private static boolean discardTrigger(AbilityFactory af, SpellAbility sa, boolean mandatory) {
        if (!ComputerUtil.canPayCost(sa))
            return false;

        Target tgt = af.getAbTgt();
        if (tgt != null) {
            if (!discardTargetAI(af)) {
                if (mandatory && AllZone.getComputerPlayer().canTarget(af.getHostCard()))
                    tgt.addTarget(AllZone.getComputerPlayer());
                else
                    return false;
            }
        }

        return true;
    }// discardTrigger()