1from typing import TypeVar, Optional, Callable, overload 2from . import _ConverterType 3 4_T = TypeVar("_T") 5 6def optional( 7 converter: _ConverterType[_T] 8) -> _ConverterType[Optional[_T]]: ... 9@overload 10def default_if_none(default: _T) -> _ConverterType[_T]: ... 11@overload 12def default_if_none(*, factory: Callable[[], _T]) -> _ConverterType[_T]: ... 13