unable to load a saved `WeibullAFTFitter` model

[deven-gqc]

Hello, I have saved a WeibullAFTFitter model as a pkl file. Versions being used: Python: 3.9.16 lifelines: 0.27.7

Here is the entire stacktrace. I am able to load CoxPHFitter with a problem, the code only breaks with WeibullAFTFitter

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[21], line 2
      1 for w in weibull_files:
----> 2   load_saved_model(w)

File ~/git/gqc/loe_coe_app_deven_fork/pipe_breaks/tl/loader.py:12, in load_saved_model(pkl_file)
      6 def load_saved_model(pkl_file: str | Path):
      7   """Load trained model
      8 
      9   Args:
     10       pkl_file (str | Path): path to the saved model
     11   """
---> 12   model = pickle.load(open(pkl_file, 'rb'))
     13   return model

File ~/mambaforge/envs/lifelines/lib/python3.9/site-packages/formulaic/formula.py:277, in Formula.__getattr__(self, attr)
    275 def __getattr__(self, attr: str) -> Any:
    276     # Keep substructures wrapped to retain access to helper functions.
--> 277     subformula = super().__getattr__(attr)
    278     if attr != "root":
    279         return Formula.from_spec(subformula)

File ~/mambaforge/envs/lifelines/lib/python3.9/site-packages/formulaic/parser/types/structured.py:405, in Structured.__getattr__(self, attr)
    403 def __getattr__(self, attr: str) -> Any:
    404     if attr.startswith("_"):
--> 405         raise AttributeError(attr)
    406     if attr in self._structure:
    407         return self._structure[attr]

AttributeError: __dict__

[CamDavidsonPilon]

I'm not able to repro this. Can you share you dump code, and what verion of formualic you are using?