Class Bool

traitlets/traitlets.py:3066–3138

A boolean (True, False) trait.

class Bool(TraitType[G, S]):
    """A boolean (True, False) trait."""

    default_value = False
    info_text = "a boolean"

    if t.TYPE_CHECKING:

        @t.overload
        def __init__(
            self: Bool[bool, bool | int],
            default_value: bool | Sentinel = ...,
            allow_none: Literal[False] = ...,
            read_only: bool | None = ...,
            help: str | None = ...,
            config: t.Any = ...,
            **kwargs: t.Any,
        ) -> None:
            ...

        @t.overload
        def __init__(
            self: Bool[bool | None, bool | int | None],
            default_value: bool | Sentinel | None = ...,
            allow_none: Literal[True] = ...,
            read_only: bool | None = ...,
            help: str | None = ...,
            config: t.Any = ...,
            **kwargs: t.Any,
        ) -> None:
            ...

        def __init__(
            self: Bool[bool | None, bool | int | None],
            default_value: bool | Sentinel | None = ...,
            allow_none: bool = ...,
            read_only: bool | None = ...,
            help: str | None = ...,
            config: t.Any = ...,
            **kwargs: t.Any,
        ) -> None:
            ...

    def validate(self, obj: t.Any, value: t.Any) -> G:
        if isinstance(value, bool):
            return value  # type:ignore[return-value]
        elif isinstance(value, int):
            if value == 1:
                return True  # type:ignore[return-value]
            elif value == 0:
                return False  # type:ignore[return-value]
        self.error(obj, value)

    def from_string(self, s: str) -> G:
        if self.allow_none and s == "None":
            return None  # type:ignore[return-value]
        s = s.lower()
        if s in {"true", "1"}: