whmcsProxmoxAddon/core/App/Controllers/AppControllers/Api.php

<?php

namespace ModulesGarden\ProxmoxAddon\Core\App\Controllers\AppControllers;

use ModulesGarden\ProxmoxAddon\Core\App\Controllers\Interfaces\AppController;

class Api implements AppController
{

    public function getControllerInstanceClass($callerName, $params)
    {
        // TODO: Implement getControllerInstanceClass() method.
    }
}