Python 3.10+: Optional[Type] or Type | None

PEP 604 covers these topics in the specification section.

The existing typing.Union and | syntax should be equivalent.

int | str == typing.Union[int, str]

The order of the items in the Union should not matter for equality.

(int | str) == (str | int)
(int | str | float) == typing.Union[str, float, int]

Optional values should be equivalent to the new union syntax

None | t == typing.Optional[t]

As @jonrsharpe comments, Union and Optional are not deprecated, so the Union and | syntax are acceptable.

Łukasz Langa, a Python core developer, replied on a YouTube live related to the Python 3.10 release that Type | None is preferred over Optional[Type] for Python 3.10+.