private OAuthSession session;

  public SlackClient(SlackApi slackApi) {
    this.slackApi = slackApi;
  }

  /** Shows a browser URL to authorize this app to act as this user. */
  public void requestOauthSession(String scopes, String team) throws Exception {
    if (sessionFactory == null) {
      sessionFactory = new OAuthSessionFactory(slackApi);
      sessionFactory.start();
    }