serialization

{'html': ('HTML',
          '-//W3C//DTD HTML 4.01 Transitional//EN',
          'http://www.w3.org/TR/html4/loose.dtd'),
 'html-frameset': ('HTML',
                   '-//W3C//DTD HTML 4.01 Frameset//EN',
                   'http://www.w3.org/TR/html4/frameset.dtd'),
 'html-frameset-quirks': ('HTML', '-//W3C//DTD HTML 4.01 Frameset//EN'),
 'html-quirks': ('HTML', '-//W3C//DTD HTML 4.01 Transitional//EN'),
 'html-strict': ('HTML',
                 '-//W3C//DTD HTML 4.01//EN',
                 'http://www.w3.org/TR/html4/strict.dtd'),
 'wml': ('wml',
         '-//WAPFORUM//DTD WML 1.1//EN',
         'http://www.wapforum.org/DTD/wml_1.1.xml'),
 'xhtml': ('html',
           '-//W3C//DTD XHTML 1.0 Transitional//EN',
           'http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd'),
 'xhtml-frameset': ('html',
                    '-//W3C//DTD XHTML 1.0 Frameset//EN',
                    'http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd'),
 'xhtml-strict': ('html',
                  '-//W3C//DTD XHTML 1.0 Strict//EN',
                  'http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd')}