Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Banish 1 WATER monster from your GY; add 1 Level 4 or lower Sea Serpent monster from your Deck to your hand. You can only activate 1 "Deep Sea Aria" per turn.
--深海のアリア
--Deep Sea Aria
--scripted by AlphaKretin
local s,id=GetID()
function s.initial_effect(c)
	--activate
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_TOHAND+CATEGORY_SEARCH)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetCountLimit(1,id,EFFECT_COUNT_CODE_OATH)
	e1:SetCost(s.thcost)
	e1:SetTarget(s.thtg)
	e1:SetOperation(s.thop)
	c:RegisterEffect(e1)
end
function s.cfilter(c,tp)
	return c:IsAttribute(ATTRIBUTE_WATER) and c:IsAbleToRemoveAsCost() and aux.SpElimFilter(c,true)
end
function s.thcost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.cfilter,tp,LOCATION_MZONE|LOCATION_GRAVE,0,1,e:GetHandler(),tp) end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_REMOVE)
	local g=Duel.SelectMatchingCard(tp,s.cfilter,tp,LOCATION_MZONE|LOCATION_GRAVE,0,1,1,e:GetHandler(),tp)
	Duel.Remove(g,POS_FACEUP,REASON_COST)
end
function s.thfilter(c)
	return c:IsRace(RACE_SEASERPENT) and c:IsLevelBelow(4) and c:IsAbleToHand()
end
function s.thtg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.thfilter,tp,LOCATION_DECK,0,1,nil) end
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,nil,1,tp,LOCATION_DECK)
end
function s.thop(e,tp,eg,ep,ev,re,r,rp)
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_ATOHAND)
	local g=Duel.SelectMatchingCard(tp,s.thfilter,tp,LOCATION_DECK,0,1,1,nil)
	if #g>0 then
		Duel.SendtoHand(g,nil,REASON_EFFECT)
		Duel.ConfirmCards(1-tp,g)
	end
end