def start_of_local_day(dt_or_d: dt.date | dt.datetime | None = None) -> dt.datetime:
"""Return local datetime object of start of day from date or datetime."""
if dt_or_d is None:
date: dt.date = now().date()
elif isinstance(dt_or_d, dt.datetime):
date = dt_or_d.date()
else:
date = dt_or_d
return dt.datetime.combine(date, dt.time(), tzinfo=DEFAULT_TIME_ZONE)
