MatthiasMullie\Scrapbook\Psr6\Pool::deleteItems PHP Method

    public function deleteItems(array $keys)
    {
        foreach ($keys as $key) {
            $this->assertValidKey($key);
            unset($this->deferred[$key]);
        }
        $this->store->deleteMulti($keys);
        // as long as the item is gone from the cache (even if it never existed
        // and delete failed because of that), we should return `true`
        return true;
    }