[php] usort

$now = new DateTime();
$month = clone $now;
$twoweek = clone $now;
$month->modify('+1 month');
$twoweek->modify('+2 weeks');

$dates = array(
  $twoweek,
  $month,
  $now
);

usort($dates, function(DateTime $a, DateTime $b){
            if($a == $b){
                return 0;
            }

            return $a > $b ? 1 : -1;
        });