Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Discard 2 cards from your hand. Select 1 face-up monster and change it to face-down Defense Position.
--闇の訪れ
--Darkness Approaches
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_POSITION)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetCost(s.cost)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
end
function s.cost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(Card.IsDiscardable,tp,LOCATION_HAND,0,2,e:GetHandler()) end
	Duel.DiscardHand(tp,Card.IsDiscardable,2,2,REASON_COST|REASON_DISCARD)
end
function s.filter(c)
	return c:IsFaceup() and c:IsCanTurnSet()
end
function s.target(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_FACEUP)
	local g=Duel.SelectTarget(tp,s.filter,tp,LOCATION_MZONE,LOCATION_MZONE,1,1,nil)
	Duel.SetOperationInfo(0,CATEGORY_POSITION,g,1,0,0)
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	if tc and tc:IsRelateToEffect(e) and tc:IsFaceup() then
		Duel.ChangePosition(tc,POS_FACEDOWN_DEFENSE)
	end
end