Deprecated alias to

Callable[[int], str] signifies a function that takes a single parameter of type int and returns a str.

The subscription syntax must always be used with exactly two values: the argument list and the return type. The argument list must be a list of types, a ParamSpec, Concatenate or ellipsis. The return type must be a single type.

There is no syntax to indicate optional or keyword arguments; such function types are rarely used as callback types.

alias of Callable