class_docstr: Wrapper class for scikit-learn Decision Tree Regressor models.
code: def _get_leaf_nodes(
      self, node_id, i_tree, class_label, box
  ) -> List["LeafNode"]:
      from art.metrics.verification_decisions_trees import (
          LeafNode,
          Box,
          Interval,
      )
  
      leaf_nodes: List[LeafNode] = []
  
      if self.get_left_child(node_id) != self.get_right_child(node_id):
          node_left = self.get_left_child(node_id)
          node_right = self.get_right_child(node_id)
  
          box_left = deepcopy(box)
          box_right = deepcopy(box)
  
          feature = self.get_feature_at_node(node_id)
          box_split_left = Box(
              intervals={
                  feature: Interval(
                      -np.inf, self.get_threshold_at_node(node_id)
                  )
              }
          )
          box_split_right = Box(
              intervals={
                  feature: Interval(
                      self.get_threshold_at_node(node_id), np.inf
                  )
              }
          )
  
          if box.intervals:
              box_left.intersect_with_box(box_split_left)
              box_right.intersect_with_box(box_split_right)
          else:
              box_left = box_split_left
              box_right = box_split_right
  
          leaf_nodes += self._get_leaf_nodes(
              node_left, i_tree, class_label, box_left
          )
          leaf_nodes += self._get_leaf_nodes(
              node_right, i_tree, class_label, box_right
          )
  
      else:
          leaf_nodes.append(
              LeafNode(
                  tree_id=i_tree,
                  class_label=class_label,
                  node_id=node_id,
                  box=box,
                  value=self.get_values_at_node(node_id)[0, 0],
              )
          )
  
      return leaf_nodes
  
imports: import logging
  import os
  import pickle
  from copy import deepcopy
  from typing import List, Optional, Tuple, Union, TYPE_CHECKING
  import numpy
  from art.estimators.scikitlearn import ScikitlearnEstimator
  from art.estimators.regression.regressor import RegressorMixin
  from art import config
label_desc: Use image node_id 9 for calling the ScikitlearnDecisionTreeRegressor obj's underlying member method code with example usage: obj._get_leaf_nodes(node_id, i_tree, class_label, box) and returns: leaf_nodes