class_docstr: tracker for rabit
code: def _get_tree(
      self, n_workers: int
  ) -> Tuple[_TreeMap, Dict[int, int]]:
      tree_map: _TreeMap = {}
      parent_map: Dict[int, int] = {}
      for r in range(n_workers):
          tree_map[r] = self._get_neighbor(r, n_workers)
          parent_map[r] = (r + 1) // 2 - 1
      return tree_map, parent_map
  
imports: import socket
  import struct
  import logging
  from threading import Thread
  import argparse
  import sys
  from typing import Dict, List, Tuple, Union, Optional, Set
label_desc: Use image node_id 5 for calling the RabitTracker obj's underlying member method code with example usage: obj._get_tree(n_workers) and returns: tree_map,  parent_map