Fix TypeError in MutableTorchTensorRTModule on Python 3.9 (#3094)

Author: HolyWu

py/torch_tensorrt/dynamo/runtime/_MutableTorchTensorRTModule.py

@@ -1,7 +1,7 @@
 import logging
 from copy import deepcopy
 from enum import Enum, auto
-from typing import Any, Collection, Dict, Iterator, List, Optional, Set, Tuple, Union
+from typing import Any, Collection, Dict, Iterator, List, Optional, Set, Union
 
 import numpy as np
 import torch
@@ -57,9 +57,9 @@ def __init__(
         disable_tf32: bool = _defaults.DISABLE_TF32,
         assume_dynamic_shape_support: bool = _defaults.ASSUME_DYNAMIC_SHAPE_SUPPORT,
         sparse_weights: bool = _defaults.SPARSE_WEIGHTS,
-        enabled_precisions: (
-            Set[torch.dtype | dtype] | Tuple[torch.dtype | dtype]
-        ) = _defaults.ENABLED_PRECISIONS,
+        enabled_precisions: Set[
+            Union[torch.dtype, dtype]
+        ] = _defaults.ENABLED_PRECISIONS,
         engine_capability: EngineCapability = _defaults.ENGINE_CAPABILITY,
         make_refitable: bool = _defaults.MAKE_REFITABLE,
         debug: bool = _defaults.DEBUG,