Cannot generate recipe from tutorial (appimage-builder)

I’m following the tutorial at
https://appimage-builder.readthedocs.io/en/latest/intro/tutorial.html

I reached the step of running appimage-builder --generate
fill in everything as default
the test application runs
I exercise it and close it
there is a lengthy error message ending with

  File "/usr/local/lib/python3.7/dist-packages/appimagebuilder/gateways/dpkg_query.py", line 63, in depends
    raise DpkgQueryError("Package lockup failed")
appimagebuilder.gateways.dpkg_query.DpkgQueryError: Package lockup failed

The result is that AppImageBuilder.yml is not created.

I am not running any package manager tools at the same time.
I can post the whole message if you like. This is running on Debian Buster.

Thanks in advance

(Edited to try to improve formatting)

Hi @mukoan. I am not sure whether the author of appimage-builder is reading here, so please ask over at Issues · AppImageCrafters/appimage-builder · GitHub. Thanks!