Add BaseEstimator inheritance

Author: Huy Pham

hiclass/ConstantClassifier.py

@@ -1,9 +1,10 @@
 """Constant classifier if there is only one class in the training set."""
 
 import numpy as np
+from sklearn.base import BaseEstimator
 
 
-class ConstantClassifier:
+class ConstantClassifier(BaseEstimator):
     """A classifier that always returns the only label seen during fit."""
 
     def fit(self, X, y, sample_weight=None):

hiclass/_calibration/BinaryCalibrator.py

@@ -1,8 +1,9 @@
 import abc
 import numpy as np
+from sklearn.base import BaseEstimator
 
 
-class _BinaryCalibrator(abc.ABC):
+class _BinaryCalibrator(abc.ABC, BaseEstimator):
     @abc.abstractmethod
     def fit(
         self, y: np.ndarray, scores: np.ndarray, X: np.ndarray = None