Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Once per turn: You can target 1 Level 4 or lower "Scrap" monster in your GY; Special Summon that target to either player's field.
--スクラップ・ゴーレム
--Scrap Golem
local s,id=GetID()
function s.initial_effect(c)
	--Special Summon 1 Level 4 or lower "Scrap" monster
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_IGNITION)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetRange(LOCATION_MZONE)
	e1:SetCountLimit(1)
	e1:SetTarget(s.sptg)
	e1:SetOperation(s.spop)
	c:RegisterEffect(e1)
end
s.listed_series={SET_SCRAP}
function s.spfilter(c,e,tp)
	return c:IsLevelBelow(4) and c:IsSetCard(SET_SCRAP) and (c:IsCanBeSpecialSummoned(e,0,tp,false,false)
		or c:IsCanBeSpecialSummoned(e,0,tp,false,false,POS_FACEUP,1-tp))
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsLocation(LOCATION_GRAVE) and chkc:IsControler(tp) and s.filter(chkc,e,tp) end
	if chk==0 then return (Duel.GetLocationCount(tp,LOCATION_MZONE)>0 or Duel.GetLocationCount(1-tp,LOCATION_MZONE)>0)
		and Duel.IsExistingTarget(s.spfilter,tp,LOCATION_GRAVE,0,1,nil,e,tp) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g=Duel.SelectTarget(tp,s.spfilter,tp,LOCATION_GRAVE,0,1,1,nil,e,tp)
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,g,1,0,0)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if not tc:IsRelateToEffect(e) then return end
	local b1=Duel.GetLocationCount(tp,LOCATION_MZONE)>0 and tc:IsCanBeSpecialSummoned(e,0,tp,false,false)
	local b2=Duel.GetLocationCount(1-tp,LOCATION_MZONE)>0 and tc:IsCanBeSpecialSummoned(e,0,tp,false,false,POS_FACEUP,1-tp)
	local op=0
	Duel.Hint(HINT_SELECTMSG,tp,0)
	if b1 and b2 then
		op=Duel.SelectOption(tp,aux.Stringid(id,1),aux.Stringid(id,2))
	elseif b1 then
		op=Duel.SelectOption(tp,aux.Stringid(id,1))
	elseif b2 then
		op=Duel.SelectOption(tp,aux.Stringid(id,2))+1
	else return end
	if op==0 then
		Duel.SpecialSummon(tc,0,tp,tp,false,false,POS_FACEUP)
	else
		Duel.SpecialSummon(tc,0,tp,1-tp,false,false,POS_FACEUP)
	end
end