spdx_lookup is unmaintained
https://github.com/bbqsrc/spdx-lookup-python and https://github.com/bbqsrc/spdx-python are archived. They also have no tests, so it is hard to determine if they are still working correctly.
I suggest using https://github.com/spdx/tools-python instead, and maybe https://github.com/nexB/license-expression .