Message queues can be implemented in memory, so no network or disk I/O. In fact, it seems this project does use the built-in "queue" library: https://docs.python.org/3/library/queue.html
But, what do you think happens when you write (input) data to memory and then read (output) it from memory? I'll help you: it starts with "I" and ends with "O"!
Game over. You have no clue what you're talking about.
That's.. that's not what people mean when they talk about I/O in this context. But I think you know that, you're just grasping at straws to win an argument.