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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 _maybe_set_message_age(self):
 """If timestamp is set and the relative age is > 0, record age of the message coming in """

        if self._message.properties.timestamp:
            message_age = float(
                max(self._message.properties.timestamp, time.time()) -
                self._message.properties.timestamp)
            if message_age > 0:
                self.measurement.add_duration(
                    self.message_age_key(), message_age)