Can not run in Ubuntu

Sorry for disturbing you. When I am using Ubuntu 16.04 and Python 2.7, it shows:
`can't invoke "event" command: application has been destroyed
    while executing
"event generate $w <<ThemeChanged>>"
    (procedure "ttk::ThemeChanged" line 6)
    invoked from within
"ttk::ThemeChanged"
`
Have you ever meet with this kind of problem?
THANKS!!