Issue #20567: Delete class attribute gui widgets in idle tests.
Code patch by Serhiy Storchaka
diff --git a/Lib/test/test_idle.py b/Lib/test/test_idle.py
index 07f45c6..495b416 100644
--- a/Lib/test/test_idle.py
+++ b/Lib/test/test_idle.py
@@ -14,6 +14,7 @@
     try:
         root = tk.Tk()
         root.destroy()
+        del root
     except tk.TclError:
         while 'gui' in use_resources:
             use_resources.remove('gui')