lled packages.

        The version number and target release of the packages can be specified
        using the traditional apt-get syntax, e.g. "xterm=281.1" to force
        installing the version 281.1 of xterm or "xterm/experimental" to
        force installing xterm from the experimental release.

        :param package_names: The list of package which should be upgraded.

        :param wait: if True run the transaction immediately and return its
            exit state instead of the transaction itself.
        :param reply_handler: Callback function. If specified in combination
            with error_handler the method will be called asynchrounsouly.
        :param error_handler: Errback function. In case of an error the given
            callback gets the corresponding exception instance.
        :param defer: Run the method asynchrounsly and return a defer.Deferred.
            This options is only available as a keyword.

        :raises: dbus.DBusException

        :returns: An AptTransaction instance.
        ZUpgradePackagesr§