protected function set_slot(\scheduler_slot $slot)
 {
     $this->add_record_snapshot('scheduler_slots', $slot->data);
     $this->add_record_snapshot('scheduler', $slot->get_scheduler()->data);
     $this->slot = $slot;
     $this->data['objecttable'] = 'scheduler_slots';
 }
 public function get_value(scheduler_slot $slot, $appointment)
 {
     if (!$appointment instanceof scheduler_appointment) {
         return '';
     }
     return $this->renderer->format_grade($slot->get_scheduler(), $appointment->grade);
 }