code: func (u *UserV2) Check() error {
  	if u.Kind == "" {
  		return trace.BadParameter("user kind is not set")
  	}
  	if u.Version == "" {
  		return trace.BadParameter("user version is not set")
  	}
  	if u.Metadata.Name == "" {
  		return trace.BadParameter("user name cannot be empty")
  	}
  	for _, id := range u.Spec.OIDCIdentities {
  		if err := id.Check(); err != nil {
  			return trace.Wrap(err)
  		}
  	}
  	return nil
  }
docs: // Check checks validity of all parameters