What does asterisk (*) in a type mean?

[decorator-factory]

from typing import Generic, TypeVar, Union

T = TypeVar("T")

class _Unset():
    pass
_UNSET = _Unset()


class Foo(Generic[T]):
    def __init__(self):
        self._result: Union[T, _Unset] = _UNSET

    def is_set(self):
        return self._result is not _UNSET

When I hover over is_set in VSCode with Pylance, I see this:

What does bool* mean?

[erictraut]

Please refer to this documentation for details.