docs: def to_datetime(plain_date, hours=0, minutes=0, seconds=0, ms=0):
      """given a datetime.date, gives back a datetime.datetime"""
      # don't mess with datetimes
      if isinstance(plain_date, datetime.datetime):
          return plain_date
      return datetime.datetime(
          plain_date.year,
          plain_date.month,
          plain_date.day,
          hours,
          minutes,
          seconds,
          ms,
      )