code: def test_explicit_partition_servers(self) -> None:
      ranks = ProcessRanks.from_num_invocations(5, 3)
      self.assertEqual(ranks.trainers, [0, 1, 2, 3, 4])
      self.assertEqual(ranks.parameter_servers, [5, 6, 7, 8, 9])
      self.assertEqual(ranks.parameter_clients, [10, 11, 12, 13, 14])
      self.assertEqual(ranks.lock_server, 15)
      self.assertEqual(ranks.partition_servers, [16, 17, 18])
  
imports: from unittest import main, TestCase
  from torchbiggraph.distributed import ProcessRanks
label_desc: Use image node_id 3 for calling the TestProcessRanks obj's underlying member method code with example usage: obj.test_explicit_partition_servers() without return types