new_contents: from osim.env import RunEnv
  import opensim
  
  env = RunEnv(visualize=True)
  observation = env.reset(seed=0)
  
  s = 0
  for s in range(50000):
      d = False
  
      if s == 30:
          state_old = opensim.State(env.osim_model.state)
          print("State stored")
          print(state_old)
      if s % 50 == 49:
          env.osim_model.revert(state_old)
          state_old = opensim.State(state_old)
          print("Rollback")
          print(state_old)
  
      o, r, d, i = env.step(env.action_space.sample())
  
subject: Rollback to some state #79