Show a Colour Chooser dialog
        
        Usage: C{dialog.choose_colour(title="Select Colour")}
        
        @param title: window title for the dialog
        @return:
        @rtype: C{DialogData(int, Optional[ColourData])}

def choose_colour(self, title="Select Colour", **kwargs):
        """
        Show a Colour Chooser dialog
        
        Usage: C{dialog.choose_colour(title="Select Colour")}
        
        @param title: window title for the dialog
        @return:
        @rtype: C{DialogData(int, Optional[ColourData])}
        """
        return_data = self._run_zenity(title, ["--color-selection"], kwargs)
        if return_data.successful:
            converted_colour = ColourData.from_zenity_tuple_str(return_data.data)
            return DialogData(return_data.return_code, converted_colour)
        else:
            return DialogData(return_data.return_code, None)