code: def handle_starttag(self, tag, attrs):
          
          self.log.debug( u'Encountered a start tag: {0} {1}'.format(tag, attrs) )
          if tag in self.sanitizelist:
              self.level += 1
              return
          if self.isNotPurify or tag in self.whitelist_keys:
              attrs = self.__attrs_str(tag, attrs)
              attrs = ' ' + attrs if attrs else ''
              tmpl = u'<%s%s />' if tag in self.unclosedTags and self.isStrictHtml else u'<%s%s>'
              self.data.append( tmpl % (tag, attrs,) )
docs: Handler of starting tag processing (overrided, private)