src/TimeOverlapCalculator.php
private function sortTimeSlotsByStartTime(array $timeSlots)
    {
        usort($timeSlots, function($a, $b) {
           if ($a->getStart() < $b->getStart()) {
               return -1;
           }

            if ($a->getStart() > $b->getStart()) {
                return 1;
            }

            return 0;
        });

        return $timeSlots;
    }
private function sortTimeSlotsByStartTime(array $timeSlots)
    {
        usort($timeSlots, function($a, $b) {
           if ($a->getStart() < $b->getStart()) {
               return -1;
           }

            if ($a->getStart() > $b->getStart()) {
                return 1;
            }

            return 0;
        });

        return $timeSlots;
    }
@param TimeSlotInterface[] $timeSlots

@return TimeSlotInterface[]