V4.0 后台网址分类出现如下错误

    function edit($data)
    {
        $result = $this->isUpdate(true)->allowField(true)->save($data);
        if ($result) {
            return true;
        } else {
            return false;
        }
    }
    public function catetree($sn)
    {
        $tptc = $this->where(array('sn'=>$sn))->order('sort desc')->select();
        return $this->sort($tptc);
    }
    public function sort($data, $tid = 0, $level = 0)
    {
        static $arr = array();
        foreach ($data as $k => $v) {
            if ($v['tid'] == $tid) {