/**
  * Save an access token to the session.
  *
  * @param AccessToken $token
  */
 protected function addTokenToSession(AccessToken $token)
 {
     $this->session->set('accessToken', $token->getToken());
     $this->session->set('tokenType', $token->getType());
     if ($token->getExpires()) {
         $this->session->set('expires', $token->getExpires()->getTimestamp());
     }
     if ($token->getRefreshToken()) {
         $this->session->set('refreshToken', $token->getRefreshToken()->getToken());
     }
 }