public function refreshAccessToken(OAuthToken $token)
{
$params = ['client_id' => $this->clientId, 'client_secret' => $this->clientSecret, 'grant_type' => 'refresh_token'];
$params = array_merge($token->getParams(), $params);
$request = $this->createRequest()->setMethod('POST')->setUrl($this->tokenUrl)->setData($params);
$response = $this->sendRequest($request);
$token = $this->createToken(['params' => $response]);
$this->setAccessToken($token);
return $token;
}