* A required positional-only argument representing the deprecation message.

* Two keyword-only arguments, ``category`` and ``stacklevel``, controlling

runtime behavior (see under "Runtime behavior" below).

runtime behavior. These are not relevant to type checker behavior so they are

not further described in this specification.

The positional-only argument is of type ``str`` and contains a message that should

be shown by the type checker when it encounters a usage of the decorated object.