package python3 3.4.3-4ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 4

[Espen]

Happened while casually upgrading to 15.10 (Was sticking to LTS for a while.)

ProblemType: Package
DistroRelease: Ubuntu 15.10
Package: python3 3.4.3-4ubuntu1
ProcVersionSignature: Ubuntu 4.2.0-22.27-generic 4.2.6
Uname: Linux 4.2.0-22-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
Date: Mon Jan 4 11:18:18 2016
DuplicateSignature: package:python3:3.4.3-4ubuntu1:subprocess installed post-installation script returned error exit status 4
ErrorMessage: subprocess installed post-installation script returned error exit status 4
InstallationDate: Installed on 2013-11-16 (778 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
RelatedPackageVersions:
 dpkg 1.18.2ubuntu5.1
 apt 1.0.10.2ubuntu1
SourcePackage: python3-defaults
Title: package python3 3.4.3-4ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 4
UpgradeStatus: Upgraded to wily on 2016-01-04 (0 days ago)