AttributeError: 'NoneType' object has no attribute 'origins'

[blackknight36]

Packages with a missing origin cause the pkg-exporter script to crash with an error as follows.

Traceback (most recent call last):
File "/usr/local/bin/pkg-exporter", line 8, in
sys.exit(main())
File "/usr/local/lib/python3.8/dist-packages/pkg_exporter/textfile.py", line 39, in main
pkgmanager.query()
File "/usr/local/lib/python3.8/dist-packages/pkg_exporter/pkgmanager/apt.py", line 63, in query
for origin in selected_package.candidate.origins:
AttributeError: 'NoneType' object has no attribute 'origins'