Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
This card can be treated as 2 Tributes for the Tribute Summon of a Dragon monster. While this card is in your hand or GY, if a face-up Dragon monster on the field, except "Keeper of the Shrine", is sent to the GY by a card effect or because it was destroyed by battle: You can Special Summon this card, then, if that monster sent to the GY is a Normal Monster, you can add 1 Dragon Normal Monster from your GY to your hand. You can only use this effect of "Keeper of the Shrine" once per turn.
--霊廟の守護者
--Keeper of the Shrine
local s,id=GetID()
function s.initial_effect(c)
	--Double tribute for the Tribute Summon of Dragon monsters
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetCode(EFFECT_DOUBLE_TRIBUTE)
	e1:SetValue(function (e,c) return c:IsRace(RACE_DRAGON) end)
	c:RegisterEffect(e1)
	--Special Summon itself from the GY and add 1 Dragon monster from the GY to the hand
	local e2=Effect.CreateEffect(c)
	e2:SetCategory(CATEGORY_SPECIAL_SUMMON+CATEGORY_TOHAND)
	e2:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_TRIGGER_O)
	e2:SetCode(EVENT_TO_GRAVE)
	e2:SetRange(LOCATION_HAND|LOCATION_GRAVE)
	e2:SetProperty(EFFECT_FLAG_DAMAGE_STEP+EFFECT_FLAG_DELAY)
	e2:SetCountLimit(1,id)
	e2:SetCondition(s.spcon)
	e2:SetTarget(s.sptg)
	e2:SetOperation(s.spop)
	c:RegisterEffect(e2)
end
s.listed_names={id}
function s.cfilter(c)
	return c:IsRace(RACE_DRAGON) and c:GetPreviousRaceOnField()==RACE_DRAGON
		and c:IsPreviousPosition(POS_FACEUP) and c:IsPreviousLocation(LOCATION_MZONE)
		and c:IsReason(REASON_EFFECT|REASON_BATTLE) and not c:IsCode(id)
end
function s.spcon(e,tp,eg,ep,ev,re,r,rp)
	if eg:IsContains(e:GetHandler()) then return false end
	local g=eg:Filter(s.cfilter,nil)
	if #g==0 then return false end
	e:SetLabel(0)
	if g:IsExists(Card.IsType,1,nil,TYPE_NORMAL) then
		e:SetLabel(1)
	end
	return true
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 e:GetHandler():IsCanBeSpecialSummoned(e,0,tp,false,false) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,e:GetHandler(),1,0,0)
	Duel.SetPossibleOperationInfo(0,CATEGORY_TOHAND,nil,1,tp,LOCATION_GRAVE)
end
function s.thfilter(c)
	return c:IsRace(RACE_DRAGON) and c:IsType(TYPE_NORMAL) and c:IsAbleToHand()
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	if Duel.GetLocationCount(tp,LOCATION_MZONE)<=0 then return end
	local c=e:GetHandler()
	local g=Duel.GetMatchingGroup(aux.NecroValleyFilter(s.thfilter),tp,LOCATION_GRAVE,0,nil)
	if not c:IsRelateToEffect(e) then return end
	if Duel.SpecialSummon(c,0,tp,tp,false,false,POS_FACEUP)~=0 and e:GetLabel()==1
		and #g>0 and Duel.SelectYesNo(tp,aux.Stringid(id,0)) then
		Duel.BreakEffect()
		Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_ATOHAND)
		local sg=g:Select(tp,1,1,nil)
		Duel.SendtoHand(sg,nil,REASON_EFFECT)
		Duel.ConfirmCards(1-tp,sg)
	end
end