Get a list of all options from OptionMenu

I want to get a list of all options from an OptionMenu widget in tkinter like so:

import tkinter

root = tkinter.Tk()

var = tkinter.StringVar(root)
var.set('OptionMenu')
optionMenu = tkinter.OptionMenu(root, var, 'foo1', 'foo2')
optionMenu.pack()

listOfAllOptions = optionMenu.getOptions()
# listOfAllOptions == ['foo1', 'foo2']

root.mainloop()

Is there a function that achieve that ? If not what is the workaround?