Question about '|' what it does exactly?

Question

First than anything... Sorry for my poor english.
In an exercise fron here, i have:
A=0
If a|0:
Something x
Else:
Something y
(A|0) what it does??

Answer 1

This is a good overview:
https://www.sololearn.com/learn/4070/?ref=app

Answer 2

Good answer, thanks