Used in https://github.com/mhenc/airflow/blob/master/airflow/dag_processing/manager.py#L613

should be straighforward
The default is ``True``, but subdags will ignore this value and always
        behave as if this is set to ``False`` for backward compatibility.
        Example: A DAG is scheduled to run every midnight (``0 0 * * *``). If
        ``earliest`` is ``2021-06-03 23:00:00``, the first DagRunInfo would be
        ``2021-06-03 23:00:00`` if ``align=False``, and ``2021-06-04 00:00:00``
        if ``align=True``.
        """
        if earliest is None:
            earliest = self._time_restriction.earliest
        if earliest is None:
            raise ValueError("earliest was None and we had no value in time_restriction to fallback on")
        earliest = timezone.coerce_datetime(earliest)
        latest = timezone.coerce_datetime(latest)
        restriction = TimeRestriction(earliest, latest, catchup=True)
        
        
        
        
        
        
        if self.is_subdag:
            align = False
        try:
            info = self.timetable.next_dagrun_info(
                last_automated_data_interval=None,
                restriction=restriction,
            )
        except Exception:
            self.log.exception(
                "Failed to fetch run info after data interval %s for DAG %r",