code: def handle_startendtag(self, tag, attrs):
          
          if tag.lower() in self.allowed_tag_whitelist:
              self.result += '<' + tag
              for (attr, value) in attrs:
                  if attr.lower() in self.allowed_attribute_whitelist:
                      self.result += ' %s="%s"' % \
                          (attr, self.handle_attribute_value(value))
              self.result += ' />'
          else:
              if self.render_unallowed_tags:
                  self.result += '&lt;' + cgi.escape(tag)
                  for (attr, value) in attrs:
                      self.result += ' %s="%s"' % \
                          (attr, cgi.escape(value, True))
                  self.result += ' /&gt;'
docs: Function called for empty tags (e.g. <br />)