如何使用通过composer安装的库中的类？

I instaled wpdesk/wp-basic-requirements

using

composer require wpdesk/wp-basic-requirements

but have no idea how to use. I tried

use WPDesk_Requirement_Checker;

in my php class but Wordpress returned Warning:

The use statement with non-compound name 'WPDesk_Requirement_Checker' has no effect in /var/www/html/wcexport/wp-content/plugins/export-`csv/libs/TKExportConfig.php on line 6

How to use properny methods like

WPDesk_Basic_Requirement_Checker::is_php_at_least('7.3');

In composer.json:

{
    "require": {
        "league/csv": "^9.3",
        "wpdesk/wp-basic-requirements": "^2.4"
    }
}