def birthdays_subcommand(vcard_list, parsable):
    """Print birthday contact table.

    :param vcard_list: the vcards to search for matching entries which should
        be printed
    :type vcard_list: list of carddav_object.CarddavObject
    :param parsable: machine readable output: columns devided by tabulator (\t)
    :type parsable: bool
    :returns: None
    :rtype: None

    """
    # filter out contacts without a birthday date
    vcard_list = [
        vcard for vcard in vcard_list if vcard.get_birthday() is not None]
    # sort by date (month and day)
    # The sort function should work for strings and datetime objects.  All
    # strings will besorted before any datetime objects.
    vcard_list.sort(
        key=lambda x: (x.get_birthday().month, x.get_birthday().day)
        if isinstance(x.get_birthday(), datetime.datetime)
        else (0, 0, x.get_birthday()))
    # add to string list
    birthday_list = []
    for vcard in vcard_list:
        date = vcard.get_birthday()
        if parsable:
            if config.display_by_name() == "first_name":
                birthday_list.append("%04d.%02d.%02d\t%s"
                                     % (date.year, date.month, date.day,
                                        vcard.get_first_name_last_name()))
            else:
                birthday_list.append("%04d.%02d.%02d\t%s"
                                     % (date.year, date.month, date.day,
                                        vcard.get_last_name_first_name()))
        else:
            if config.display_by_name() == "first_name":
                birthday_list.append("%s\t%s"
                                     % (vcard.get_first_name_last_name(),
                                        vcard.get_formatted_birthday()))
            else:
                birthday_list.append("%s\t%s"
                                     % (vcard.get_last_name_first_name(),
                                        vcard.get_formatted_birthday()))
    if birthday_list:
        if parsable:
            print('\n'.join(birthday_list))
        else:
            list_birthdays(birthday_list)
    else:
        if not parsable:
            print("Found no birthdays")
        sys.exit(1)
Print birthday contact table.

    :param vcard_list: the vcards to search for matching entries which should
        be printed
    :type vcard_list: list of carddav_object.CarddavObject
    :param parsable: machine readable output: columns devided by tabulator (\t)
    :type parsable: bool
    :returns: None
    :rtype: None