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

    public function deleteItem($key)
    {
        $this->assertValidKey($key);
        $this->store->delete($key);
        unset($this->deferred[$key]);
        // 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;
    }