class_docstr: Base class for a dynamic classifier selection (dcs) and
     dynamic ensemble selection (des) methods.
  
  All DCS and DES techniques should inherit from this class.
  
  Warning: This class should not be used directly.
  Use derived classes instead.
docstr: Checks if each base classifier in the pool implements the
  predict_proba method.
  
  Raises
  -------
  ValueError
      If the base classifiers do not implements the predict_proba method.
docstr_tok: ["Checks","if","each","base","classifier","in","the","pool","implements","the","predict_proba","method",".","Raises","--","--","--","-","ValueError","If","the","base","classifiers","do","not","implements","the","predict_proba","method","."]
code: def _check_predict_proba(self):
      """Checks if each base classifier in the pool implements the
      predict_proba method.
  
      Raises
      -------
      ValueError
          If the base classifiers do not implements the predict_proba method.
      """
      for clf in self.pool_classifiers_:
          if "predict_proba" not in dir(clf):
              raise ValueError(
                  "All base classifiers should output probability estimates"
              )
  
imports: import functools
  import math
  import warnings
  from abc import abstractmethod, ABCMeta
  import numpy
  from scipy.stats import mode
  from sklearn.base import BaseEstimator, ClassifierMixin
  from sklearn.ensemble import BaseEnsemble, BaggingClassifier
  from sklearn.model_selection import train_test_split
  from sklearn.neighbors import KNeighborsClassifier
  from sklearn.preprocessing import LabelEncoder, normalize
  from sklearn.utils.validation import check_X_y, check_is_fitted, check_array, check_random_state
  from deslib.util import KNNE
  from deslib.util import faiss_knn_wrapper
  from deslib.util.dfp import frienemy_pruning_preprocessed
  from deslib.util.instance_hardness import hardness_region_competence
label_desc: Use image node_id 33 for calling the BaseDS obj's underlying member method code with example usage: obj._check_predict_proba() without return types