This function is passed to each SelectableObject as a callback
        The SelectableObjects have to call it once there are ready

def _exit_door(self, _input):
        """This function is passed to each SelectableObject as a callback
        The SelectableObjects have to call it once there are ready"""
        self.results.append(_input)
        if self._ended:
            return
        self._ended = True
        self._release_all()