Error when running the tutorial code

Hi,
I run the tutorial code by python tutorial_PPO.py, but I got an error:
```
Traceback (most recent call last):
File "/data/projects/20240627/ElegantRL/helloworld/tutorial_PPO.py", line 65, in
train_ppo_for_pendulum(GPU_ID)
File "/data/projects/20240627/ElegantRL/helloworld/tutorial_PPO.py", line 31, in train_ppo_for_pendulum
train_agent(args)
File "/data/projects/20240627/ElegantRL/helloworld/run.py", line 40, in train_agent
buffer_items = agent.explore_env(env, horizon_len)
File "/data/projects/20240627/ElegantRL/helloworld/agent.py", line 207, in explore_env
state = torch.as_tensor(ary_state, dtype=torch.float32, device=self.device)
ValueError: expected sequence of length 3 at dim 1 (got 0)
```
To solve this problem, I change the code in agent.py:
change
`state = torch.as_tensor(ary_state, dtype=torch.float32, device=self.device)`
into
`state = torch.as_tensor(ary_state[0], dtype=torch.float32, device=self.device)`
but I got a new error:
```
Traceback (most recent call last):
File "/data/projects/20240627/ElegantRL/helloworld/tutorial_PPO.py", line 65, in
train_ppo_for_pendulum(GPU_ID)
File "/data/projects/20240627/ElegantRL/helloworld/tutorial_PPO.py", line 31, in train_ppo_for_pendulum
train_agent(args)
File "/data/projects/20240627/ElegantRL/helloworld/run.py", line 40, in train_agent
buffer_items = agent.explore_env(env, horizon_len)
File "/data/projects/20240627/ElegantRL/helloworld/agent.py", line 211, in explore_env
ary_state, reward, done, _ = env.step(ary_action)
File "/data/projects/20240627/ElegantRL/helloworld/env.py", line 24, in step
state, reward, done, info_dict = self.env.step(action * 2)
ValueError: too many values to unpack (expected 4)
```
Can you help me to solve these problems?
Thanks