code: def get_tree(self, idx):
      return self._trees[idx]
  
file_path: FATE/python/fate/ml/ensemble/algo/secureboost/hetero/host.py
imports: import random
  import os
  from fate.ml.ensemble.learner.decision_tree.hetero.host import HeteroDecisionTreeHost
  from fate.ml.ensemble.algo.secureboost.hetero._base import HeteroBoostingTree
  from fate.arch import Context
  from fate.arch.dataframe import DataFrame
  from fate.ml.ensemble.utils.binning import binning
  from fate.ml.ensemble.algo.secureboost.common.predict import predict_leaf_host
  from fate.ml.ensemble.learner.decision_tree.tree_core.decision_tree import GUEST_FEAT_ONLY, ALL_FEAT
  import logging
label_desc: Use image node_id 2 for calling the HeteroSecureBoostHost obj's underlying member method code with example usage: obj.get_tree(idx) and returns: self