:DEPRECATED:
        Periodically save the state of the environment and the agents.

def save_state(self):
        '''
        :DEPRECATED:
        Periodically save the state of the environment and the agents.
        '''
        self._save_state()
        while self.peek() != simpy.core.Infinity:
            delay = max(self.peek() - self.now, self.interval)
            utils.logger.debug('Step: {}'.format(self.now))
            ev = self.event()
            ev._ok = True
            # Schedule the event with minimum priority so
            # that it executes before all agents
            self.schedule(ev, -999, delay)
            yield ev
            self._save_state()