def _timestamp_message(self, attrs):
        if self.timestamp_messages and 'timestamp' not in attrs:
            attrs['timestamp'] = _datetime_to_rfc3339(_NOW())
Add a timestamp to ``attrs``, if the topic is so configured.
dataset/ETHPy150Open GoogleCloudPlatform/gcloud-python/gcloud/pubsub/topic.py/Topic._timestamp_message