docs: def _join_date_and_time(dates, times, joiner):
    """Returns a tuple of all date and time format strings joined together by
    :joiner:.
  
    :dates: an enumerable of date format strings
    :times: an enumerable of time format strings
    :joiner: a string to join a date and time format together
    """
    return tuple("{}{}{}".format(d, joiner, t) for (d, t) in itertools.product(dates, times))