ModuleNotFoundError: Could not import module 'MistralForSequenceClassification'

[cqray1990]

System Info

transformers 5.10, 5.5.3

Who can help?

envs/verl_env/lib/python3.12/site-packages/transformers/utils/import_utils.py", line 2295, in getattr
raise ModuleNotFoundError(
ModuleNotFoundError: Could not import module 'MistralForSequenceClassification'. Are this object's requirements defined correctly?

Information

• The official example scripts
• My own modified scripts

Tasks

• An officially supported task in the examples folder (such as GLUE/SQuAD, ...)
• My own task or dataset (give details below)

Reproduction

envs/verl_env/lib/python3.12/site-packages/transformers/utils/import_utils.py", line 2295, in getattr
raise ModuleNotFoundError(
ModuleNotFoundError: Could not import module 'MistralForSequenceClassification'. Are this object's requirements defined correctly?

Expected behavior

.

[Sayyam-Akram]

Hi @cqray1990! 👋

I analyzed the issue and found that the ModuleNotFoundError for MistralForSequenceClassification is caused by the lazy loading mechanism in transformers/utils/import_utils.py.

When a user tries to access a model class that isn't explicitly defined in the __init__.py of the model's library, the __getattr__ method attempts to import the module but fails with a generic ModuleNotFoundError, obscuring the actual missing dependency (such as sentencepiece or accelerate).

I will fix this by improving the error handling in __getattr__ to catch the ModuleNotFoundError and re-raise it with a more informative message that explicitly shows the missing underlying requirement, helping users identify and install what is needed. I am submitting a PR for this!