Get a Metric for each registered view.

        Convert each registered view's associated `ViewData` into a `Metric` to
        be exported.

        :type timestamp: :class: `datetime.datetime`
        :param timestamp: The timestamp to use for metric conversions, usually
        the current time.

        :rtype: Iterator[:class: `opencensus.metrics.export.metric.Metric`]

def get_metrics(self, timestamp):
        """Get a Metric for each registered view.

        Convert each registered view's associated `ViewData` into a `Metric` to
        be exported.

        :type timestamp: :class: `datetime.datetime`
        :param timestamp: The timestamp to use for metric conversions, usually
        the current time.

        :rtype: Iterator[:class: `opencensus.metrics.export.metric.Metric`]
        """
        for vdl in self._measure_to_view_data_list_map.values():
            for vd in vdl:
                metric = metric_utils.view_data_to_metric(vd, timestamp)
                if metric is not None:
                    yield metric