code: def tearDown(self) -> None:
      super().tearDown()
      if not self._has_master_port:
          del os.environ["MASTER_PORT"]
      if not self._has_ucx_tls:
          del os.environ["UCX_TLS"]
  
imports: import os
  import sys
  import unittest
  from packaging.version import Version, parse
  import torch
  from torch import distributed
  from torch.utils import collect_env
  from torch.testing._internal import common_utils
  from torch.testing._internal import common_distributed
  from apex.transformer._ucc_util import HAS_UCC
label_desc: Use image node_id 2 for calling the UccDistributedTestBase obj's underlying member method code with example usage: obj.tearDown() without return types