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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def publish_time(self):
 """Return the time that the message was originally published. Returns: datetime: The date and time that the message was published. """

        timestamp = self._message.publish_time
        delta = datetime.timedelta(
            seconds=timestamp.seconds, microseconds=timestamp.nanos // 1000
        )
        return datetime_helpers._UTC_EPOCH + delta