code: def find_available_hosts_and_slots(self):
      result = self._execute_discovery_script()
  
      host_slots = {}
      lines = set(result.strip().split("\n"))
      for line in lines:
          host = line
          if ":" in line:
              host, slots = line.split(":")
              host_slots[host] = int(slots)
          # Make sure the host is not empty. The discovery script might
          # return empty string when all workers are not ready or available.
          elif host:
              host_slots[host] = self._default_slots
      return host_slots
  
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 2 for calling the HostDiscoveryScript obj's underlying member method code with example usage: obj.find_available_hosts_and_slots() and returns: host_slots