Range date (PHP)

public function create_range($start, $end, $format = 'Y-m-d') {
    $start  = new DateTime($start);
    $end    = new DateTime($end);
    $invert = $start > $end;

    $dates = array();
    $dates[] = $start->format($format);
    while ($start != $end) {
        $start->modify(($invert ? '-' : '+') . '1 day');
        $dates[] = $start->format($format);
     }
    return $dates;
}