I'm not sure whether this is a result of how the Rust mappings are done, but the lingua classes appear to Python to be in the builtins module:
from lingua import IsoCode639_1, LanguageDetectorBuilder
print(f"{IsoCode639_1.__module__=} {LanguageDetectorBuilder.__module__=}")
IsoCode639_1.__module__='builtins' LanguageDetectorBuilder.__module__='builtins'
This means that, for example, pylint gets confused:
% pylint lingua_test.py
************* Module lingua_test
lingua_test.py:1:0: E0611: No name 'IsoCode639_1' in module 'lingua' (no-name-in-module)
lingua_test.py:1:0: E0611: No name 'LanguageDetectorBuilder' in module 'lingua' (no-name-in-module)