Add external buttons for flippers in Pinball game

How would external buttons be added to the Pinball Game with a Pico W driving a Waveshare round1.28" display (GC9A01 driver?)  My button code works on the GPIO's of the Pico W but I am at a loss of how to pass the button states into pinball.py or tft_buttons.py.
Thanks all!
Charles 