code: def get_items(self, source=None, target=None, crit=None):
          
          self._target_coll = target.collection
          if not crit:  # reduce any False-y crit value to None
              crit = None
          cur = source.query(criteria=crit)
          _log.info("source.collection={} crit={} source_records={:d}"
                    .format(source.collection, crit, len(cur)))
          return cur
docs: Copy records from source to target collection.
  
          :param source: Input collection
          :type source: QueryEngine
          :param target: Output collection
          :type target: QueryEngine
          :param crit: Filter criteria, e.g. "{ 'flag': True }".
          :type crit: dict