Fix pre-commit flake lint on GH (#819)

Summary: Pull Request resolved: #819

Reviewed By: galrotem

Differential Revision: D56832328

fbshipit-source-id: 5fc49d789302544ca09a6a956759ea4fc47b519c

Author: diego-urgell

torchtnt/utils/loggers/tensorboard.py

@@ -11,12 +11,10 @@
 
 import atexit
 import logging
-from typing import Any, Dict, List, Mapping, Optional, Union
-
-import torch.distributed as dist
+from typing import Any, Dict, Mapping, Optional, Union
 
 from torch.utils.tensorboard import SummaryWriter
-from torchtnt.utils.distributed import get_global_rank, PGWrapper
+from torchtnt.utils.distributed import get_global_rank
 from torchtnt.utils.loggers.logger import MetricLogger, Scalar
 
 logger: logging.Logger = logging.getLogger(__name__)