presto-parser/src/main/java/io/prestosql/sql/tree/FrameBound.java/FrameBound/getChildren
class FrameBound:    @Override
    public List<Node> getChildren()
    {
        ImmutableList.Builder<Node> nodes = ImmutableList.builder();
        value.ifPresent(nodes::add);
        return nodes.build();
    }