code: def ExamineEvent(self, mediator, event):
      
      self._EnsureRequesterStarted()
  
      path_spec = event.pathspec
      event_identifiers = self._event_identifiers_by_pathspec[path_spec]
  
      event_identifier = event.GetIdentifier()
      event_identifiers.append(event_identifier)
  
      if event.data_type not in self.DATA_TYPES or not self._analyzer.lookup_hash:
        return
  
      lookup_hash = '{0:s}_hash'.format(self._analyzer.lookup_hash)
      lookup_hash = getattr(event, lookup_hash, None)
      if not lookup_hash:
        display_name = mediator.GetDisplayNameForPathSpec(path_spec)
        logger.warning((
            'Lookup hash attribute: {0:s}_hash missing from event that '
            'originated from: {1:s}.').format(
                self._analyzer.lookup_hash, display_name))
        return
  
      path_specs = self._hash_pathspecs[lookup_hash]
      path_specs.append(path_spec)
      # There may be multiple path specification that have the same hash. We only
      # want to look them up once.
      if len(path_specs) == 1:
        self.hash_queue.put(lookup_hash)
docs: Evaluates whether an event contains the right data for a hash lookup.
  
      Args:
        mediator (AnalysisMediator): mediates interactions between
            analysis plugins and other components, such as storage and dfvfs.
        event (EventObject): event.