code: public function load(ObjectManager $manager)
      {
          /*
           * creates a Media of type mm_media.type.image
           */
          $media = new Media();
          $media->setAuthor('Max Mustermann');
          $media->setCopyright('Mustermann gGmbH');
          $media->setDescription('This is a Media description.');
          $media->setName('Media-Name');
  
          $media->setMediaTypeMetadata(array('foo' => 'bar'));
          $media->setMediaType(new ImageMediaType());
          $media->setMediaTypeReference('image.jpg');
  
          /*
           * creates a MediaSortable
           */
          $mediaSortable1 = new MediaSortable();
          $mediaSortable1->setPosition(1);
          $mediaSortable1->setMedia($media);
  
          $this->addReference('mediaSortable-1', $mediaSortable1);
  
          $manager->persist($mediaSortable1);
  
          $manager->flush();
      }
docs: {@inheritdoc}