private static string GetString(string url, string accessToken)
        {
            using (var c = new WebClient())
            {
                c.Headers[HttpRequestHeader.Authorization] =
                    String.Format(SpApiConstants.RequestHeaders.AUTHORIZATIONTEMPLATE, accessToken);
                c.Headers[HttpRequestHeader.Accept] = SpApiConstants.RequestHeaders.JSON_CONTENT;

                try
                {
                    var results = c.DownloadString(url);
                    return(results);
                }
                catch (WebException exception)
                {
                    var reason = ExceptionService.GetFailureReason(exception);
                    throw ExceptionService.WebExceptionHandler(exception, reason);
                }
            }
        }