I took a look at the module and its doc.  It is based on a 1980s model of document processing that has been somewhat superseded by html, xml, and pdf.  The module itself has been pretty well superseded by stdlib and external moudles.  IDLE, for instance, displays idle.html in a tkinter Text widget about 160 lines by subclassing htmlparser.  

One obsolescent 'feature' is that fonts are defined by (size, italic, bold, teletype), where 'teletype' is a bool of undefined meaning.  There is no way I saw to designate a font family like 'Source Code Pro' or 'Monaco'.

Since the module is unmaintained and frozen, anyone importing it can incorporate whatever class code they need.