public function showUserVisitors($user_id, $limit = 1, $offset = 0)
    {
        if (!is_numeric($user_id) || 0 >= $user_id) {
            throw new InvalidArgumentException(
                "Api::showUserVisitors user_id field should be positive integer", 404);
        }


        if ($limit < 1) {
            throw new InvalidArgumentException(
                "Api::showUserVisitors() limit must be a min 1 ");
        }
        if ($offset < 0) {
            throw new InvalidArgumentException(
                "Api::showUserVisitors() $offset must be a positive number,  min 0 ");
        }

        $command = $this->client->getCommand(
            'ShowUserVisitors',
            array('id'=>$user_id, 'limit'=>$limit,'offset'=>$offset)
        );
        return $this->executeCommand($command);
    }