[Python-Dev] Omission in re.sub?

[MRAB]

I've just come across an omission in re.sub which I hadn't noticed
before.

In re.sub the replacement string can contain escape sequences, for
example:

 >>> repr(re.sub(r"x", r"\n", "axb"))
"'a\\nb'"

However:

 >>> repr(re.sub(r"x", r"\x0A", "axb"))
"'a\\\\x0Ab'"

Yes, it doesn't recognise "\xNN".

Is there a reason for this?

The regex module does the same, but is there any objection to me fixing
it in the regex module? (I'm thinking about compatibility with re here.)