code: def get_metrics(self, timestamp):
          
          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
docs: 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`]