public function apcu_regexp_delete($regexp = null)
    {
        if ($regexp && !preg_match("/^\/.+\/[a-z]*$/i", $regexp)) {
            throw new \RuntimeException("{$regexp} is not a valid Regex");
        }

        $code = new Code();
        $code->addStatement(sprintf(
            '$keys = new \APCIterator("user", %s, APC_ITER_KEY, 10);',
            var_export($regexp, true)
        ));
        $code->addStatement('return apc_delete($keys);');
        return $this->adapter->run($code);
    }