static List<Card> checkStrait(List<Card> cards) {
        boolean skipIter;
        Card temp;
        
        skipIter = true;
        temp = cards.get(0);

        Collections.sort(cards, new ValueComparator());
        for (Card card: cards) {
            // skip first iteration
            if (skipIter == true) {
                skipIter = false;
                continue;
            }

            if (card.value - temp.value != 1) {
                cards = null;
                break;
            }
        }
        return cards;
    }