Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
If you Ritual Summon exactly 1 DARK Ritual Monster with a card effect that requires use of monsters, this card can be used as the entire requirement.
--儀式の供物
--Ritual Raven
local s,id=GetID()
function s.initial_effect(c)
	--ritual level
	Ritual.AddWholeLevelTribute(c,aux.FilterBoolFunction(Card.IsAttribute,ATTRIBUTE_DARK))
end