php check if given date time string has passed, tomorrow, today or other time

function check_date_time_string($date_time_string) {
  $now = new DateTime();
  $date_time = new DateTime($date_time_string);
  
  if($now > $date_time) {
    return "passed";
  }else if($date_time > $now->modify('+1 day')) {
    return "tomorrow";
  }else if($date_time > $now->modify('-1 day')) {
    return "today";
  }else {
    return "other";
  }
}