According to this message, Python's errno module is missing some symbols:

https://lists.ubuntu.com/archives/ubuntu-devel/2010-August/031341.html

ENOMEDIUM       123     /* No medium found */
EMEDIUMTYPE     124     /* Wrong medium type */
ECANCELED       125     /* Operation Canceled */
ENOKEY          126     /* Required key not available */
EKEYEXPIRED     127     /* Key has expired */
EKEYREVOKED     128     /* Key has been revoked */
EKEYREJECTED    129     /* Key was rejected by service */
EOWNERDEAD      130     /* Owner died */
ENOTRECOVERABLE 131     /* State not recoverable */
ERFKILL         132     /* Operation not possible due to RF-kill */

While we're at it, it might be nice to add -m functionality to print out the errno, though I'm not even sure this is possible with an extension module.