found_post with Timber:get_posts();

How can I get the number of post found within a get_posts query?

```
$args = array(
    'post_type' => 'news',
    'tag_id' => $search_tag->ID,
    'orderby' => 'rand'
);

$context['posts'] = Timber::get_posts($args);

//not working
$count_number = $args->found_posts;
$count_number = $context['posts']->found_posts;
```
