code: public void deleteTrigger(String triggerGroup, Trigger trigger) throws SchedulerException {
          triggerDao.deleteTrigger(triggerGroup, trigger);
          if (trigger instanceof ScheduledTrigger) {
              unscheduleTrigger((ScheduledTrigger) trigger);
          }
      }
docs: Deletes/Removes the {@code Trigger}. If it is a {@code ScheduledTrigger} then it is also un-scheduled from
  scheduler.
  @warn exception SchedulerException description missing
  
  @param trigger the {@code Trigger} to be removed