utf-8 problems - python 2.7 and Tkinter

primer.xml

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<elements>
    <element>
        <SA008>ččžžšš</SA008>
        <DI001>Ime</DI001>
        <PE019>ocena SLO</PE019>
        <PE020>ocena 2</PE020>
        <LS003>uspeh</LS003>
    </element>

</elements>

vprasaj.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from Tkinter import *

def main():
    window = Tk()
    name_l = Label(window, text=" Ime: ")
    name_l.grid(row=2, column=0)
    name = Entry(window)
    name.grid(row=2, column=1)

    # seznam uspehov na spričevalu
    uspeh_list = ["izberi", "odličen"]

    selected_uspeh = StringVar()
    selected_uspeh.set(uspeh_list[0])

    uspeh = Label(window, text=" Uspeh: ")
    uspeh.grid(row=5, column=0, sticky=E)
    uspeh_menu = OptionMenu(window, selected_uspeh, *uspeh_list)
    uspeh_menu.grid(row=5, column=1)

    # tu še funkcija za pridobivanje podatkov

    def get_data():

        name_dijak = name.get()
        uspeh_dijak = selected_uspeh.get()
        podatki_o_spricevalu = {"name": name_dijak, "uspeh":uspeh_dijak}

        print podatki_o_spricevalu
        return podatki_o_spricevalu


    def make_xml():

        podatki = get_data()
        print ("Tole so podatki v obliki dictionary:")
        print podatki
        # odpremo pravo xml datoteko
        import xml.etree.ElementTree as ET

        with open('primer.xml','r') as tree_file:
            tree = ET.parse(tree_file)
        root = tree.getroot()

        name = root[0][1].text
        root[0][1].text = podatki["name"]

        uspeh = root[0][4].text
        root[0][4].text = podatki["uspeh"]
        tree.write('primer_out.xml')

        print root[0][1].text




    # gumb naredi xml
    Label(window, text="Make xml:", ).grid(row=20, column=0, sticky=E)
    Button(window, text="XML ", width=14, command=make_xml).grid(
        row=20, column=1, sticky=E)


    window.mainloop()


if __name__ == "__main__":
    main()