renderLink() is called to render a link to the DP

def renderLink(self, relpath=""):
        """renderLink() is called to render a link to the DP
        """
        # return from cache if available
        cachekey, html = self.checkCache('Link', relpath)
        if html is not None:
            return html
        # else regenerate
        html = CachingRenderer.renderLink(self, relpath)
        if self.headerfile is not None:
            html += """ (<A HREF="%s">header</A>)""" % quote_url(relpath + self.headerfile)
        # save to cache
        return self.writeCache(cachekey, html)