static List<Card> getTopCards(List<List<Card>> sets) {
        Card topA;
        Card topB;
        Card top;
        List<Card> tops;
        List<Card> setA;
        List<Card> setB;
        
        setA = sets.get(0);
        setB = sets.get(1);
        topA = null;
        topB = null;
        tops = new ArrayList<>();
        
        top = null;
        if (setA != null) {
            topA = setA.get(setA.size()-1);
            top = topA;
            
            if (setB != null) {
                topB = setB.get(setB.size()-1);
            }
        }
        
        tops.add(topA);
        tops.add(topB);
        
        return tops;
    }