code: def fit(self, X, y, feature_costs=None):
      self.n_classes_ = len(set(y))
      self.n_features = X.shape[1]
      self.feature_costs_ = imodels.util.tree._validate_feature_costs(
          feature_costs, self.n_features
      )
      self.root = self._grow_tree(X, y)
  
imports: from sklearn.tree._tree import Tree
  from sklearn.tree import DecisionTreeClassifier, DecisionTreeRegressor
  from sklearn.base import ClassifierMixin, RegressorMixin
  from sklearn import __version__
  from collections import namedtuple
  import pandas
  import numpy
  from collections import namedtuple
  from sklearn import __version__
  from sklearn.base import ClassifierMixin, RegressorMixin
  from sklearn.tree import DecisionTreeClassifier, DecisionTreeRegressor
  from sklearn.tree._tree import Tree
  import imodels.util.tree
label_desc: Use image node_id 2 for calling the CustomDecisionTreeClassifier obj's underlying member method code with example usage: obj.fit(X, y, feature_costs) without return types