how to get post order by post id wp_query?

I have 4 posts and I displaying 2 posts per page.

$ids = array('16085','16088','16083','16091');

$options = array(
        'post_type' => $post_type,
        'posts_per_page' => $posts_per_page,
        'paged'     => $paged,
        'meta_query' => $meta_query,
        'tax_query' => $tax_query,
        'post__in ' => $ids,
        'orderby' => 'post__in',
);
$get_properties = new WP_Query( $options ); 

I want to display posts in a specific order is given $ids array.