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