UserVoice OAuth helper for SSO

UserVoiceOAuthHelper.cs

using System;
using RestSharp;
using RestSharp.Authenticators;

namespace UserVoice.Api
{
    public class UserVoiceOAuthToken
    {
        public string OauthToken { get; set; }
        public string OauthTokenSecret { get; set; }
    }

    public class UserVoiceOAuthHelper
    {
        private readonly string url;
        private readonly string consumerKey;
        private readonly string consumerSecret;

        public UserVoiceOAuthHelper(string url, string consumerKey, string consumerSecret)
        {
            this.url = url;     // http://{youraccount}.uservoice.com/api/v1/
            this.consumerKey = consumerKey;
            this.consumerSecret = consumerSecret;
        }

        public UserVoiceOAuthToken GetRequestToken()
        {
            var oauth = OAuth1Authenticator.ForRequestToken(consumerKey, consumerSecret);
            var client = new RestClient(url) { Authenticator = oauth };
            var request = new RestRequest("oauth/request_token.json", Method.POST) { RootElement = "token" };
            var response = client.Execute<UserVoiceOAuthToken>(request);

            if (response.Data == null)
                throw new Exception(response.ErrorMessage, response.ErrorException);

            return response.Data;
        }

        public UserVoiceOAuthToken Authorize(string sso, UserVoiceOAuthToken requestToken)
        {
            var oauth = OAuth1Authenticator.ForProtectedResource(consumerKey, consumerSecret, null, null);
            var client = new RestClient(url) { Authenticator = oauth };
            var request = new RestRequest("oauth/authorize.json", Method.POST) { RootElement = "token" };
            request.AddParameter("sso", sso);   // DO NOT URL ENCODE THE SSO TOKEN!!!
            request.AddParameter("request_token", requestToken.OauthToken);
            var response = client.Execute<UserVoiceOAuthToken>(request);

            if (response.Data == null)
                throw new Exception(response.ErrorMessage, response.ErrorException);

            return response.Data;
        }
    }
}