class_docstr: Mixin abstract base class defining functionality for classifiers.
class_docstr_tok: ["Mixin","abstract","base","class","defining","functionality","for","classifiers","."]
docstr: Return the number of output classes.
  
  :return: Number of classes in the data.
code: def nb_classes(self) -> int:
      """
      Return the number of output classes.
  
      :return: Number of classes in the data.
      """
      return self._nb_classes
  
imports: from abc import ABC, ABCMeta, abstractmethod
  from typing import List, Optional, Union
  import numpy
  from art.estimators.estimator import BaseEstimator, NeuralNetworkMixin, LossGradientsMixin, DecisionTreeMixin
label_desc: Use image node_id 2 for calling the ClassifierMixin obj's underlying member method code with example usage: obj.nb_classes() and returns: self