code: public Metric updateMetric(String metricName) {
      // [START updateMetric]
      MetricInfo metricInfo =
          MetricInfo.newBuilder(metricName, "severity>=ERROR")
              .setDescription("new description")
              .build();
      Metric metric = logging.update(metricInfo);
      // [END updateMetric]
      return metric;
    }
docs: [VARIABLE "my_metric_name"]