@docsubst<EOL><INDENT>@stat_1d<EOL>def _agg(self, aggregator, grid, selection=False, delay=False, progress=None):<DEDENT>
task_agg = self._get_task_agg(grid)<EOL>sub_task = aggregator.add_operations(task_agg)<EOL>return self._delay(delay, sub_task)<EOL>
:param selection: {selection}
:param delay: {delay}
:param progress: {progress}
:return: {return_stat_scalar}