Drops states from a stash. This is an alias for move(), with defaults for the stashes.

        :param filter_func: Drop states that match this filter. Should be a function that takes
                            a state and returns True or False. (default: drop all states)
        :param stash:       Drop matching states from this stash. (default: 'active')

        :returns:           The simulation manager, for chaining.
        :rtype:             SimulationManager

def drop(self, filter_func=None, stash='active'):
        """
        Drops states from a stash. This is an alias for move(), with defaults for the stashes.

        :param filter_func: Drop states that match this filter. Should be a function that takes
                            a state and returns True or False. (default: drop all states)
        :param stash:       Drop matching states from this stash. (default: 'active')

        :returns:           The simulation manager, for chaining.
        :rtype:             SimulationManager
        """
        return self.move(stash, self.DROP, filter_func=filter_func)