def retry_task(self):
    """Ask taskqueue to retry this task.

    Even though raising an exception can cause a task retry, it
    will flood logs with highly visible ERROR logs. Handlers should uses
    this method to perform controlled task retries. Only raise exceptions
    for those deserve ERROR log entries.
    """
    self.response.set_status(httplib.SERVICE_UNAVAILABLE, "Retry task")
    self.response.clear()
Ask taskqueue to retry this task.

    Even though raising an exception can cause a task retry, it
    will flood logs with highly visible ERROR logs. Handlers should uses
    this method to perform controlled task retries. Only raise exceptions
    for those deserve ERROR log entries.