bg_import doc example fails

[pbavinck]

Following the README:

When executing the bg_import command with the -v parameter to retrieve an explanation of individual parameters, the command fails with the following traceback:

python3 bg_import/business_glossary_import.py -h
Traceback (most recent call last):
  File "/home/peter/dataplex-labs/dataplex-quickstart-labs/00-resources/scripts/python/business-glossary-import/bg_import/business_glossary_import.py", line 6, in <module>
    import categories_csv_parser
  File "/home/peter/dataplex-labs/dataplex-quickstart-labs/00-resources/scripts/python/business-glossary-import/bg_import/categories_csv_parser.py", line 13, in <module>
    import error
  File "/home/peter/dataplex-labs/dataplex-quickstart-labs/00-resources/scripts/python/business-glossary-import/bg_import/error.py", line 20, in <module>
    class Error(abc.ABC):
  File "/home/peter/dataplex-labs/dataplex-quickstart-labs/00-resources/scripts/python/business-glossary-import/bg_import/error.py", line 42, in Error
    message: str | None = None,
TypeError: unsupported operand type(s) for |: 'type' and 'NoneType'

Running the import with a CSV file, same error.
Python version: 3.9.2