Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
You can send 1 Effect Monster from your hand to the GY; Special Summon 1 Level 4 or lower Dragon Normal Monster from your hand, Deck, or GY, in Defense Position. You can only use this effect of "Guardragon Corewakening" once per turn.
--守護竜の核醒
--Guardragon Corewakening
--Scripted by Eerie Code
local s,id=GetID()
function s.initial_effect(c)
	--activate
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	c:RegisterEffect(e1)
	--spsummon
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,0))
	e2:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e2:SetType(EFFECT_TYPE_QUICK_O)
	e2:SetRange(LOCATION_SZONE)
	e2:SetCode(EVENT_FREE_CHAIN)
	e2:SetHintTiming(0,TIMING_END_PHASE)
	e2:SetCountLimit(1,id)
	e2:SetCost(s.spcost)
	e2:SetTarget(s.sptg)
	e2:SetOperation(s.spop)
	c:RegisterEffect(e2)
end
function s.spcfilter(c)
	return c:IsType(TYPE_EFFECT) and c:IsAbleToGraveAsCost()
end
function s.spcost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.spcfilter,tp,LOCATION_HAND,0,1,nil) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_TOGRAVE)
	local g=Duel.SelectMatchingCard(tp,s.spcfilter,tp,LOCATION_HAND,0,1,1,nil)
	Duel.SendtoGrave(g,REASON_COST)
end
function s.spfilter(c,e,tp)
	return c:IsLevelBelow(4) and c:IsType(TYPE_NORMAL) and c:IsRace(RACE_DRAGON) and c:IsCanBeSpecialSummoned(e,0,tp,false,false,POS_FACEUP_DEFENSE)
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.GetLocationCount(tp,LOCATION_MZONE)>0
		and Duel.IsExistingMatchingCard(s.spfilter,tp,LOCATION_HAND|LOCATION_DECK|LOCATION_GRAVE,0,1,nil,e,tp) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,nil,1,tp,LOCATION_HAND|LOCATION_DECK|LOCATION_GRAVE)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	if Duel.GetLocationCount(tp,LOCATION_MZONE)<0 or not e:GetHandler():IsRelateToEffect(e) then return end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g=Duel.SelectMatchingCard(tp,aux.NecroValleyFilter(s.spfilter),tp,LOCATION_HAND|LOCATION_DECK|LOCATION_GRAVE,0,1,1,nil,e,tp)
	if #g>0 then
		Duel.SpecialSummon(g,0,tp,tp,false,false,POS_FACEUP_DEFENSE)
	end
end