Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Discard 1 card; send 4 Reptile monsters from your Deck to the GY.
--スネーク・レイン
--Snake Rain
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetCategory(CATEGORY_TOGRAVE)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	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,0,1,e:GetHandler()) end
	Duel.DiscardHand(tp,Card.IsDiscardable,1,1,REASON_COST|REASON_DISCARD)
end
function s.tgfilter(c)
	return c:IsRace(RACE_REPTILE) and c:IsMonster() and c:IsAbleToGrave()
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.tgfilter,tp,LOCATION_DECK,0,4,nil) end
	Duel.SetOperationInfo(0,CATEGORY_TOGRAVE,nil,4,tp,LOCATION_DECK)
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	local g=Duel.GetMatchingGroup(s.tgfilter,tp,LOCATION_DECK,0,nil)
	if #g>=4 then
		Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_TOGRAVE)
		local sg=g:Select(tp,4,4,nil)
		Duel.SendtoGrave(sg,REASON_EFFECT)
	end
end