"suds.TypeNotFound: Type not found: 'BVDefs'" error when trying to call service

[s-callan]

We have been using suds-0.3.9 to call the SOAP interface on our application, with no errors.
We have now moved from python 2.7 to Python 3.8 with suds-py3 1.4.4.1, and we are getting the error "suds.TypeNotFound: Type not found: 'BVDefs'".

The attached file contains a copy of the WSDl, the invoking python script, and the error stack back-trace
suds_type_not_found.zip