Back button not working in my py

[Handy77]

I have to create a file for my assignment . Problem is I have got most of it to work. Only problem I want back buttons to go back to the home page for the customer. Customer is like menu options choice where you want to go like make a booking. If I want to go back to the customer home page gives errors.

Any way to send private message someone can check it for me.

I have from order import ui_order, from booking import ui_booking in my customer.py. Def ordershow, def bookingshow So I can go to those pages. I have now added from customer import ui_customer in order, booking.py so back button will take me back to customer page. But it is giving me errors ui_customer

Any help appreciated

Python 3.40