Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If your opponent has 8 or more cards in their Graveyard: The ATK of all monsters your opponent currently controls become 0.
--墓地墓地の恨み
--Ghost of a Grudge
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	e1:SetProperty(EFFECT_FLAG_DAMAGE_STEP)
	e1:SetHintTiming(TIMING_DAMAGE_STEP)
	e1:SetCondition(s.condition)
	e1:SetTarget(s.target)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
end
function s.condition(e,tp,eg,ep,ev,re,r,rp)
	return aux.StatChangeDamageStepCondition() and Duel.GetFieldGroupCount(tp,0,LOCATION_GRAVE)>7
end
function s.filter(c)
	return c:IsFaceup() and c:GetAttack()>0
end
function s.target(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.filter,tp,0,LOCATION_MZONE,1,nil) end
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	local g=Duel.GetMatchingGroup(s.filter,tp,0,LOCATION_MZONE,nil)
	local tc=g:GetFirst()
	for tc in aux.Next(g) do
		local e1=Effect.CreateEffect(e:GetHandler())
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_SET_ATTACK_FINAL)
		e1:SetValue(0)
		e1:SetReset(RESET_EVENT|RESETS_STANDARD)
		tc:RegisterEffect(e1)
	end
end