Undefined function or variable 'TOC' in DOM API

when i run following code.. i got error "Undefined function or variable 'TOC'

import mlreportgen.dom.*;
d = Document('mydoc','docx');
open(d);

title = append(d, Paragraph('My TOC Document'));
title.Bold = true;
title.FontSize = '28pt';

toc = append(d,TOC(2,' '));
toc.Style = {PageBreakBefore(true)};

h1 = append(d,Heading1('Chapter 1'));
h1.Style = {PageBreakBefore(true)};
p1 = append(d,Paragraph('Hello World'));

h2 = append(d,Heading2('Section 1.1'));
h2.Style = {PageBreakBefore(true)};
p2 = append(d,Paragraph('Another page'));

h3 = append(d,Heading3('My Subsection 1.1.a'));
p3 = append(d, Paragraph('My Level 3 Heading Text'));

close(d);
rptview(d.OutputPath);

what should i do to use TOC class in DOM API?**