code: func validateLabelsAndMetricName(ls labels.Labels) error {
  	for _, l := range ls {
  		if l.Name == labels.MetricName && !model.IsValidMetricName(model.LabelValue(l.Value)) {
  			return errors.Errorf("invalid metric name: %v", l.Value)
  		}
  		if !model.LabelName(l.Name).IsValid() {
  			return errors.Errorf("invalid label name: %v", l.Name)
  		}
  		if !model.LabelValue(l.Value).IsValid() {
  			return errors.Errorf("invalid label value: %v", l.Value)
  		}
  	}
  	return nil
  }
docs: // validateLabelsAndMetricName validates the label names/values and metric names returned from remote read.