public async Task <IEnumerable <Customer> > getCustomers()
        {
            using (var client = new HttpClient())
            {
                client.BaseAddress = new Uri("https://demo0636357.mockable.io/");
                client.DefaultRequestHeaders.Accept.Clear();
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

                HttpResponseMessage response = await client.GetAsync("customers/");

                if (response.IsSuccessStatusCode)
                {
                    return(_jsonParser.ParseCustomers(response));
                }
            }
            return(null);
        }