code: def _get_leaf_node_map(self):
      if len(self._nodes) >= len(self._leaf_node_map):
          for n in self._nodes:
              self._leaf_node_map[n.nid] = n.is_leaf
  
imports: import numpy
  import pandas
  from fate.arch import Context
  from fate.arch.dataframe import DataFrame
  from fate.ml.ensemble.learner.decision_tree.tree_core.splitter import SplitInfo
  from typing import List
  import logging
label_desc: Use image node_id 4 for calling the DecisionTree obj's underlying member method code with example usage: obj._get_leaf_node_map() without return types