code: public function create(Specification $spec, QueryBuilder $qb)
      {
          if (!$spec instanceof Not) {
              throw new \InvalidArgumentException();
          }
  
          $firstPartFactory = $this->registry->getFactory($spec->getWrappedSpecification());
  
          return $qb->query()->bool()
              ->addMustNot($firstPartFactory->create($spec->getWrappedSpecification(), $qb))
          ;
      }
docs: {inheritdoc}