code: def handle_exception_404(self, e):
          
          logger.debug("A 404 Not Found exception occurred while handling "
                       "the request.")
          self.response.body_raw = {'error': 'Not Found'}
          self.response.status = 404
docs: Handle the given exception. Log, sets the response code to 404 and
          output the exception message as an error message.
  
          :param e: Exception which is being handled.
          :type e: :class:`Exception`