code: def get_metrics(self):
          
          now = datetime.utcnow()
          metrics = set()
          for gauge in self.gauges.values():
              metrics.add(gauge.get_metric(now))
          return metrics
docs: Get a metric for each gauge in the registry at the current time.
  
          :rtype: set(:class:`opencensus.metrics.export.metric.Metric`)
          :return: A set of `Metric`s, one for each registered gauge.