missing user_defined option in pyfluent setup options

[Abuse-Coding]

I want to hook an UDF to my project, however when I try to access user_defined as suggested from the documentation:
https://fluent.docs.pyansys.com/version/stable/api/solver/_autosummary/settings/setup.html#setup
I run into the following error:

AttributeError: 'setup' object has no attribute 'user_defined'.
The most similar names are: turbo_models

when I list the attributes of my setup, I see most of the documented attributes, but not all, anyone know how to access or enable user_defined attribute for the setup?

list(solver.settings.setup())

['general', 'models', 'materials', 'cell_zone_conditions', 'boundary_conditions', 'mesh_interfaces', 'dynamic_mesh', 'reference_values', 'reference_frames', 'named_expressions', 'turbo_models', 'profiles']

Even trying a workaround with using interpreted TUI-commands didn't help.

Thanks in advance.