The List class and it's children have been structured to
      allow full nesting of either regular Python data types, (e.g.,
      lists of lists of strings) or HTMLgen objects. For example, an
      OrderedList class can contain an instance of the List class,
      ImageBulletList class and DefinitionList class. Added in version
      2.0.6 is the capability to render the list into multiple
      columns. Just set the columns attribute to a number
      greater than one and it will use that many columns. Also added
      is the ability to assign a background color through the use of
      the bgcolor attribute.
        
The Netscape Navigator extension type tag is
      supported as an attribute of the List and OrderedList classes
      and can be set as keyword parameters (although they have
      different meanings).  In List instances you can set the
      type='disk' | 'circle' | 'square' to hardwire the
      style of bullet used. In OrderedList instances you can set
      type='A' | 'a' | 'I' | 'i' to alter the numbering from
      Arabic to respectively: capital letters, small letters, Roman
      numerals, small Roman numerals.
      
Normal list operations apply to all the classes in this family as the base class inherits from the UserList class provided in the core distribution.
The rendered HTML output should also exhibit indentation proportional to the level of list nesting.
Below is some example output. See the HTMLtest.py script for the source code which generated it.