Spatie\Backup\Exceptions\InvalidBackupDestination::diskNotSet PHP Method

    public static function diskNotSet() : InvalidBackupDestination
    {
        return new static('There is no disk set for the backup destination');
    }

 public function write(string $file)
 {
     if (is_null($this->disk)) {
         throw InvalidBackupDestination::diskNotSet();
     }
     $destination = $this->backupName . '/' . pathinfo($file, PATHINFO_BASENAME);
     $handle = fopen($file, 'r+');
     $this->disk->getDriver()->writeStream($destination, $handle);
 }