vButton with MCP23017

Hello,
I wanted to try the vButton function on a button connected to an MCP23017 I/O Expander and. The MCP23017 is connected to an atmega328p. Unfortunately, no matter what I try, I can't get the code running. And I can't find any example code for it either.
For the MCP23017 I used the Adafruit_MCP23X17.h library!

Has anyone done this before and can help me?

Thanks!