Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Target 2 monsters you control of the same Type with 1000 or less ATK; both monsters' Levels become the combined Levels of those 2 monsters.
--タンホイザーゲート
--Tannhauser Gate
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
end
function s.filter1(c,tp)
	return c:IsLevelAbove(1) and c:IsAttackBelow(1000)
		and Duel.IsExistingTarget(s.filter2,tp,LOCATION_MZONE,0,1,c,c:GetRace())
end
function s.filter2(c,rac)
	return c:IsLevelAbove(1) and c:IsAttackBelow(1000) and c:IsRace(rac)
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsLocation(LOCATION_MZONE) and chkc:IsFaceup() end
	if chk==0 then return Duel.IsExistingTarget(s.filter1,tp,LOCATION_MZONE,0,1,nil,tp) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_FACEUP)
	local g1=Duel.SelectTarget(tp,s.filter1,tp,LOCATION_MZONE,0,1,1,nil,tp)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_FACEUP)
	Duel.SelectTarget(tp,s.filter2,tp,LOCATION_MZONE,0,1,1,g1:GetFirst(),g1:GetFirst():GetRace())
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	local g=Duel.GetChainInfo(0,CHAININFO_TARGET_CARDS)
	local tc1=g:GetFirst()
	local tc2=g:GetNext()
	if tc1:IsRelateToEffect(e) and tc1:IsFaceup() and tc2:IsRelateToEffect(e) and tc2:IsFaceup() then
		local lv=tc1:GetLevel()+tc2:GetLevel()
		local e1=Effect.CreateEffect(e:GetHandler())
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_CHANGE_LEVEL_FINAL)
		e1:SetValue(lv)
		e1:SetReset(RESET_EVENT|RESETS_STANDARD)
		tc1:RegisterEffect(e1)
		local e2=e1:Clone()
		tc2:RegisterEffect(e2)
	end
end