Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
1 Level 4 or lower Dragon monster You cannot Special Summon monsters, except Dragon monsters. During your Main Phase: You can Special Summon 1 Dragon monster from your hand or Deck to your zone that 2 or more Link Monsters point to. You can only use this effect of "Guardragon Elpy" once per turn. You can only Special Summon "Guardragon Elpy(s)" once per turn.
--守護竜エルピィ
--Guardragon Elpy
--Scripted by AlphaKretin
local s,id=GetID()
function s.initial_effect(c)
	c:SetSPSummonOnce(id)
	--link summon
	c:EnableReviveLimit()
	Link.AddProcedure(c,s.matfilter,1,1)
	--cannot special summon
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_FIELD)
	e1:SetProperty(EFFECT_FLAG_PLAYER_TARGET)
	e1:SetCode(EFFECT_CANNOT_SPECIAL_SUMMON)
	e1:SetRange(LOCATION_MZONE)
	e1:SetTargetRange(1,0)
	e1:SetTarget(s.sumlimit)
	c:RegisterEffect(e1)
	--special summon
	local e2=Effect.CreateEffect(c)
	e2:SetDescription(aux.Stringid(id,0))
	e2:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e2:SetType(EFFECT_TYPE_IGNITION)
	e2:SetCountLimit(1,id)
	e2:SetRange(LOCATION_MZONE)
	e2:SetTarget(s.sptg)
	e2:SetOperation(s.spop)
	c:RegisterEffect(e2)
end
function s.matfilter(c,lc,sumtype,tp)
	return c:IsLevelBelow(4) and c:IsRace(RACE_DRAGON,lc,sumtype,tp)
end
function s.sumlimit(e,c)
	return not c:IsRace(RACE_DRAGON)
end
function s.filter(c,e,tp,zone)
	return c:IsRace(RACE_DRAGON) and c:IsCanBeSpecialSummoned(e,0,tp,false,false,POS_FACEUP,tp,zone)
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk)
	local zone=Duel.GetZoneWithLinkedCount(2,tp)&ZONES_MMZ
	if chk==0 then return Duel.IsExistingMatchingCard(s.filter,tp,LOCATION_HAND|LOCATION_DECK,0,1,nil,e,tp,zone) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,nil,1,tp,LOCATION_HAND|LOCATION_DECK)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	local zone=Duel.GetZoneWithLinkedCount(2,tp)&ZONES_MMZ
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g=Duel.SelectMatchingCard(tp,s.filter,tp,LOCATION_HAND|LOCATION_DECK,0,1,1,nil,e,tp,zone)
	if #g>0 and zone~=0 then
		Duel.SpecialSummon(g,0,tp,tp,false,false,POS_FACEUP,zone)
	end
end