Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If this card battles a Level 4 or lower monster, after damage calculation: You can return that monster to the hand.
--極星獣ガルム
--Garmr of the Nordic Beasts
local s,id=GetID()
function s.initial_effect(c)
	--destroy
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_TOHAND)
	e1:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_O)
	e1:SetCode(EVENT_BATTLED)
	e1:SetCondition(s.retcon)
	e1:SetTarget(s.rettg)
	e1:SetOperation(s.retop)
	c:RegisterEffect(e1)
end
function s.retcon(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetAttacker()
	if tc==e:GetHandler() then tc=Duel.GetAttackTarget() end
	if not tc then return false end
	e:SetLabelObject(tc)
	local lv=tc:GetLevel()
	return lv>0 and lv<=4 and not tc:IsStatus(STATUS_BATTLE_DESTROYED)
end
function s.rettg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk ==0 then	return e:GetLabelObject():IsAbleToHand() end
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,e:GetLabelObject(),0,0,0)
end
function s.retop(e,tp,eg,ep,ev,re,r,rp)
	if e:GetLabelObject():IsRelateToBattle() then
		Duel.SendtoHand(e:GetLabelObject(),nil,REASON_EFFECT)
	end
end