/**
* getExchangeToken - Returns an exchange token string which can be sent
* back to clients and exchanged for a device-linked access token.
*
* @param string|null $appId
* @param string|null $appSecret
*
* @return string
*/
public function getExchangeToken($appId = null, $appSecret = null)
{
return AccessToken::getCodeFromAccessToken($this->accessToken, $appId, $appSecret);
}
