Get web.ctx object for the Template helper

def _get_ctx(self):
        """ Get web.ctx object for the Template helper """
        if self._WEB_CTX_KEY not in web.ctx:
            web.ctx[self._WEB_CTX_KEY] = {
                "javascript": {"footer": [], "header": []},
                "css": []}
        return web.ctx.get(self._WEB_CTX_KEY)