Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Special Summon this card in Defense Position as an Effect Monster (Machine/EARTH/Level 4/ATK 0/DEF 2000). (This card is also still a Trap.) While you control "Green Gadget", "Red Gadget", and "Yellow Gadget", this card gains 3000 ATK.
--機動砦 ストロング・ホールド
--Stronghold the Moving Fortress
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
end
s.listed_names={41172955,86445415,13839120}
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.GetLocationCount(tp,LOCATION_MZONE)>0
		and Duel.IsPlayerCanSpecialSummonMonster(tp,id,0,TYPE_MONSTER|TYPE_EFFECT,0,2000,4,RACE_MACHINE,ATTRIBUTE_EARTH) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,e:GetHandler(),1,0,0)
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if not c:IsRelateToEffect(e) then return end
	if Duel.GetLocationCount(tp,LOCATION_MZONE)<=0
		or not Duel.IsPlayerCanSpecialSummonMonster(tp,id,0,TYPE_MONSTER|TYPE_EFFECT,0,2000,4,RACE_MACHINE,ATTRIBUTE_EARTH) then return end
	c:AddMonsterAttribute(TYPE_TRAP+TYPE_EFFECT)
	Duel.SpecialSummonStep(c,0,tp,tp,true,false,POS_FACEUP_DEFENSE)
	c:AddMonsterAttributeComplete()
	--update attack
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetProperty(EFFECT_FLAG_SINGLE_RANGE)
	e1:SetRange(LOCATION_MZONE)
	e1:SetCode(EFFECT_UPDATE_ATTACK)
	e1:SetValue(3000)
	e1:SetCondition(s.atkcon)
	e1:SetReset(RESET_EVENT|RESETS_STANDARD)
	c:RegisterEffect(e1,true)
	Duel.SpecialSummonComplete()
end
function s.atkcon(e)
	local tp=e:GetHandlerPlayer()
	return Duel.IsExistingMatchingCard(aux.FaceupFilter(Card.IsCode,41172955),tp,LOCATION_ONFIELD,0,1,nil)
		and Duel.IsExistingMatchingCard(aux.FaceupFilter(Card.IsCode,86445415),tp,LOCATION_ONFIELD,0,1,nil)
		and Duel.IsExistingMatchingCard(aux.FaceupFilter(Card.IsCode,13839120),tp,LOCATION_ONFIELD,0,1,nil)
end