fix Laundry Trap (#1990)

c79371769.lua

@@ -13,6 +13,7 @@ function c79371769.initial_effect(c)
 	e2:SetCode(EVENT_SUMMON_SUCCESS)
 	e2:SetProperty(EFFECT_FLAG_DELAY)
 	e2:SetCondition(c79371769.discon)
+	e2:SetCost(c79371769.discost)
 	e2:SetTarget(c79371769.distg)
 	e2:SetOperation(c79371769.disop)
 	c:RegisterEffect(e2)
@@ -35,6 +36,11 @@ end
 function c79371769.discon(e,tp,eg,ep,ev,re,r,rp)
 	return eg:IsExists(Card.IsControler,1,nil,tp)
 end
+function c79371769.discost(e,tp,eg,ep,ev,re,r,rp,chk)
+	local c=e:GetHandler()
+	if chk==0 then return c:GetFlagEffect(79371769)==0 end
+	c:RegisterFlagEffect(79371769,RESET_CHAIN,0,1)
+end
 function c79371769.distg(e,tp,eg,ep,ev,re,r,rp,chk)
 	if chk==0 then return Duel.IsPlayerCanDiscardDeck(tp,1) end
 	Duel.SetTargetPlayer(tp)