def makeDateStamp(instant):
    """
    Serialize a L{datetime.datetime} according to the AWS "date stamp"
    format.

    @param instant: A naive UTC L{datetime.datetime} (as returned from
        L{datetime.datetime.utcnow})
    @type instant: L{datetime.datetime}

    @return: The formatted date and time.
    @rtype: L{str} (native string).
    """
    return instant.strftime('%Y%m%d')
