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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 _convert_series(self, metric, ts):
 """Convert an OC timeseries to a SD series."""

        series = monitoring_v3.types.TimeSeries()
        series.metric.type = self.get_metric_type(metric.descriptor)

        for lk, lv in self.options.default_monitoring_labels.items():
            series.metric.labels[lk.key] = lv.value

        for key, val in zip(metric.descriptor.label_keys, ts.label_values):
            if val.value is not None:
                safe_key = sanitize_label(key.key)
                series.metric.labels[safe_key] = val.value

        set_monitored_resource(series, self.options.resource)

        for point in ts.points:
            sd_point = series.points.add()
            # this just modifies points, no return
            self._convert_point(metric, ts, point, sd_point)
        return series