code: def get_next_batch(self):
          
          if self.collection_scanner.is_enabled:
              batch = self.collection_scanner.get_new_batch()
              for item in batch:
                  base_item = BaseRecord(item)
                  self.increase_read()
                  self.last_position['last_key'] = item['_key']
                  yield base_item
              self.logger.debug('Done reading batch')
          else:
              self.logger.debug('No more batches')
              self.finished = True
docs: This method is called from the manager. It must return a list or a generator
          of BaseRecord objects.
          When it has nothing else to read, it must set class variable "finished" to True.