class PackageManagerRequirements

class PackageManagerRequirements implements InstallRequirementsInterface {
    
    /**
     * {@inheritdoc}
     */
    public static function getRequirements() : array {
        $requirements = [];
        if (Settings::get('testing_package_manager', FALSE) === FALSE) {
            $requirements['testing_package_manager'] = [
                'title' => 'Package Manager',
                'description' => t("Package Manager is available for early testing. To install the module set the value of 'testing_package_manager' to TRUE in your settings.php file."),
                'severity' => REQUIREMENT_ERROR,
            ];
        }
        // If we're able to check for the presence of the failure marker at all, do
        // it irrespective of the current run phase. If the failure marker is there,
        // the site is in an indeterminate state and should be restored from backup
        // ASAP.
        $service_id = FailureMarker::class;
        if (\Drupal::hasService($service_id)) {
            try {
                \Drupal::service($service_id)->assertNotExists(NULL);
            } catch (FailureMarkerExistsException $exception) {
                $requirements['package_manager_failure_marker'] = [
                    'title' => t('Failed Package Manager update detected'),
                    'description' => $exception->getMessage(),
                    'severity' => REQUIREMENT_ERROR,
                ];
            }
        }
        return $requirements;
    }

}