code: def find_available_hosts_and_slots(self):
      hostlist = next(self._generator)
      # Ensure discovery waits for the previous set to register
      self._wait_for_previous_set_registration(hostlist)
  
      hosts = {}
      for item in hostlist:
          host, slots = item.split(":")
          slots = int(slots)
          hosts[host] = slots
  
      return hosts
  
imports: from contextlib import contextmanager
  import psutil
  import os
  import socket
  import time
  import mock
  import pytest
  import ray
  from horovod.common.util import gloo_built
  from horovod.runner.elastic.discovery import HostDiscovery
  from horovod.ray.elastic import ElasticRayExecutor, RayHostDiscovery
label_desc: Use image node_id 3 for calling the SimpleTestDiscovery obj's underlying member method code with example usage: obj.find_available_hosts_and_slots() and returns: hosts