presto-spi/src/main/java/io/prestosql/spi/predicate/Marker.java/Marker/lesserAdjacent
class Marker:    public Marker lesserAdjacent()
    {
        if (!valueBlock.isPresent()) {
            throw new IllegalStateException("No marker adjacent to unbounded");
        }
        switch (bound) {
            case BELOW:
                throw new IllegalStateException("No lesser marker adjacent to a BELOW bound");
            case EXACTLY:
                return new Marker(type, valueBlock, Bound.BELOW);
            case ABOVE:
                return new Marker(type, valueBlock, Bound.EXACTLY);
            default:
                throw new AssertionError("Unsupported type: " + bound);
        }
    }