class DataManager {

    public Single<List<Transaction>> getTransactions(String accountId) {
        String token = buildAuthorization();
        return mMondroidService.getTransactions(token, accountId, "merchant")
                .map(new Func1<MondroidService.TransactionResponse, List<Transaction>>() {
                    @Override
                    public List<Transaction> call(MondroidService.TransactionResponse transactionResponse) {
                        return transactionResponse.transactions;
                    }
                });
    }

    @Inject public  DataManager(MondroidService mondroidService, PreferencesHelper preferencesHelper);

}