code: def _set_rowcount(self, query_results):
          
          total_rows = 0
          num_dml_affected_rows = query_results.num_dml_affected_rows
  
          if query_results.total_rows is not None and query_results.total_rows > 0:
              total_rows = query_results.total_rows
          if num_dml_affected_rows is not None and num_dml_affected_rows > 0:
              total_rows = num_dml_affected_rows
          self.rowcount = total_rows
docs: Set the rowcount from query results.
  
          Normally, this sets rowcount to the number of rows returned by the
          query, but if it was a DML statement, it sets rowcount to the number
          of modified rows.
  
          :type query_results:
              :class:`~google.cloud.bigquery.query._QueryResults`
          :param query_results: results of a query