public function upload($file, $key)
    {
        if (! $file || ! $this->isValidKey($key))
            return;

        $fileName = $file->getClientOriginalName();
        $pathinfo = pathinfo($fileName);

        $this->deleteStored($key);

        Storage::putFileAs($this->getStoragePath(), $file, $key . '.' . $pathinfo['extension']);
    }