code: def host_assignment_order(self):
      return self._host_assignment_order
  
imports: import io
  import logging
  import random
  import threading
  import time
  from collections import defaultdict
  from horovod.runner.common.util import safe_shell_exec
  from horovod.runner.elastic.worker import HostUpdateResult
label_desc: Use image node_id 4 for calling the DiscoveredHosts obj's underlying member method code with example usage: obj.host_assignment_order() and returns: self