Method _update

traitlets/traitlets.py:419–423

(self, change: t.Any)

            self.updating = False

    def _update(self, change: t.Any) -> None:
        if self.updating:
            return
        with self._busy_updating():
            setattr(self.target[0], self.target[1], self._transform(change.new))

    def unlink(self) -> None:
        self.source[0].unobserve(self._update, names=self.source[1])