Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If this card is in the GY and you control no cards: You can Special Summon both this card, and 1 Level 4 or lower Dragon monster from your hand, in Defense Position, but banish this card when it leaves the field. You can only use this effect of "Background Dragon" once per turn.
--バックグランド・ドラゴン
--Background Dragon
local s,id=GetID()
function s.initial_effect(c)
	--Special summon itself (GY) and 1 level 4 or lower dragon monster (hand)
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_SPECIAL_SUMMON)
	e1:SetType(EFFECT_TYPE_IGNITION)
	e1:SetRange(LOCATION_GRAVE)
	e1:SetCountLimit(1,id)
	e1:SetCondition(s.spcon)
	e1:SetTarget(s.sptg)
	e1:SetOperation(s.spop)
	c:RegisterEffect(e1)
end
function s.spcon(e,tp,eg,ep,ev,re,r,rp)
	return Duel.GetFieldGroupCount(tp,LOCATION_ONFIELD,0)==0
end
function s.filter(c,e,tp)
	return c:IsLevelBelow(4) and c:IsRace(RACE_DRAGON) and c:IsCanBeSpecialSummoned(e,0,tp,false,false)
end
function s.sptg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return not Duel.IsPlayerAffectedByEffect(tp,CARD_BLUEEYES_SPIRIT)
		and Duel.GetLocationCount(tp,LOCATION_MZONE)>1
		and e:GetHandler():IsCanBeSpecialSummoned(e,0,tp,false,false)
		and Duel.IsExistingMatchingCard(s.filter,tp,LOCATION_HAND,0,1,e:GetHandler(),e,tp) end
	Duel.SetOperationInfo(0,CATEGORY_SPECIAL_SUMMON,e:GetHandler(),2,tp,LOCATION_HAND|LOCATION_GRAVE)
end
function s.spop(e,tp,eg,ep,ev,re,r,rp)
	local c=e:GetHandler()
	if not c:IsRelateToEffect(e) then return end
	if Duel.IsPlayerAffectedByEffect(tp,CARD_BLUEEYES_SPIRIT) then return end
	if Duel.GetLocationCount(tp,LOCATION_MZONE)<2 then return end
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_SPSUMMON)
	local g=Duel.SelectMatchingCard(tp,s.filter,tp,LOCATION_HAND,0,1,1,c,e,tp)
	if #g>0 then
		g:AddCard(c)
		if Duel.SpecialSummon(g,0,tp,tp,false,false,POS_FACEUP_DEFENSE)>0 then
			--Banish it if it leaves the field
			local e1=Effect.CreateEffect(c)
			e1:SetDescription(3300)
			e1:SetType(EFFECT_TYPE_SINGLE)
			e1:SetCode(EFFECT_LEAVE_FIELD_REDIRECT)
			e1:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_CLIENT_HINT)
			e1:SetReset(RESET_EVENT|RESETS_REDIRECT)
			e1:SetValue(LOCATION_REMOVED)
			c:RegisterEffect(e1,true)
		end
	end
end