code: def print_event_count():
      
      for source in archive.list_event_sources():
          event_count = 0
          for group in archive.list_event_histogram(source):
              for rec in group.records:
                  event_count += rec.count
          print('  {: <40} {: >20}'.format(source, event_count))
docs: Print the number of events grouped by source.