Suggestion: Order by is null condition

I am using CI 4.2.1 on my project

I needed to use ORDER BY IS NULL ASC/DESC on a datetime from my db.
How about to add the possibility to add a conditional order by is null?

CodeIgniter\Database\BaseBuilder (line 1422)
Previously
$direction = in_array($direction, ['ASC', 'DESC'], true) ? ' ' . $direction : '';


In
$direction = in_array($direction, ['ASC', 'DESC', 'IS NULL ASC', 'IS NULL DESC'], true) ? ' ' . $direction : '';