Illuminate\Database\Eloquent\Model::saved PHP Method

    public static function saved($callback, $priority = 0)
    {
        static::registerModelEvent('saved', $callback, $priority);
    }

 public function process(Attachment $attachment)
 {
     $this->attachment = $attachment;
     $this->attach($attachment);
     $this->attachment->saved(function (Attachment $attachment) {
         $this->getFinder()->useDisk($attachment->disk);
         $this->apply($attachment);
     });
 }