public function getAccessTokenData()
    {
        if ($this->isOauth1()) {
            return array(
                'access_token'        => $this->_access_token,
                'access_token_secret' => $this->_access_token_secret,
                'expires'             => $this->_expires,
            );
        }

        return array(
            'access_token'  => $this->_access_token,
            'expires'       => $this->_expires,
            'token_type'    => $this->_token_type,
            'refresh_token' => $this->_refresh_token
        );
    }