code: def fit(self, X, y, sample_weight=None):
      params_for_fitting = self.estimator_.get_params()
      self._get_alpha(X, y, sample_weight)
      params_for_fitting["ccp_alpha"] = self.alpha
      self.estimator_.set_params(**params_for_fitting)
      self.estimator_.fit(X, y)
  
imports: from copy import deepcopy
  from typing import List
  import numpy
  from sklearn import datasets
  from sklearn.base import BaseEstimator
  from sklearn.model_selection import cross_val_score, train_test_split
  from sklearn.tree import DecisionTreeClassifier
  from imodels.tree.hierarchical_shrinkage import HSTreeRegressor, HSTreeClassifier
  from imodels.util.tree import compute_tree_complexity
label_desc: Use image node_id 3 for calling the DecisionTreeCCPRegressor obj's underlying member method code with example usage: obj.fit(X, y, sample_weight) without return types