Python one line if-else with different operators

I was fiddling with one line if and for statements in python and ran across the following problem:

I can make something like the following work:

state = 1 if state == 4 else 2

But I want to use = and += in the same context, something like this:

state = 1 if state == 4 else state+=1

How can I implement this in one line?