private static ArrayList<String> hasProperty(int maxChoices, CardList cards, ArrayList<String> colors) {
        for (Card c : cards) {
            // For each card, go through all the colors and if the card is that color, add
            for (String col : Constant.Color.onlyColors) {
                if (c.isColor(col) && !colors.contains(col)) {
                    colors.add(col);
                    if (colors.size() == maxChoices)
                        break;
                }
            }
        }
        return colors;
    }