Branches of the if statement have similar implementation (#10475)

* Branches of the `if` statement have similar implementation

Issue introduced by 16b53ac / #8937.

It looks like the `sys.version_info >= (3, 11)` test is incorrect, as
`typing.TypeAlias`  was added in version 3.10, not 3.11:
	https://docs.python.org/3/library/typing.html#typing.TypeAlias

* Branches of the `if` statement have similar implementation

Introduced by 17933e7 / #7426.

Author: DimitriPapadopoulos

asv_bench/benchmarks/dataset_io.py

@@ -678,13 +678,7 @@ def open(
                 lock: xr.backends.locks.SerializableLock | None = None,
                 autoclose: bool = False,
             ):
-                if lock is None:
-                    if mode == "r":
-                        locker = xr.backends.locks.SerializableLock()
-                    else:
-                        locker = xr.backends.locks.SerializableLock()
-                else:
-                    locker = lock
+                locker = lock or xr.backends.locks.SerializableLock()
 
                 manager = xr.backends.CachingFileManager(
                     xr.backends.DummyFileManager,

xarray/namedarray/_typing.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import sys
 from collections.abc import Callable, Hashable, Iterable, Mapping, Sequence
 from enum import Enum
 from types import EllipsisType, ModuleType
@@ -20,10 +19,7 @@
 import numpy as np
 
 try:
-    if sys.version_info >= (3, 11):
-        from typing import TypeAlias
-    else:
-        from typing import TypeAlias
+    from typing import TypeAlias
 except ImportError:
     if TYPE_CHECKING:
         raise