Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
When an opponent's monster declares an attack: Target 1 monster you control; return that target to the hand, then Special Summon 1 Level 4 monster from your hand.
--モンスターレリーフ
--Relieve Monster
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_TOHAND+CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetCode(EVENT_ATTACK_ANNOUNCE)
	e1:SetCondition(s.condition)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
end
function s.condition(e,tp,eg,ep,ev,re,r,rp)
	return Duel.IsTurnPlayer(1-tp)
end
function s.filter(c,ft)
	return c:IsAbleToHand() and (ft>0 or c:GetSequence()<5)
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	local ft=Duel.GetLocationCount(tp,LOCATION_MZONE)
	if chkc then return chkc:IsLocation(LOCATION_MZONE) and chkc:IsControler(tp) and s.filter(chkc,ft) end
	if chk==0 then return ft>-1 and Duel.IsExistingTarget(s.filter,tp,LOCATION_MZONE,0,1,nil,ft)
		and Duel.IsExistingMatchingCard(s.spfilter,tp,LOCATION_HAND,0,1,nil,e,tp) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_RTOHAND)
	local g=Duel.SelectTarget(tp,s.filter,tp,LOCATION_MZONE,0,1,1,nil,ft)
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,g,1,0,0)
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,nil,1,tp,LOCATION_HAND)
end
function s.spfilter(c,e,tp)
	return c:GetLevel()==4 and c:IsCanBeSpecialSummoned(e,0,tp,false,false)
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc and tc:IsRelateToEffect(e) and Duel.SendtoHand(tc,nil,REASON_EFFECT)>0
		and tc:IsLocation(LOCATION_HAND) and Duel.GetLocationCount(tp,LOCATION_MZONE)>0 then
		Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
		local g=Duel.SelectMatchingCard(tp,s.spfilter,tp,LOCATION_HAND,0,1,1,nil,e,tp)
		Duel.SpecialSummon(g,0,tp,tp,false,false,POS_FACEUP)
	end
end