no_one_safe

function index(){
  }
index();

public static function lastWorkingDay($day)
    {
        $date = new DateTime();
        $date->modify($day . '-1 day');
        $day = $date->format('Y-m-d');

        $weekend = static::is_weekend($day);
        if ($weekend === false) {
            return $day;
        }
        return static::lastWorkingDay($day);
    }