src/ServiceProvider.php
protected static function instantiateServiceContainer()
    {
        $container = Container::getInstance();

        if (!$container) {
            $container = new Container();
            Container::setInstance($container);
        }

        return $container;
    }
protected static function instantiateServiceContainer()
    {
        $container = Container::getInstance();

        if (!$container) {
            $container = new Container();
            Container::setInstance($container);
        }

        return $container;
    }
Instantiate service container if it's not instantiated yet.