Modify weekdays php 5.3

Recently I needed to add a certain amount of weekdays onto a date using php 5.3.

I wrote this simple function which has two parameters, the amount of weekdays I want to add and the date I want to add them to as an instance of DateTime as follows:

/**
* @param int $weekDays
* @param DateTime $date
* @return DateTime
*/
public function addWeekdaysToDateTime($weekDays, DateTime $date)
{
    $days = 0;

    //only increase the day count for weekdays
    while ($days < $weekDays) {
        $date->modify("+1 day");

        //if we're now on a weekday, increase the weekday counter
        if (!in_array($date->format("D"), ['Sat', 'Sun'])) {
            $days++;
        }
    }
    return $date;
}