def populate_times(self):
        """
        Populates all different meta data times that comes with measurement if
        they are present.
        """
        stop_time = self.meta_data.get("stop_time")
        if stop_time:
            stop_naive = datetime.utcfromtimestamp(stop_time)
            self.stop_time = stop_naive.replace(tzinfo=tzutc())

        creation_time = self.meta_data.get("creation_time")
        if creation_time:
            creation_naive = datetime.utcfromtimestamp(creation_time)
            self.creation_time = creation_naive.replace(tzinfo=tzutc())

        start_time = self.meta_data.get("start_time")
        if start_time:
            start_naive = datetime.utcfromtimestamp(start_time)
            self.start_time = start_naive.replace(tzinfo=tzutc())
Populates all different meta data times that comes with measurement if
        they are present.