AttributeError: 'lxml.etree.QName' object has no attribute 'signature'

[akent]

Problem parsing the WSDL, traceback:

  File "/usr/local/Cellar/python@3.9/3.9.2/Frameworks/Python.framework/Versions/3.9/lib/python3.9/runpy.py", line 197, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/local/Cellar/python@3.9/3.9.2/Frameworks/Python.framework/Versions/3.9/lib/python3.9/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/Users/akent/Library/Caches/pypoetry/virtualenvs/atis-py3-X0QpvnV6-py3.9/lib/python3.9/site-packages/zeep/__main__.py", line 92, in <module>
    main(args)
  File "/Users/akent/Library/Caches/pypoetry/virtualenvs/atis-py3-X0QpvnV6-py3.9/lib/python3.9/site-packages/zeep/__main__.py", line 87, in main
    client.wsdl.dump()
  File "/Users/akent/Library/Caches/pypoetry/virtualenvs/atis-py3-X0QpvnV6-py3.9/lib/python3.9/site-packages/zeep/wsdl/wsdl.py", line 124, in dump
    value = type_obj.signature(schema=self.types)
  File "/Users/akent/Library/Caches/pypoetry/virtualenvs/atis-py3-X0QpvnV6-py3.9/lib/python3.9/site-packages/zeep/xsd/types/complex.py", line 494, in signature
    part = element.signature(schema, standalone=False)
  File "/Users/akent/Library/Caches/pypoetry/virtualenvs/atis-py3-X0QpvnV6-py3.9/lib/python3.9/site-packages/zeep/xsd/elements/indicators.py", line 264, in signature
    value = element.signature(schema, standalone=False)
  File "/Users/akent/Library/Caches/pypoetry/virtualenvs/atis-py3-X0QpvnV6-py3.9/lib/python3.9/site-packages/zeep/xsd/elements/element.py", line 315, in signature
    value = self.type.signature(schema, standalone=False)
  File "/Users/akent/Library/Caches/pypoetry/virtualenvs/atis-py3-X0QpvnV6-py3.9/lib/python3.9/site-packages/zeep/xsd/types/collection.py", line 54, in signature
    return self.item_type.signature(schema) + "[]"
AttributeError: 'lxml.etree.QName' object has no attribute 'signature'

Please provide the following information:

1. The version of zeep (or if you are running master the commit hash/date)

4.0.0

2. The WSDL you are using

https://www.airservicesaustralia.com/naips/briefing-service?wsdl

3. A runnable example script which exposes the problem.

python3 -m zeep "https://www.airservicesaustralia.com/naips/briefing-service?wsdl"

Happy to help debug further or fix, just a bit lost! Thanks for any insight you can offer!