def destinations(mlist):
    """Generate just the local parts for the mailing list aliases.

        This method is a generator.  The posting address will be returned
        first, followed by the rest of the aliases in alphabetical order.

        :param mlist: The mailing list.
        :type mlist: An `IMailingList` or an object with a `list_name`
            attribute.
        :return: The set of short (i.e. without the @dom.ain part) common
            aliases for the mailing list.
        :rtype: string
        """
