Comment 2 for bug 1959918

There are other instances of collections, which I fixed with the attached patch, or so I think.

But the build fails elsewhere, also during tests (and it's a long build, 6h!): https://launchpadlibrarian.net/584187637/buildlog_ubuntu-jammy-amd64.keras_2.3.1+dfsg-3ubuntu1~ppa2_BUILDING.txt.gz

For example:
            assert 'group3' in group2
            group3 = group2['group3']
> assert group3['y'] == [b'efg', b'hij', b'klmn']
E ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

and

        if 'keras_version' in f.attrs:
> original_keras_version = f.attrs['keras_version'].decode('utf8')
E AttributeError: 'str' object has no attribute 'decode'