code: def init_app(self, app):
          
          app.add_url_rule(self.request_token_url, view_func=self.request_token,
                           methods=[u'POST'])
          app.add_url_rule(self.access_token_url, view_func=self.access_token,
                           methods=[u'POST'])
          app.add_url_rule(self.register_url, view_func=self.register,
                           methods=[u'GET', u'POST'])
          app.add_url_rule(self.authorize_url, view_func=self.authorize,
                           methods=[u'GET', u'POST'])
docs: Setup the 4 default routes.