text: <?php
  
  declare(strict_types = 1);
  
  namespace iio\libmergepdf\Driver;
  
  use iio\libmergepdf\Source\SourceInterface;
  
  final class DefaultDriver implements DriverInterface
  {
      /**
       * @var DriverInterface
       */
      private $wrapped;
  
      public function __construct(DriverInterface $wrapped = null)
      {
          $this->wrapped = $wrapped ?: new Fpdi2Driver;
      }
  
      public function merge(SourceInterface ...$sources): string
      {
          return $this->wrapped->merge(...$sources);
      }
  }
  