Fix ruff warnings in caffe2 and functorch (#144182)

In preparation for upgrading ruff config to py3.9.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/144182
Approved by: https://github.com/malfet

functorch/dim/__init__.py

@@ -1,6 +1,7 @@
 import dis
 import inspect
-from typing import Sequence, Union
+from collections.abc import Sequence
+from typing import Union
 
 import functorch._C
 import torch

functorch/einops/_parsing.py

@@ -27,7 +27,11 @@ from __future__ import annotations
 
 import keyword
 import warnings
-from typing import Collection, List, Mapping, Optional, Set, Tuple, Union
+from typing import List, Optional, Set, Tuple, TYPE_CHECKING, Union
+
+
+if TYPE_CHECKING:
+    from collections.abc import Collection, Mapping
 
 
 _ellipsis: str = "\u2026"  # NB, this is a single unicode symbol. String is used as it is not a list, but can be iterated

functorch/einops/rearrange.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 import functools
-from typing import Callable, Dict, List, Sequence, Tuple, Union
+from typing import Callable, Dict, List, Tuple, TYPE_CHECKING, Union
 
 import torch
 from functorch._C import dim as _C
@@ -15,6 +15,10 @@ from ._parsing import (
 )
 
 
+if TYPE_CHECKING:
+    from collections.abc import Sequence
+
+
 __all__ = ["rearrange"]
 
 dims = _C.dims