我創建了一個菜單，可以在其中顯示用戶輸入的變量。如果用戶什么都不輸入，則默認設置。問題是我在執行模塊時收到錯誤。默認設置的變量：tab = "True" 和 amount = "N/A"代碼：def menu(): print(""" * = Optional    1. Start the application.     2. Set crate.    3. Set link for crate. *    4. Settings. *""")menu_qsone = str(input("> "))if menu_qsone == "4":    clear()    settings()def settings():    print("Settings: ")    print("1. Open a tab when the program is launched." + (tab))    print("2. Times the script will be used." + (amount))    print("3. Return to menu.")    qs_one = str(input("> "))    if qs_one == "1":        clear()        if tab == "True":            tab = "False"            clear()            settings()        if tab == "False":            tab = "True"            clear()            settings()    if qs_one == "2":        clear()        print("How many times would you like to run the script?")        qs_two = str(input("> "))        amount = (qs_two)        clear()        settings()    if qs_one == "3":        clear()        menu()menu()錯誤;Traceback (most recent call last):  File "C:\Users\Stagiair\Desktop\PauzeProject\MainFile.py", line 63, in <module>    menu()  File "C:\Users\Stagiair\Desktop\PauzeProject\MainFile.py", line 32, in menu    settings()  File "C:\Users\Stagiair\Desktop\PauzeProject\MainFile.py", line 36, in settings    print("1. Open a tab when the program is launched." + (tab))UnboundLocalError: local variable 'tab' referenced before assignment