code: func NewUserNotAllowedError(image string, onbuild bool) error {
  	var msg string
  	if onbuild {
  		msg = fmt.Sprintf("image %q includes at least one ONBUILD instruction that sets the user to a user that is not allowed", image)
  	} else {
  		msg = fmt.Sprintf("image %q must specify a user that is numeric and within the range of allowed users", image)
  	}
  	return Error{
  		Message:    msg,
  		ErrorCode:  UserNotAllowedError,
  		Suggestion: fmt.Sprintf("modify image %q to use a numeric user within the allowed range, or build without the allowed UIDs paremeter set", image),
  	}
  }
docs: // NewUserNotAllowedError returns a new error that indicates that the build
  // could not run because the image uses a user outside of the range of allowed users