def _link_arrows( self, do_binding ) :
        """Internal routine to set links for menu traversal"""

        # we won't bother if there's only one item in the menu
        if len( self._selectables ) < 1 :
            return

        for i in range( len( self._selectables ) ) :
            w = self._selectables[ i ]
            wtype =  w.wdict[ 'type' ]
            # skip over widgets with the arrow keys
            if wtype != 'widget' :
                w.wnext = self._selectables[ ( i + 1 ) %
                                            len( self._selectables ) ]
                w.wprev = self._selectables[ i - 1 ]
                if do_binding :
                    self._bind_traversal( w )
Internal routine to set links for menu traversal
recipes/Python/442500_ExtraMenu__TkInter_menu_arbitrary_widgets/recipe-442500.py