Minor changes

- Move changelog entry up
- code style

Author: Daraan

CHANGELOG.md

@@ -19,10 +19,10 @@
 - Backport to Python 3.10 the ability to substitute `...` in generic `Callable`
 aliases that have a `Concatenate` special form as their argument.
   Patch by [Daraan](https://github.com/Daraan).
-- Fix error in subscription of `Unpack` aliases causing nested Unpacks 
-  to not be resolved correctly. Patch by [Daraan](https://github.com/Daraan).
 - Extended the `Concatenate` backport for Python 3.8-3.10 to now accept
   `Ellipsis` as an argument. Patch by [Daraan](https://github.com/Daraan).
+- Fix error in subscription of `Unpack` aliases causing nested Unpacks 
+  to not be resolved correctly. Patch by [Daraan](https://github.com/Daraan).
 
 # Release 4.12.2 (June 7, 2024)
 

src/typing_extensions.py

@@ -1803,7 +1803,6 @@ def __parameters__(self):
     if sys.version_info < (3, 11):
         _typing_ConcatenateGenericAlias = _ConcatenateGenericAlias
 
-
         class _ConcatenateGenericAlias(_typing_ConcatenateGenericAlias, _root=True):
             # needed for checks in collections.abc.Callable to accept this class
             __module__ = "typing"
@@ -1822,11 +1821,12 @@ def copy_with(self, params):
 # 3.8-3.9.2
 class _EllipsisDummy: ...
 
+
 # 3.8-3.10
 def _create_concatenate_alias(origin, parameters):
     if parameters[-1] is ... and sys.version_info < (3, 9, 2):
         # Hack: Arguments must be types, replace it with one.
-        parameters = parameters[:-1] + (_EllipsisDummy,)
+        parameters = (*parameters[:-1], _EllipsisDummy)
     if sys.version_info >= (3, 10, 2):
         concatenate = _ConcatenateGenericAlias(origin, parameters,
                                         _typevar_types=(TypeVar, ParamSpec),
@@ -1861,6 +1861,7 @@ def _concatenate_getitem(self, parameters):
                     parameters[-1])
     return _create_concatenate_alias(self, parameters)
 
+
 # 3.11+; Concatenate does not accept ellipsis in 3.10
 if sys.version_info >= (3, 11):
     Concatenate = typing.Concatenate