code: def init_from_datastore(self):
      
      self._attacks = {}
      self._targeted_attacks = {}
      self._defenses = {}
      for entity in self._datastore_client.query_fetch(kind=KIND_SUBMISSION):
        submission_id = entity.key.flat_path[-1]
        submission_path = entity['submission_path']
        participant_id = {k: entity[k]
                          for k in ['team_id', 'baseline_id']
                          if k in entity}
        submission_descr = SubmissionDescriptor(path=submission_path,
                                                participant_id=participant_id)
        if list(entity.key.flat_path[0:2]) == ATTACKS_ENTITY_KEY:
          self._attacks[submission_id] = submission_descr
        elif list(entity.key.flat_path[0:2]) == TARGET_ATTACKS_ENTITY_KEY:
          self._targeted_attacks[submission_id] = submission_descr
        elif list(entity.key.flat_path[0:2]) == DEFENSES_ENTITY_KEY:
          self._defenses[submission_id] = submission_descr
docs: Init list of submission from Datastore.
  
      Should be called by each worker during initialization.