这个闭包看不懂

protected function getClosure($abstract, $concrete)
    {
        return function ($container, $parameters = []) use ($abstract, $concrete) {
            if ($abstract == $concrete) {
                return $container->build($concrete);
            }

            return $container->resolve(
                $concrete, $parameters, $raiseEvents = false
            );
        };
    }

这个是
D:\laravel5.8\vendor\laravel\framework\src\Illuminate\Container\Container.php
第265 行，看了下不知道是什么意思