code: def get_children_left(self):
      return self._calculate_children(
          self.__class__.LEFT_CHILDREN_COLUMN
      )
  
imports: import json
  import math
  from collections import defaultdict
  from typing import List, Mapping
  import numpy
  from dtreeviz.models.shadow_decision_tree import VisualisationNotYetSupportedError
  from dtreeviz.models.shadow_decision_tree import ShadowDecTree
  from dtreeviz import utils
  import xgboost
  from xgboost.core import Booster
label_desc: Use image node_id 6 for calling the ShadowXGBDTree obj's underlying member method code with example usage: obj.get_children_left() and returns: self