Before

Code like:

import tkinter as tk
root = tk.Tk()
print("background" in root)

Would throw a TypeError: can only concatenate str (not "int") to str

Summary of changes

• Fixed the error message when calling "option" in <tk.Misc>
• Added __contain__ method to tk.Misc since it already has __getitem__ and __setitem__
• Added tests to prevent regression

Testing

• Ran ./python -m test test_tkinter -u=gui locally to make sure the old tests as well as the new ones pass

• Issue: Tkinter misleading error in Tk.__getitem__ #140481