code: private function getDafaultCategories(array $mainVariation)
      {
          $defaultCategories = [];
  
          foreach ($mainVariation['variationDefaultCategory'] as $category) {
              $categoryIdentity = $this->identityService->findOneBy([
                  'adapterIdentifier' => (string) $category['branchId'],
                  'adapterName' => PlentymarketsAdapter::NAME,
                  'objectType' => Category::TYPE,
              ]);
  
              if (null === $categoryIdentity) {
                  $this->logger->notice('missing mapping for category', ['category' => $category]);
  
                  continue;
              }
  
              $defaultCategories[] = $categoryIdentity->getObjectIdentifier();
          }
  
          return $defaultCategories;
      }
docs: @param array $mainVariation
  
  @return array