Turn off any active document hold and apply any collected events.

        Returns:
            None

def unhold(self):
        ''' Turn off any active document hold and apply any collected events.

        Returns:
            None

        '''
        # no-op if we are already no holding
        if self._hold is None: return

        self._hold = None
        events = list(self._held_events)
        self._held_events = []

        for event in events:
            self._trigger_on_change(event)