nattka should not crash, if -a is missing

[jonasstein]

https://wiki.gentoo.org/wiki/Nattka suggests

Package list for stablereq
user $nattka make-package-list -s 'dev-java/log4j-12-api-2.18.0'

So I tried
nattka make-package-list -s 'dev-util/reuse-2.1.0' which crashes with

$ nattka make-package-list -s 'dev-util/reuse-2.1.0'
WARNING:pkgcore:repos.conf: parsing '/etc/portage/repos.conf/jstein-overlay.conf': overriding DEFAULT section
Traceback (most recent call last):
  File "/usr/lib/python-exec/python3.11/nattka", line 8, in <module>
    sys.exit(setuptools_main())
             ^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/nattka/__main__.py", line 1066, in setuptools_main
    sys.exit(main(sys.argv[1:]))
             ^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/nattka/__main__.py", line 1056, in main
    return getattr(cmd, args.command.replace('-', '_'))()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/nattka/__main__.py", line 412, in make_package_list
    plist = dict(match_package_list(repo, b, only_new=True))
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/nattka/package.py", line 362, in match_package_list
    raise KeywordNoneLeft('package keywords in line with other '
nattka.package.KeywordNoneLeft: package keywords in line with other versions and none specified

$ cat /etc/portage/repos.conf/jstein-overlay.conf
[DEFAULT]
main-repo = gentoo

With
$ nattka make-package-list -a 'amd64' -s 'dev-util/reuse-2.1.0'

it returns

WARNING:pkgcore:repos.conf: parsing '/etc/portage/repos.conf/jstein-overlay.conf': overriding DEFAULT section
INFO:nattka:Iteration 1: running pkgcheck ...
WARNING:pkgcore:repos.conf: parsing '/etc/portage/repos.conf/jstein-overlay.conf': overriding DEFAULT section
INFO:nattka:New packages: dev-python/furo-2023.9.10 dev-python/recommonmark-0.7.1-r1 dev-python/sphinx-7.2.6 dev-python/sphinx-autodoc-typehints-1.25.2 dev-python/sphinxcontrib-apidoc-0.5.0
INFO:nattka:Package dev-python/sphinx-7.2.6 seems to be a red herring (already keyworded everywhere)
INFO:nattka:Package dev-python/furo-2023.9.10 seems to be a red herring (already keyworded everywhere)
INFO:nattka:Package dev-python/sphinx-autodoc-typehints-1.25.2 seems to be a red herring (already keyworded everywhere)
INFO:nattka:Package dev-python/recommonmark-0.7.1-r1 seems to be a red herring (already keyworded everywhere)
INFO:nattka:Iteration 1: verifying ...
WARNING:pkgcore:repos.conf: parsing '/etc/portage/repos.conf/jstein-overlay.conf': overriding DEFAULT section
INFO:nattka:Iteration 2: running pkgcheck ...
WARNING:pkgcore:repos.conf: parsing '/etc/portage/repos.conf/jstein-overlay.conf': overriding DEFAULT section
INFO:nattka:Time elapsed: 0:00:02.596405
INFO:nattka:Target CC: amd64@gentoo.org
WARNING:nattka:The package list contains newest versions visible.
WARNING:nattka:Please adjust the package list to desired versions.
INFO:nattka:Package list follows:
dev-util/reuse-2.1.0 amd64
dev-python/sphinxcontrib-apidoc-0.5.0 ^

I think it should not crash, but report, if -a is missing but required for nattka