public static function get_token_linuxdo($arg,$type,$code){

        $arg['code'] = $code;
        $arg['grant_type'] = 'authorization_code';
        $arg['redirect_uri'] = B2_HOME_URI.'/open?type='.$type;

        $res = wp_remote_post($arg['url'], 
            array(
                'method' => 'POST',
                'body' => $arg,
            )
        );

        if(is_wp_error($res)){
    ...