def extend(self):
        """Extend the OAuth token."""
        graph = GraphAPI()

        response = graph.get('oauth/access_token',
            client_id = FACEBOOK_APPLICATION_ID,
            client_secret = FACEBOOK_APPLICATION_SECRET_KEY,
            grant_type = 'fb_exchange_token',
            fb_exchange_token = self.token
        )

        components = parse_qs(response)

        self.token = components['access_token'][0]
        self.expires_at = now() + timedelta(seconds = int(components['expires'][0]))

        self.save()
Extend the OAuth token.