code: public void registerAny(Metric2Set metrics) {
  		for (Map.Entry<MetricName, Metric> entry : metrics.getMetrics().entrySet()) {
  			registerNewMetrics(entry.getKey(), entry.getValue());
  		}
  	}
docs: Given a metric set, registers the ones not already registered.
  This method prevents IllegalArgumentException
  @param metrics a set of metrics