presto-verifier/src/main/java/io/prestosql/verifier/Validator.java/Validator/rowComparator
class Validator:    private static Comparator<List<Object>> rowComparator(int precision)
    {
        Comparator<Object> comparator = Ordering.from(columnComparator(precision)).nullsFirst();
        return (a, b) -> {
            if (a.size() != b.size()) {
                return Integer.compare(a.size(), b.size());
            }
            for (int i = 0; i < a.size(); i++) {
                int r = comparator.compare(a.get(i), b.get(i));
                if (r != 0) {
                    return r;
                }
            }
            return 0;
        };
    }