a = a ^ b
b = a ^ b
a = a ^ b

So you are asking the user to do it

Version 3 is disgusting.

Storing the value in the user instead of RAM!

Using an organic processor

I raise you

@lambda _: _()
def result() -> int:
    global a; global b; a, b = b, a

hat tip to @sisyphean@programming.dev via Cursed Python