_config.main.py lint

[peter-spencer-ons]

From make check-python:

src/occupational_classification/_config/main.py:88:12: PLW0603 Using the global statement to update _config is discouraged

From poetry run pylint --verbose .:

src/occupational_classification/_config/main.py:88:4: W0603: Using the global statement (global-statement) % formatting in logging functions (logging-fstring-interpolation)