Class Callable

traitlets/traitlets.py:4313–4327

A trait which is callable. Notes ----- Classes are callable, as are instances with a __call__() method.

class Callable(TraitType[t.Callable[..., t.Any], t.Callable[..., t.Any]]):
    """A trait which is callable.

    Notes
    -----
    Classes are callable, as are instances
    with a __call__() method."""

    info_text = "a callable"

    def validate(self, obj: t.Any, value: t.Any) -> t.Any:
        if callable(value):
            return value
        else:
            self.error(obj, value)