Using Google api in CodeIgniter 4

Question

I want to use google api in my CodeIgniter 4.

First I have downloaded and installed google api from https://github.com/googleapis/google-api-php-client

2nd i need to create library in CI4 library

require APPPATH . "ThirdParty/google/vendor/autoload.php";

class Google extends Google_Client {
    function __construct($params = array()) {
        parent::__construct();
}

}

Then i want to access in my model model constructor code is below

public function __construct()
{
    parent::__construct();
    $this->load->library('google');
}

after loading library is showing error

Error Call to a member function library() on null

please help how should i use