Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
This card can attack twice during the same Battle Phase.
--ツインヘデッド・ビースト
--Twinheaded Beast
local s,id=GetID()
function s.initial_effect(c)
	--multi attack
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_SINGLE)
	e1:SetCode(EFFECT_EXTRA_ATTACK)
	e1:SetValue(1)
	c:RegisterEffect(e1)
end