code: func GetLoginShell(username string) (string, error) {
  	var err error
  	var shellcmd string
  
  	shellcmd, err = getLoginShell(username)
  	if err != nil {
  		if !trace.IsNotFound(err) {
  			logrus.Warnf("No shell specified for %v, using default %v.", username, DefaultShell)
  			return DefaultShell, nil
  		}
  		return "", trace.Wrap(err)
  	}
  
  	return shellcmd, nil
  }
docs: // GetLoginShell determines the login shell for a given username.