Geocoding with named task queue parameters on App Engine

queue.yaml

queue:
- name: geocoding
  rate: 1/m
  retry_parameters:
    task_retry_limit: 60
    task_age_limit:   3d
    min_backoff_seconds: 120

routers.py

def new_user_from_form(form):
    user = models.User())
    update_user_from_form(user, form)
    deferred.defer(models.User.calculate_timezone_for_user, user.get_id(), _queue="geocoding")
    return user

user.py

class User(db.Model):
   # stuff

   @classmethod
   def calculate_timezone_for_user(cls, user_or_id):
        user = convert_to_user(user_or_id)
        user.calculate_timezone() 

   def calculate_timezone(self):
        import geocoder

        try:
            geocoder_client = geocoder.Geocoder()
            geocoder_result = geocoder_client.geocode(self.location.encode('utf-8'))
            self.latlng  = db.GeoPt(*geocoder_result.coordinates)
        except geocoder.GeocoderError, err:
            if err.status == geocoder.GeocoderError.G_GEO_OVER_QUERY_LIMIT:
                logging.info('Went over geocoding query limit.')
                raise
            else:
                logging.error('Error geocoding location for user %s: %s' % (self.get_id(), err))