>>> from typing import TypeVarTuple, Unpack
>>> class Foo[*Ts]: ...
...
>>> Ts = TypeVarTuple("Ts")
>>> Bar = Foo[int, *Ts]
>>> Bar[*list[str]]
__main__.Foo[int, *list[str]]
>>> Bar[Unpack[list[str]]]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    Bar[Unpack[list[str]]]
    ~~~^^^^^^^^^^^^^^^^^^^
  File "/Users/alexw/dev/cpython/Lib/typing.py", line 394, in inner
    return func(*args, **kwds)
           ~~~~^^^^^^^^^^^^^^^
  File "/Users/alexw/dev/cpython/Lib/typing.py", line 1394, in __getitem__
    args = _unpack_args(args)
           ~~~~~~~~~~~~^^^^^^
  File "/Users/alexw/dev/cpython/Lib/typing.py", line 306, in _unpack_args
    subargs = getattr(arg, '__typing_unpacked_tuple_args__', None)
              ~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/alexw/dev/cpython/Lib/typing.py", line 1791, in __typing_unpacked_tuple_args__
    raise TypeError("Unpack[...] must be used with a tuple type")
TypeError: Unpack[...] must be used with a tuple type