code: def _merge_search_result(self, search_results, _or=False):
          
          all_docids = reduce(add, [list(x.keys()) for x in search_results])
          if _or:
              return sorted(set(all_docids), key=all_docids.index)
          return [docid for docid in set(all_docids) if all_docids.count(docid) > 1]
docs: Merge of filter search results
          Params:
              <str> | <Sequential> query
              <bool> _or
          Return:
              <list> computed_dids