Argument 1 passed to think\cache\Driver::unserialize() must be of the type string, boolean given, called in

#0 [0]TypeError in Driver.php line 242

Argument 1 passed to think\cache\Driver::unserialize() must be of the type string, boolean given, called in /www/wwwroot/xxxxx.com/vendor/topthink/framework/src/think/cache/driver/File.php on line 139

233. return $serialize($data);

234. }

235. 

236. /**

237. * 反序列化数据

238. * @access protected

239. * @param string $data 缓存数据

240. * @return mixed

241. */

242. protected function unserialize(string $data)

243. {

244. if (is_numeric($data)) {

245. return $data;

246. }

247. 

248. $unserialize = $this->options['serialize'][1] ?? "unserialize";

249. 

250. return $unserialize($data);

251. }