react-native-Iap override 이슈 질문드립니다

#1 
    @Override
    protected List<ReactPackage> getPackages() {
      @SuppressWarnings("UnnecessaryLocalVariable")
      List<ReactPackage> packages = new PackageList(this).getPackages();
      // Packages that cannot be autolinked yet can be added manually here, for example:
      packages.add(new RNFirebaseAnalyticsPackage());
      packages.add(new RNFirebaseMessagingPackage());
      packages.add(new RNFirebaseNotificationsPackage());
      return packages;
    }

현재 이 코드인데

packages.add(packages.add(new RNIapPackage()); 를 추가하면

캡처
이런 에러가 뜨는데 getPackages()랑 중복 되서 그런걸까요? ㅠㅠ