procedure convert (
                from : in     set'class;
                to   :    out set'class)
is
        temp : set'class := from;
        elem : set_element;

begin -- convert
        
        to := empty;

        while temp /= empty
        loop
                take(
                    from    => temp,
                    element => elem);
                -- gnat bug here-not knowing how to dispatch the unit routine
                to:=union(
                    left  => to,
                    right => abstract_set_handling.unit(element => elem));
        end loop;

end convert;