function test_init()
{
    $sandbox = new PHPSandbox\PHPSandbox();
    $sandbox->whitelist_func('test');
    try {
        $result = $sandbox->execute(function () {
            return test('world');
        });
    } catch (Exception $e) {
        $result = $e;
    }
    var_dump($result);
    //Hello world
}