getUserUseCase.execute().flatMap { [weak self] user -> Observable<[Product]> in
    return self?.getFavoriteProductsUseCase.execute(GetFavoriteProductsRequestValues(userId: user.id))
}.subscribe(onNext: { [weak self] products in
    self?.ui.showProducts(products.compactMap { return $0.transformToUI })
}, onError: { error in
    self?.ui.showError()
}, onCompleted: {
}).disposed(by: disposeBag)