code: def process_default(self, event):
          
          self._stats_lock.acquire()
          try:
              events = event.maskname.split('|')
              for event_name in events:
                  count = self._stats.get(event_name, 0)
                  self._stats[event_name] = count + 1
          finally:
              self._stats_lock.release()
docs: Processes |event|.