code: def test_get_ranks(self):
      role_infos = [
          _RoleInstanceInfo("parameter_server", 0, 4),
          _RoleInstanceInfo("trainer", 1, 1),
          _RoleInstanceInfo("trainer", 2, 2),
          _RoleInstanceInfo("trainer", 3, 3),
          _RoleInstanceInfo("parameter_server", 4, 5),
      ]
      spec = self._get_worker_spec(
          max_restarts=3,
          monitor_interval=0.1,
          role="not_used",
          local_world_size=8,
      )
      agent = TestAgent(spec)
      total_sum, ranks = agent._get_ranks(
          role_infos, 0, 0, len(role_infos)
      )
      self.assertEqual(15, total_sum)
      self.assertEqual([0, 1, 2, 3], list(ranks))
  
imports: import signal
  import unittest
  import uuid
  from typing import Any, Dict
  from unittest.mock import call, patch, MagicMock
  import torch.distributed.elastic.rendezvous.registry
  from torch.distributed.elastic.agent.server.api import RunResult, SimpleElasticAgent, WorkerGroup, WorkerSpec, WorkerState, _get_fq_hostname, _RoleInstanceInfo
  from torch.distributed.elastic.multiprocessing import SignalException
  from torch.distributed.elastic.multiprocessing.errors import ProcessFailure
  from torch.distributed.elastic.rendezvous import RendezvousHandler, RendezvousParameters
  from torch.distributed.elastic.utils.distributed import get_free_port
  from torch.testing._internal.common_utils import run_tests
label_desc: Use image node_id 22 for calling the SimpleElasticAgentTest obj's underlying member method code with example usage: obj.test_get_ranks() without return types