Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Fusion Summon 1 "Cubic" Fusion Monster from your Extra Deck, using monsters from your hand or field as Fusion Materials. If a face-up "Cubic" monster is destroyed by battle or leaves the field: You can banish this card from your Graveyard; Special Summon 1 Level 4 or lower "Cubic" monster from your hand or Deck, ignoring its Summoning conditions, and if you do, it cannot be destroyed by battle or card effects this turn.
--方界合神
--Unification of the Cubic Lords
local s,id=GetID()
function s.initial_effect(c)
	--Fusion 1 "Cubic" fusion monster
	--Use monsters from hand or field as fusion materials
	c:RegisterEffect(Fusion.CreateSummonEff(c,aux.FilterBoolFunction(Card.IsSetCard,SET_CUBIC)))
	--Special summon 1 level 4 or lower "Cubic" monster from hand or deck
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,1))
	e2:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e2:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_TRIGGER_O)
	e2:SetCode(EVENT_LEAVE_FIELD)
	e2:SetRange(LOCATION_GRAVE)
	e2:SetProperty(EFFECT_FLAG_DELAY+EFFECT_FLAG_DAMAGE_STEP)
	e2:SetCondition(s.spcon)
	e2:SetCost(Cost.SelfBanish)
	e2:SetTarget(s.sptg)
	e2:SetOperation(s.spop)
	c:RegisterEffect(e2)
end
s.listed_series={SET_CUBIC}
function s.cfilter(c)
	return c:IsPreviousSetCard(SET_CUBIC) and c:IsPreviousLocation(LOCATION_MZONE)
		and c:IsPreviousPosition(POS_FACEUP)
end
function s.spcon(e,tp,eg,ep,ev,re,r,rp)
	return eg:IsExists(s.cfilter,1,nil)
end
function s.spfilter(c,e,tp)
	return c:IsSetCard(SET_CUBIC) and c:IsLevelBelow(4) and c:IsCanBeSpecialSummoned(e,0,tp,true,false)
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,0,1,nil,e,tp) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,nil,1,tp,LOCATION_HAND|LOCATION_DECK)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	if Duel.GetLocationCount(tp,LOCATION_MZONE)<=0 then return end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g=Duel.SelectMatchingCard(tp,s.spfilter,tp,LOCATION_HAND|LOCATION_DECK,0,1,1,nil,e,tp)
	if #g>0 and Duel.SpecialSummon(g,0,tp,tp,true,false,POS_FACEUP)~=0 then
		--Cannot be destroyed by battle or card effect
		local e1=Effect.CreateEffect(e:GetHandler())
		e1:SetDescription(3008)
		e1:SetProperty(EFFECT_FLAG_CLIENT_HINT)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_INDESTRUCTABLE_BATTLE)
		e1:SetValue(1)
		e1:SetReset(RESETS_STANDARD_PHASE_END)
		g:GetFirst():RegisterEffect(e1)
		local e2=e1:Clone()
		e2:SetCode(EFFECT_INDESTRUCTABLE_EFFECT)
		g:GetFirst():RegisterEffect(e2)
	end
end