code: func FromSubject(subject pkix.Name) (*Identity, error) {
  	i := &Identity{
  		Username:         subject.CommonName,
  		Groups:           subject.Organization,
  		Usage:            subject.OrganizationalUnit,
  		Principals:       subject.Locality,
  		KubernetesGroups: subject.Province,
  	}
  	if err := i.CheckAndSetDefaults(); err != nil {
  		return nil, trace.Wrap(err)
  	}
  	return i, nil
  }
docs: // FromSubject returns identity from subject name