private static string _BetFairLogin(string user, string pass)
        {
            string uri = "https://api.mountbet.com/v1.0/login";

            string appKey = Properties.Settings.Default.AppKey;

            string myParameters = String.Format("username={0}&password={1}", user, pass);

            var data = new { username = user, password = pass };
            var paramsJson = Newtonsoft.Json.JsonConvert.SerializeObject(data);

            WebClient client = new WebClient();

            client.Headers[HttpRequestHeader.ContentType] = "application/json";
            client.Headers[HttpRequestHeader.Accept] = "application/json";
            client.Headers["X-Application"] = appKey;

            string loginResponseStr = client.UploadString(uri, paramsJson);

            LoginResponse loginResponse = Newtonsoft.Json.JsonConvert.DeserializeObject<LoginResponse>(loginResponseStr);

            if (loginResponse.Token != null)
            {
                return loginResponse.Token;
            }
            else
            {
                return null;
            }
        }