def handle_startendtag(self, tag, attrs):
        """Function called for empty tags (e.g. <br />)"""
        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;'
Function called for empty tags (e.g. <br />)