code: func (s *Stage) Normalize() error {
  	switch st := s.GetStageType().(type) {
  	case *Stage_Failure:
  		return st.Failure.Normalize()
  	case *Stage_Stall:
  		return st.Stall.Normalize()
  	case *Stage_Deps:
  		return st.Deps.Normalize()
  	}
  	return fmt.Errorf("empty stage")
  }
docs: // Normalize checks Stage for errors and converts it to its normalized form.