wp post list --date_query before array

I would like to query all post before 2015. I was able to query all posts from 2015 using `wp post list --post_type=post --format=ids --date_query=2015`

How can I make this query using wp-cli?

```
'date_query' => array(
    'before' => array(
        'year' => '2015'
    ),
),
```

https://codex.wordpress.org/Class_Reference/WP_Query#Date_Parameters
