from typing import Callable, TypeVar, overload from attrs import _ConverterType _T = TypeVar("_T") def pipe(*validators: _ConverterType) -> _ConverterType: ... def optional(converter: _ConverterType) -> _ConverterType: ... @overload def default_if_none(default: _T) -> _ConverterType: ... @overload def default_if_none(*, factory: Callable[[], _T]) -> _ConverterType: ... def to_bool(val: str) -> bool: ...