[Tutor] What is the augmented assignment operator "^="

[Dick Moores]

The docs list it at <http://docs.python.org/ref/augassign.html>, and 
send you to <http://docs.python.org/ref/primaries.html#primaries>, 
which seems a dead end.

I've tried "^=" out a bit:

 >>> n = 5
 >>> n ^= 8
 >>> n
13
 >>> n ^= 8
 >>> n
5
 >>> n ^= 8
 >>> n
13
 >>> n ^= 8
 >>> n
5

and get that strange alternating behavior. Can someone explain?  And 
while at it, please also explain "&=" and "|=".

Thanks,

Dick Moores