Python 3 type hinting for None?

Question

def foo(
        hello: str=\'world\', bar: str=None,
        another_string_or_None: str|????=None):
    pass

I\'m trying to set a type hint in Py

Answer 1

I know this question is considered answered thanks to @mbdevpl, however, I've wanted to add that type(None) is how you get the actual for None type, this can be useful for example in an if statement check like:

if isinstance(x_var, type(None)):
    pass

and since python3.5, you can also use do Union of a bunch of types with None as shown here:

x_var: typing.Union[str, None]
y_var: typing.Union[Dict, List, None]

this is equivalent to:

x_var: typing.Optional[str]
y_var: typing.Optional[typing.Union[Dict, List]]