I think a list representation is more consistent with the text of PEP 612 and the runtime representation of Callable. We should change the runtime repr of ParamSpec generics to be more like Callable, because right now they're inconsistent:

>>> Callable[[int, str], bool]
typing.Callable[[int, str], bool]
>>> P = ParamSpec("P")
>>> T = TypeVar("T")
>>> class MyCallable(Generic[P, T]): pass
... 
>>> MyCallable[[int, str], bool]
__main__.MyCallable[(<class 'int'>, <class 'str'>), bool]
>>> get_args(Callable[[int, str], bool])
([<class 'int'>, <class 'str'>], <class 'bool'>)
>>> get_args(MyCallable[[int, str], bool])
((<class 'int'>, <class 'str'>), <class 'bool'>)