'clear and reload the menu with a new set of options.
valueList - list of new options
value - initial value to set the optionmenu\'s menubutton to'

def SetMenu(self, valueList, value=None):

    self['menu'].delete(0, 'end')
    for item in valueList:
        self['menu'].add_command(label=item, command=_setit(self.variable, item, self.command))
    if value:
        self.variable.set(value)
