Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Activate this card by Tributing 1 "Ninja" monster; Special Summon any number of "Ninja" monsters from your Deck, in face-up Attack Position and/or face-down Defense Position, with combined Levels less than or equal to the Level of the Tributed monster. When this card leaves the field, destroy those monsters.
--忍法 分身の術
--Ninjitsu Art of Duplication
local s,id=GetID()
function s.initial_effect(c)
	--Tribute 1 "Ninja" and Special Summon "Ninja" monsters from the Deck
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetHintTiming(0,TIMINGS_CHECK_MONSTER_E)
	e1:SetTarget(s.target)
	e1:SetOperation(s.operation)
	c:RegisterEffect(e1)
	--Destroy the Special Summoned monster(s) when leaving the field
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_CONTINUOUS+EFFECT_TYPE_SINGLE)
	e2:SetCode(EVENT_LEAVE_FIELD)
	e2:SetOperation(s.desop)
	c:RegisterEffect(e2)
end
s.listed_series={SET_NINJA}
function s.cfilter(c,e,tp)
	local lv=c:GetLevel()
	return lv>0 and c:IsSetCard(SET_NINJA) and Duel.GetMZoneCount(tp,c)>0 and Duel.IsExistingMatchingCard(s.spfilter,tp,LOCATION_DECK,0,1,nil,e,tp,lv)
end
function s.spfilter(c,e,tp,lv)
	return c:IsLevelBelow(lv) and c:IsSetCard(SET_NINJA) and c:IsCanBeSpecialSummoned(e,0,tp,false,false,POS_FACEUP_ATTACK|POS_FACEDOWN_DEFENSE)
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.CheckReleaseGroupCost(tp,s.cfilter,1,false,nil,nil,e,tp) end
	local rg=Duel.SelectReleaseGroupCost(tp,s.cfilter,1,1,false,nil,nil,e,tp)
	e:SetLabel(rg:GetFirst():GetLevel())
	Duel.Release(rg,REASON_COST)
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,nil,1,tp,LOCATION_DECK)
end
function s.rescon(sg,e,tp,mg)
	return sg:GetSum(Card.GetLevel)<=e:GetLabel()
end
function s.operation(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if not c:IsRelateToEffect(e) then return end
	local ft=Duel.GetLocationCount(tp,LOCATION_MZONE)
	if ft<=0 then return end
	if Duel.IsPlayerAffectedByEffect(tp,CARD_BLUEEYES_SPIRIT) then ft=1 end
	local lv=e:GetLabel()
	local g=Duel.GetMatchingGroup(s.spfilter,tp,LOCATION_DECK,0,nil,e,tp,lv)
	if #g==0 then return end
	local sg=aux.SelectUnselectGroup(g,e,tp,1,ft,s.rescon,1,tp,HINTMSG_SPSUMMON)
	if #sg==0 then return end
	local fdg=Group.CreateGroup()
	for tc in sg:Iter() do
		if Duel.SpecialSummonStep(tc,0,tp,tp,false,false,POS_FACEUP_ATTACK|POS_FACEDOWN_DEFENSE) and tc:IsFacedown() then
			fdg:AddCard(tc)
		end
		c:SetCardTarget(tc)
	end
	Duel.SpecialSummonComplete()
	if #fdg>0 then
		Duel.ConfirmCards(1-tp,fdg)
	end
end
function s.desop(e,tp,eg,ep,ev,re,r,rp)
	local g=e:GetHandler():GetCardTarget():Filter(Card.IsLocation,nil,LOCATION_MZONE)
	Duel.Destroy(g,REASON_EFFECT)
end