Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Target 1 face-up monster you control and declare a Level between 1 and 3; it becomes that Level.
--下降潮流
--Falling Current
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_LVCHANGE)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetProperty(EFFECT_FLAG_CARD_TARGET)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
end
function s.filter(c)
	return c:IsFaceup() and c:HasLevel() and not c:IsLevel(0)
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chkc then return chkc:IsLocation(LOCATION_MZONE) and chkc:IsControler(tp) and s.filter(chkc) end
	if chk==0 then return Duel.IsExistingTarget(s.filter,tp,LOCATION_MZONE,0,1,nil) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_FACEUP)
	local g=Duel.SelectTarget(tp,s.filter,tp,LOCATION_MZONE,0,1,1,nil)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_LVRANK)
	local lv=Duel.AnnounceLevel(tp,1,3,g:GetFirst():GetLevel())
	Duel.SetTargetParam(lv)
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	local tc=Duel.GetFirstTarget()
	local lv=Duel.GetChainInfo(0,CHAININFO_TARGET_PARAM)
	if tc and tc:IsFaceup() and tc:IsRelateToEffect(e) then
		local e1=Effect.CreateEffect(e:GetHandler())
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_CHANGE_LEVEL)
		e1:SetValue(lv)
		e1:SetReset(RESET_EVENT|RESETS_STANDARD)
		tc:RegisterEffect(e1)
	end
end