Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
At the end of the Damage Step, if this card battled an opponent's monster: Change that monster to face-down Defense Position.
--ゴロゴル
--Gonogo
local s,id=GetID()
function s.initial_effect(c)
	--pos
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_POSITION)
	e1:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e1:SetCode(EVENT_DAMAGE_STEP_END)
	e1:SetTarget(s.target)
	e1:SetOperation(s.operation)
	c:RegisterEffect(e1)
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	local tg=e:GetHandler():GetBattleTarget()
	if chk==0 then return tg and tg:IsRelateToBattle() end
	Duel.SetOperationInfo(0,CATEGORY_POSITION,tg,1,0,0)
end
function s.operation(e,tp,eg,ep,ev,re,r,rp)
	local bc=e:GetHandler():GetBattleTarget()
	if bc:IsRelateToBattle() and bc:IsFaceup() then
		Duel.ChangePosition(bc,POS_FACEDOWN_DEFENSE)
	end
end