code: def cursor_fine(self,
                      table_name,
                      start_id_obj,
                      end_id_obj,
                      iteration,
                      start_timeperiod,
                      end_timeperiod):
          
          raise NotImplementedError('method cursor_fine must be implemented by {0}'.format(self.__class__.__name__))
docs: method returns DB cursor based on precise boundaries