Laravel / Eloquent WHERE NOT SUBQUERY

I`m having trouble to setup a negative condition like such:

WHERE NOT( "last_day" "<=" $first_day OR "first_day" "<=" $last_day)

My query builder looks like this atm:

$query = $query->where(function ($query) use ($first_day, $last_day) {
   $query->where('last_day', '<=', $first_day);
   $query->orWhere('first_day', '<=', $last_day);
});

I would like it to be as such : $query->whereNot(function (.....

How can I accomplish this?

source : http://ift.tt/2nAYBjd

via Chebli Mohamed