Optional typing for more than a single type

Since the documentation only uses Optional with a single type (Optional[X]), I was wondering if Union is required if I have an argument that accepts either a string, a list, or None.

def func(
    arg: Optional[str, list]
)

def func(
    arg: Optional[Union[str, list]]
)

>Solution :

Since Optional[...] is shorthand for Union[..., None], they are essentially the same, and you can just use Optional[str, list], since that’s the same as Union[str, list, None].