code: def _process_event(self, event, tagged_data):
      
      event_type = event.WhichOneof('what')
      # Handle the most common case first.
      if event_type == 'summary':
        for value in event.summary.value:
          value = data_compat.migrate_value(value)
          tag, metadata, values = tagged_data.get(value.tag, (None, None, []))
          values.append((event.step, event.wall_time, value.tensor))
          if tag is None:
            # Store metadata only from the first event.
            tagged_data[value.tag] = sqlite_writer.TagData(
                value.tag, value.metadata, values)
      elif event_type == 'file_version':
        pass  # TODO: reject file version < 2 (at loader level)
      elif event_type == 'session_log':
        if event.session_log.status == event_pb2.SessionLog.START:
          pass  # TODO: implement purging via sqlite writer truncation method
      elif event_type in ('graph_def', 'meta_graph_def'):
        pass  # TODO: support graphs
      elif event_type == 'tagged_run_metadata':
        pass
docs: Processes a single tf.Event and records it in tagged_data.