var response: LiveData<TopHeadlineResponse?>
 response = Transformations.switchMap(loadData){
            switchMapForApiResponse(newsRepository.getTopHeadlines(), doOnSuccess = {
                showLoader.value = View.GONE
                return@switchMapForApiResponse it
            }, doOnSubscribe = {
                showLoader.value = View.VISIBLE
            }, doOnError = {
                showLoader.value = View.GONE
})