code: func NewACIdentifier(s string) (*ACIdentifier, error) {
  	n := ACIdentifier(s)
  	if err := n.assertValid(); err != nil {
  		return nil, err
  	}
  	return &n, nil
  }
docs: // NewACIdentifier generates a new ACIdentifier from a string. If the given string is
  // not a valid ACIdentifier, nil and an error are returned.