How do I update a variable/function?

Question

Python

I'm writing a program that, when a button is clicked, activates a function that takes text from the clipboard, modifies that text in some way, and pastes it back into the clipboard.
How can I make it so that the variable that stores this text is updated either after a certain period of time, or when the clipboard data changes (preferably), or even somehow works automatically.
I searched on google, didn't find it.

Answer 1

Googled badly :)
Tyk
And about the check, the dumbest solution not to think is to create a function in which there will be a variable from the old information and in the While True loop every second we will receive data from the buffer and if'om check whether they are the same