ok, i had to install ttk from https://pypi.python.org/pypi/pyttk
If you still want to do it depending only on the standard library:
>>> import tkinter as tk>>> root = tk.Tk()>>> print(root.tk.call('ttk::themes'))('classic', 'default', 'clam', 'winnative', 'vista', 'xpnative', 'alt')