docs: def get_ids(self, start=0, rows=1000, **query_dict):
          """Retrieve a list of identifiers for documents matching the query."""
          resp_dict = self._get_query(start=start, rows=rows, **query_dict)
          return {
              'matches': resp_dict['response']['numFound'],
              'start': start,
              'ids': [d['id'] for d in resp_dict['response']['docs']],
          }