Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Equip only to a Dragon-Type monster. It cannot be destroyed by battle or by card effects. Neither player takes any battle damage from attacks involving it.
--ドラゴン・シールド
--Dragon Shield
local s,id=GetID()
function s.initial_effect(c)
	aux.AddEquipProcedure(c,nil,aux.FilterBoolFunction(Card.IsRace,RACE_DRAGON))
	--
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_EQUIP)
	e3:SetCode(EFFECT_INDESTRUCTABLE_BATTLE)
	e3:SetValue(1)
	c:RegisterEffect(e3)
	local e4=e3:Clone()
	e4:SetCode(EFFECT_INDESTRUCTABLE_EFFECT)
	c:RegisterEffect(e4)
	local e5=e3:Clone()
	e5:SetCode(EFFECT_NO_BATTLE_DAMAGE)
	c:RegisterEffect(e5)
	local e6=e3:Clone()
	e6:SetCode(EFFECT_AVOID_BATTLE_DAMAGE)
	c:RegisterEffect(e6)
end