Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
When this card is Normal Summoned: You can target 1 monster on the field; change that target to face-up Defense Position.
--暗黒ブラキ
--Black Brachios
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_O)
	e1:SetCode(EVENT_SUMMON_SUCCESS)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetTarget(s.postg)
	e1:SetOperation(s.posop)
	c:RegisterEffect(e1)
end
function s.filter(c)
	return not c:IsPosition(POS_FACEUP_DEFENSE) and c:IsCanChangePosition()
end
function s.postg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsLocation(LOCATION_MZONE) and s.filter(chkc) end
	if chk==0 then return Duel.IsExistingTarget(s.filter,tp,LOCATION_MZONE,LOCATION_MZONE,1,nil) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_POSCHANGE)
	Duel.SelectTarget(tp,s.filter,tp,LOCATION_MZONE,LOCATION_MZONE,1,1,nil)
end
function s.posop(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc:IsRelateToEffect(e) and not tc:IsPosition(POS_FACEUP_DEFENSE) then
		Duel.ChangePosition(tc,POS_FACEUP_DEFENSE)
	end
end