code: def PopEvent(self):
      
      try:
        macb_group_identifier, content_identifier, event = heapq.heappop(
            self._heap)
        if macb_group_identifier == '':
          macb_group_identifier = None
        return macb_group_identifier, content_identifier, event
  
      except IndexError:
        return None
docs: Pops an event from the heap.
  
      Returns:
        tuple: containing:
  
          str: identifier of the event MACB group or None if the event cannot
              be grouped.
          str: identifier of the event content.
          EventObject: event.