I changed it in e9fa6c887f94306c1aee3f3eb90f9db05951cb97 so a track is passed to that function some times, so better reflect that in the variable name too.
MusicBrainz Picard
MusicBrainz Picard is a cross-platform (Linux/Mac OS X/Windows) application written in Python and is the official MusicBrainz tagger.
Picard supports the majority of audio file formats, is capable of using audio fingerprints (AcoustIDs), performing CD lookups and disc ID submissions, and it has excellent Unicode support. Additionally, there are several plugins available that extend Picard's features.
When tagging files, Picard uses an album-oriented approach. This approach allows it to utilize the MusicBrainz data as effectively as possible and correctly tag your music. For more information, see the illustrated quick start guide to tagging.
Picard is named after Captain Jean-Luc Picard from the TV series Star Trek: The Next Generation.
Binary downloads are available here.
Support and issue reporting
Please report all bugs and feature requests in the MusicBrainz issue tracker. If you need support in using Picard please read the documentation first and have a look at the MusicBrainz community forums.