ll receive
        the object-path of the sending object as a keyword argument
        with this name.
    `message_keyword` : str
        If not None (the default), the handler function will receive
        the `dbus.lowlevel.SignalMessage` as a keyword argument with
        this name.
    `arg...` : unicode or UTF-8 str
        If there are additional keyword parameters of the form
        ``arg``\ *n*, match only signals where the *n*\ th argument
        is the value given for that keyword parameter. As of this
        time only string arguments can be matched (in particular,
        object paths and signatures can't).
    `arg0namespace` : str
        If not None (the default) match only signals where the first
        argument is a string that either is equal to the
        keyword parameter, or starts with the keyword parameter
        followed by a dot (and optionally more text).
    `arg...path`: str
        If there are additional keyword parameters of the form
        ``arg``\ *n* ``path``, match only signals where the *n*\ th
        argument is either equal or matches in a path like manner.
        A path-like comparison matches when either the keyword or the
        argument ends with a '/' and is a prefix of the other. An
        example argument path match is arg0path='/aa/bb/'. This would
        match messages with first arguments of '/', '/aa/', '/aa/bb/',
        '/aa/bb/cc/' and '/aa/bb/cc'. It would not match messages with
        first arguments of '/aa/b', '/aa' or even '/aa/bb'.
    `named_service` : str
        A deprecated alias for `bus_name`.
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