protected override async Task <object> OnPerform()
        {
            var response = await _restClient.CompleteOverrideLimit(
                _cacheManager.SaleNumber,
                _cacheManager.TillNumberForSale,
                _cacheManager.RegisterNumber);

            var data = await response.Content.ReadAsStringAsync();

            switch (response.StatusCode)
            {
            case HttpStatusCode.OK:
                var contract = new DeSerializer().MapCheckoutSummary(data);
                return(new Mapper().MapCheckoutSummary(contract));

            default:
                return(await HandleExceptions(response));
            }
        }