class_docstr: Tracker module for PS
class_docstr_tok: ["Tracker","module","for","PS"]
code: def slave_envs(self):
      if self.cmd is None:
          return {}
      else:
          return {
              "DMLC_PS_ROOT_URI": self.hostIP,
              "DMLC_PS_ROOT_PORT": self.port,
          }
  
imports: from __future__ import absolute_import
  import os
  import sys
  import socket
  import struct
  import subprocess
  import argparse
  import time
  import logging
  from threading import Thread
label_desc: Use image node_id 3 for calling the PSTracker obj's underlying member method code with example usage: obj.slave_envs() and returns: dict, dict