def parse(representation):
    """Attempts to parse an ISO8601 formatted ``representation`` string,
    which could be of any valid ISO8601 format (date, time, duration, interval).

    Return value is specific to ``representation``.
    """
    representation = str(representation).upper().strip()

    if '/' in representation:
        return parse_interval(representation)

    if representation[0] is 'P':
        return parse_duration(representation)

    return parse_date(representation)