PYTHON- tkinter ERROR Cant evoke event command -

i making simple program incorporates use of tkinter. inclusion have copy , paste clipboard , check contents of keyboard. however, without change me, console spits out error :

can't invoke "event" command: application has been destroyed while executing  "event generate $w <<themechanged>>" (procedure "ttk::themechanged" line 6) invoke within "ttk::themechanged"`  

my questions:

1. i not understand error means;
2. i not understand how fix it.

from understanding, these error pop use of matplotlib, not using. python console still can function after message annoying , distracting.

here code think affecting it.

from tkinter import tk  r = tk()  r.withdraw()  r.clipboard_clear()  r.clipboard_append(finalbib)  r.destroy() #os.startfile("temppy.py") clipbardtest=true while clipbardtest:     r=tk()     clippytest = r.clipboard_get()     r.destroy()     if clippytest==finalbib:         os.system('cls')         print "successfully copied clipboard"         #os.remove("temppy.py")         clipbardtest=false         morebibdef()             else:         time.sleep(1.2)         #os.startfile("temppy.py")         r = tk()          r.withdraw()          r.clipboard_clear()          r.clipboard_append(finalbib)          r.destroy() 

see 1 of comments this question

if use in console script might lead error, .destroy() function not work ("can't invoke "event" command: application has been destroyed while executing [...]"). prevent this, call r.update() before r.destroy.