docs: def unstash(self, filter_func=None, to_stash='active', from_stash='stashed'):
          """
          Unstash some states. This is an alias for move(), with defaults for the stashes.
  
          :param filter_func: Unstash states that match this filter. Should be a function that
                              takes a state and returns True or False. (default: unstash all states)
          :param from_stash:  take matching states from this stash. (default: 'stashed')
          :param to_stash:    put matching states into this stash. (default: 'active')
  
          :returns:           The simulation manager, for chaining.
          :rtype:             SimulationManager
          """
          return self.move(from_stash, to_stash, filter_func=filter_func)