Scikit-learn: Erreur d'importation lors du chargement d'un modèle décapé extrait de Pipeline

Décrivez le bogue

Le décapage d'un RandomForestClassifier extrait d'un pipeline sklearn semble entraîner un ModuleNotFoundError lors du chargement dans un autre bloc-notes. Le module errant existe, mais est introuvable : sklearn.ensemble._forest .

Étapes/Code à reproduire

from sklearn.ensemble import RandomForestClassifier
from sklearn.pipeline import make_pipeline
import pickle
import numpy as np


pipeline = make_pipeline(
    # Other steps in pipeline as well
    RandomForestClassifier(),
)

# Create some fake data
X_train = np.array([[2,8,5],[4,7,2],[1,9,4]])
y_train = np.array([26, 29, 18])
# Train the model
pipeline.fit(X_train, y_train)

# Pickle the model
model = pipeline.named_steps['randomforestclassifier']
outfile = open("model.pkl", "wb")
pickle.dump(model, outfile)
outfile.close()

Dans un autre cahier :

from sklearn.ensemble import RandomForestClassifier
import pickle


# Attempt to load the pickled model in another file / notebook:
infile = open("model.pkl", "rb")
model = pickle.load(infile)
infile.close()

# It's lonely over here
model

Résultats attendus

RandomForestClassifier(bootstrap=True, ccp_alpha=0.0, class_weight=None,
                       criterion='gini', max_depth=None, max_features='auto',
                       max_leaf_nodes=None, max_samples=None,
                       min_impurity_decrease=0.0, min_impurity_split=None,
                       min_samples_leaf=1, min_samples_split=2,
                       min_weight_fraction_leaf=0.0, n_estimators=100,
                       n_jobs=None, oob_score=False, random_state=None,
                       verbose=0, warm_start=False)

Résultats actuels

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
<ipython-input-20-c8d1783e8b58> in <module>
      5 # Attempt to load the pickled model in another file / notebook:
      6 infile = open("model.pkl", "rb")
----> 7 model = pickle.load(infile)
      8 infile.close()

ModuleNotFoundError: No module named 'sklearn.ensemble._forest'

Versions

System:
    python: 3.7.4 (default, Oct  9 2019, 16:55:50)  [GCC 7.4.0]
executable: /usr/local/bin/python3.7
   machine: Linux-4.15.0-88-generic-x86_64-with-debian-buster-sid

Python deps:
       pip: 19.3
setuptools: 40.8.0
   sklearn: 0.21.3
     numpy: 1.17.2
     scipy: 1.3.1
    Cython: None
    pandas: 0.25.1

EDIT : Correction de la description