_xml_test.py fails to run independently

[xanderlent]

It seems like the lxml_parse function, first used in this code in 2022, isn't defined.

python3 -m blobfile._xml_test
Traceback (most recent call last):
xmltodict parse elapsed 1.5123482180060819
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/builddir/build/BUILD/python-blobfile-3.0.0-build/blobfile-3.0.0/blobfile/_xml_test.py", line 163, in <module>
    main()
    ~~~~^^
  File "/builddir/build/BUILD/python-blobfile-3.0.0-build/blobfile-3.0.0/blobfile/_xml_test.py", line 145, in main
    lxml_parse(expanded_resp_utf8, repeated_tags={"Blob", "BlobPrefix"})
    ^^^^^^^^^^
NameError: name 'lxml_parse' is not defined