code: func LabelsFromMap(labelsMap map[ACIdentifier]string) (Labels, error) {
  	labels := Labels{}
  	for n, v := range labelsMap {
  		labels = append(labels, Label{Name: n, Value: v})
  	}
  	if err := labels.assertValid(); err != nil {
  		return nil, err
  	}
  	sort.Sort(labelsSlice(labels))
  	return labels, nil
  }
docs: // LabelsFromMap creates Labels from a map[ACIdentifier]string