code: def _ParseHeader(self, parser_mediator, structure):
      
      _, month, day, hours, minutes, seconds, year = structure.date_time
  
      month = timelib.MONTH_DICT.get(month.lower(), 0)
  
      time_elements_tuple = (year, month, day, hours, minutes, seconds)
  
      try:
        date_time = dfdatetime_time_elements.TimeElements(
            time_elements_tuple=time_elements_tuple)
        date_time.is_local_time = True
      except ValueError:
        parser_mediator.ProduceExtractionWarning(
            'invalid date time value: {0!s}'.format(structure.date_time))
        return
  
      self._last_month = month
  
      event_data = XChatLogEventData()
  
      if structure.log_action[0] == 'BEGIN':
        self._xchat_year = year
        event_data.text = 'XChat start logging'
  
      elif structure.log_action[0] == 'END':
        self._xchat_year = None
        event_data.text = 'XChat end logging'
  
      else:
        logger.debug('Unknown log action: {0:s}.'.format(
            ' '.join(structure.log_action)))
        return
  
      event = time_events.DateTimeValuesEvent(
          date_time, definitions.TIME_DESCRIPTION_ADDED,
          time_zone=parser_mediator.timezone)
      parser_mediator.ProduceEventWithEventData(event, event_data)
docs: Parses a log header.
  
      Args:
        parser_mediator (ParserMediator): mediates interactions between parsers
            and other components, such as storage and dfvfs.
        structure (pyparsing.ParseResults): structure of tokens derived from
            a line of a text file.