Class trick not needed for 3.11

Author: Daraan

src/typing_extensions.py

@@ -2657,7 +2657,9 @@ def __init__(self, getitem):
             self.__doc__ = _UNPACK_DOC
 
     class _UnpackAlias(typing._GenericAlias, _root=True):
-        __class__ = typing.TypeVar
+        if sys.version_info[:2] < (3, 11):
+            # needed for compatibility with Generic[Unpack[Ts]]
+            __class__ = typing.TypeVar
 
         @property
         def __typing_unpacked_tuple_args__(self):