def _next_controller_changed(self, old, new):

        if old is not None:
            old.on_trait_change(
                self._on_controller_complete, 'complete', remove=True
            )

        if new is not None:
            new.on_trait_change(
                self._on_controller_complete, 'complete'
            )

        self._update()

        return

    #### Dynamic ####
Called when the next controller is changed.
dataset/ETHPy150Open enthought/pyface/pyface/wizard/chained_wizard_controller.py/ChainedWizardController._next_controller_changed