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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 get_metric(self, timestamp):
 """Get a metric including all current time series. Get a :class:`opencensus.metrics.export.metric.Metric` with one :class:`opencensus.metrics.export.time_series.TimeSeries` for each set of label values with a recorded measurement. Each `TimeSeries` has a single point that represents the last recorded value. :type timestamp: :class:`datetime.datetime` :param timestamp: Recording time to report, usually the current time. :rtype: :class:`opencensus.metrics.export.metric.Metric` or None :return: A converted metric for all current measurements. """

        if not self.points:
            return None

        with self._points_lock:
            ts_list = get_timeseries_list(self.points, timestamp)
        return metric.Metric(self.descriptor, ts_list)