Adding default parameter value with type hint in Python

Question

If I have a function like this:

def foo(name, opts={}):
  pass

And I want to add type hints to the parameters, how do I do it? The way I as

Answer 1

If you're using typing (introduced in Python 3.5) you can use typing.Optional, where Optional[X] is equivalent to Union[X, None]. It is used to signal that the explicit value of None is allowed . From typing.Optional:

def foo(arg: Optional[int] = None) -> None:
    ...