ionGroup does not exactly map the optparse.OptionGroup
        interface. There is no parser object to supply, but it is possible
        to set default values and option_lists. Also the default values and
        values are not shared with the OptionParser.

    To pass a OptionGroup into a function which expects a GOptionGroup (e.g.
    gnome_program_init() ). OptionGroup.get_option_group() can be used.

    For further help, see optparse.OptionGroup.
    