The sunny-day action is to echo the counterpart to stdout.

    :param string: The lookup string  (UNUSED)
    :param counterpart: The counterpart that the string mapped to
    :param options: ArgumentParser or equivalent to provide options.no_newline
    :param rc_so_far: Stays whatever value it was.

def counterpart_found(string, counterpart, options, rc_so_far):
    """The sunny-day action is to echo the counterpart to stdout.

    :param string: The lookup string  (UNUSED)
    :param counterpart: The counterpart that the string mapped to
    :param options: ArgumentParser or equivalent to provide options.no_newline
    :param rc_so_far: Stays whatever value it was.
    """
    format = "%s" if options.no_newline else "%s\n"
    sys.stdout.write(format % (counterpart))
    return rc_so_far or 0