Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
1 "Gem-Knight" monster + 1 Aqua-Type monster Must first be Fusion Summoned. When this card is sent from the field to the Graveyard: Return all Set Spell and Trap Cards on the field to the hand.
--ジェムナイト・アメジス
--Gem-Knight Amethyst
local s,id=GetID()
function s.initial_effect(c)
	--fusion material
	c:EnableReviveLimit()
	Fusion.AddProcMix(c,true,true,aux.FilterBoolFunctionEx(Card.IsSetCard,SET_GEM_KNIGHT),aux.FilterBoolFunctionEx(Card.IsRace,RACE_AQUA))
	--spsummon condition
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_SINGLE)
	e2:SetProperty(EFFECT_FLAG_CANNOT_DISABLE+EFFECT_FLAG_UNCOPYABLE)
	e2:SetCode(EFFECT_SPSUMMON_CONDITION)
	e2:SetValue(s.splimit)
	c:RegisterEffect(e2)
	--to hand
	local e3=Effect.CreateEffect(c)
	e3:SetDescription(aux.Stringid(id,0))
	e3:SetCategory(CATEGORY_TOHAND)
	e3:SetType(EFFECT_TYPE_SINGLE+EFFECT_TYPE_TRIGGER_F)
	e3:SetCode(EVENT_TO_GRAVE)
	e3:SetCondition(s.thcon)
	e3:SetTarget(s.thtg)
	e3:SetOperation(s.thop)
	c:RegisterEffect(e3)
end
s.listed_series={SET_GEM_KNIGHT}
s.material_setcode={SET_GEM,SET_GEM_KNIGHT}
function s.splimit(e,se,sp,st)
	return not e:GetHandler():IsLocation(LOCATION_EXTRA) or (st&SUMMON_TYPE_FUSION)==SUMMON_TYPE_FUSION
end
function s.thcon(e,tp,eg,ep,ev,re,r,rp)
	return (e:GetHandler():GetPreviousLocation()&LOCATION_ONFIELD)~=0
end
function s.thtg(e,tp,eg,ep,ev,re,r,rp,chk,chkc)
	if chk==0 then return true end
	local g=Duel.GetMatchingGroup(Card.IsFacedown,tp,LOCATION_SZONE,LOCATION_SZONE,nil)
	Duel.SetOperationInfo(0,CATEGORY_TOHAND,g,#g,0,0)
end
function s.thop(e,tp,eg,ep,ev,re,r,rp)
	local g=Duel.GetMatchingGroup(Card.IsFacedown,tp,LOCATION_SZONE,LOCATION_SZONE,nil)
	Duel.SendtoHand(g,nil,REASON_EFFECT)
end