code: def _cleanup_keys_with_confirmation(self, keys_to_delete):
      
      print('Round name: ', self.round_name)
      print('Number of entities to be deleted: ', len(keys_to_delete))
      if not keys_to_delete:
        return
      if self.verbose:
        print('Entities to delete:')
        idx = 0
        prev_key_prefix = None
        dots_printed_after_same_prefix = False
        for k in keys_to_delete:
          if idx >= 20:
            print('   ...')
            print('   ...')
            break
          key_prefix = (k.flat_path[0:1]
                        if k.flat_path[0] in [u'SubmissionType', u'WorkType']
                        else k.flat_path[0])
          if prev_key_prefix == key_prefix:
            if not dots_printed_after_same_prefix:
              print('   ...')
            dots_printed_after_same_prefix = True
          else:
            print('  ', k)
            dots_printed_after_same_prefix = False
            idx += 1
          prev_key_prefix = key_prefix
      print()
      inp = input_str('Are you sure? (type "yes" without quotes to confirm): ')
      if inp != 'yes':
        return
      with self.datastore_client.no_transact_batch() as batch:
        for k in keys_to_delete:
          batch.delete(k)
      print('Data deleted')
docs: Asks confirmation and then deletes entries with keys.
  
      Args:
        keys_to_delete: list of datastore keys for which entries should be deleted