code: func ToGroupMode(fluxMode functions.GroupMode) GroupMode {
  	switch fluxMode {
  	case functions.GroupModeNone:
  		return GroupModeDefault
  	case functions.GroupModeBy:
  		return GroupModeBy
  	case functions.GroupModeExcept:
  		return GroupModeExcept
  	default:
  		panic(fmt.Sprint("unknown group mode: ", fluxMode))
  	}
  }
docs: // ToGroupMode accepts the group mode from Flux and produces the appropriate storage group mode.