"
  
  
  class HelloResource(object):
  
      def on_get(self, req, res):
          res.body = "Hello"
  
  
  hello_resource = HelloResource()
  
  
  def install_module(app):
      app.add_route('/example', hello_resource)
  
new_contents: __version__ = '0.1.0'
  
  
  class HelloResource(object):
  
      def on_get(self, req, res):
          res.body = 'Hello'
  
  
  hello_resource = HelloResource()
  
  
  def install_module(app):
      app.add_route('/example', hello_resource)
  
subject: Use single quotes.