public function login($credentials)
{
$user = $credentials['user'];
$password = $credentials['password'];
$this->_client = new \Oara\Curl\Access($credentials);
$valuesLogin = array(new \Oara\Curl\Parameter('username', $user), new \Oara\Curl\Parameter('password', $password));
$loginUrl = "{$this->_extension}/login.html";
$urls = array();
$urls[] = new \Oara\Curl\Request($loginUrl, $valuesLogin);
$this->_client->post($urls);
}