is this a Python bug?

[Brian Langenberger]

piet at cs.uu.nl wrote:
:>>>>> Moshe Zadka <moshez at math.huji.ac.il> (MZ) writes:

: MZ> On 15 Feb 2000, Brian Langenberger wrote:
:>> R is supposed to work to give raw strings with the backslashes stored
:>> as backslashes.  I've never had a problem until I tried making a
:>> string with nothing but backslashes.  

: MZ> Raw strings cannot end with a backslash. 

: They can. But only with an even number of them.

I'm assuming there's some clever and important reason for this.
But for the life of me I can't figure out what it is.
Could someone enlighten me as to the reason? :)