code: public function load(ObjectManager $manager)
      {
          $new = $this->generateContentTypeNews();
          $manager->persist($new);
  
          $car = $this->generateContentTypeCar();
          $manager->persist($car);
  
          $customer = $this->generateContentTypeCustomer();
          $manager->persist($customer);
  
          $manager->flush();
      }
docs: Load data fixtures with the passed EntityManager
  
  @param ObjectManager $manager