<oRadioGroup>:select(<nPosition>) --> self

        <nPosition> is a numeric value that indicates the position in the
        list of the radio button to be selected.

        select() is a method of the RadioGroup class that is used for
        changing the selected radio button in a radio group.  Its state is
        typically changed when one of the arrow keys is pressed or the
        mouse's left button is pressed when its cursor is within one of the
        radio button's screen region.

        This message is meaningful only when the RadioGroup object has input
        focus.