private function _getOAuth()
{
$oauth = new OAuth($this->key, $this->secret, OAUTH_SIG_METHOD_HMACSHA1, OAUTH_AUTH_TYPE_FORM);
if (isset($_SESSION['access_key']) && isset($_SESSION['access_secret'])) {
$oauth->setToken($_SESSION['access_key'], $_SESSION['access_secret']);
} else {
if (isset($_SESSION['request_key']) && isset($_SESSION['request_secret'])) {
$oauth->setToken($_SESSION['request_key'], $_SESSION['request_secret']);
}
}
return $oauth;
}