scp-dbus-service.py crashed with AttributeError in __getattr__(): 'gi.repository.Gtk' object has no attribute 'STOCK_CANCEL'

No idea what triggered this. Happened some time after printing and leaving stuff in the queue.

ProblemType: Crash
DistroRelease: Ubuntu 17.10
Package: system-config-printer-common 1.5.9+20170619-0ubuntu1
ProcVersionSignature: Ubuntu 4.11.0-10.15-lowlatency 4.11.8
Uname: Linux 4.11.0-10-lowlatency x86_64
ApportVersion: 2.20.6-0ubuntu4
Architecture: amd64
Date: Wed Aug 2 09:49:31 2017
ExecutablePath: /usr/share/system-config-printer/scp-dbus-service.py
InstallationDate: Installed on 2011-10-14 (2118 days ago)
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111011)
InterpreterPath: /usr/bin/python3.6
Lpstat:
 device for Canon-PIXMA-MP150: usb://Canon/MP150?serial=21BD86&interface=1
 device for HP-Officejet-Pro-276dw-MFP: dnssd://HP%20Officejet%20Pro%20276dw%20MFP%20%5BD7A6FB%5D._ipp._tcp.local/
 device for ML-4600: usb://Samsung/ML-4600
 device for Roger-Router-Fax: roger-cups:/
MachineType: LENOVO 766112G
PackageArchitecture: all
Papersize: a4
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
PpdFiles:
 Error: command ['fgrep', '-H', '*NickName', '/etc/cups/ppd/HP-Officejet-Pro-276dw-MFP.ppd', '/etc/cups/ppd/Roger-Router-Fax.ppd', '/etc/cups/ppd/ML-4600.ppd', '/etc/cups/ppd/Canon-PIXMA-MP150.ppd'] failed with exit code 2: grep: /etc/cups/ppd/HP-Officejet-Pro-276dw-MFP.ppd: Permission denied
 grep: /etc/cups/ppd/Roger-Router-Fax.ppd: Permission denied
 grep: /etc/cups/ppd/ML-4600.ppd: Permission denied
 grep: /etc/cups/ppd/Canon-PIXMA-MP150.ppd: Permission denied
ProcCmdline: /usr/bin/python3 /usr/share/system-config-printer/scp-dbus-service.py
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.11.0-10-lowlatency root=UUID=a5b30f2d-d555-4bea-9b89-e322f13656be ro quiet splash threadirqs resume=UUID=29869a91-5410-4e9b-9bd9-2aea1ecb1637 vt.handoff=7
PythonArgs: ['/usr/share/system-config-printer/scp-dbus-service.py']
SourcePackage: system-config-printer
Title: scp-dbus-service.py crashed with AttributeError in __getattr__(): 'gi.repository.Gtk' object has no attribute 'STOCK_CANCEL'
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin audio cdrom dialout fax floppy lpadmin lxd plugdev pulse-access sambashare
dmi.bios.date: 03/18/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 7LETC9WW (2.29 )
dmi.board.name: 766112G
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr7LETC9WW(2.29):bd03/18/2011:svnLENOVO:pn766112G:pvrThinkPadT61:rvnLENOVO:rn766112G:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 766112G
dmi.product.version: ThinkPad T61
dmi.sys.vendor: LENOVO