RadioGroup(<nTop>, <nLeft>, <nBottom>, <nRight>)
        --> <oRadioGroup>

 Arguments

     <nTop> is a numeric value that indicates the top screen row of the
     radio group.

     <nLeft> is a numeric value that indicates the left screen column of
     the radio group.

     <nBottom> is a numeric value that indicates the bottom screen row of
     the radio group.

     <nRight> is a numeric value that indicates the right screen column
     of the radio group.

 Returns

     Returns a RadioGroup object when all of the required arguments are
     present; otherwise, RadioGroup() returns NIL.