Error occurs in PaperTrading_Demo notbook while running on Colab

**Describe the bug**
The bugs occur in Part 2 Train the agent while running train cell.
The error message is ValueError: Too many values to unplack (expected 4) occurs in function explore_env. Here is the message:

ValueError Traceback (most recent call last)
[](https://localhost:8080/#) in ()
----> 1 train(start_date = '2022-08-25',
2 end_date = '2022-08-31',
3 ticker_list = ticker_list,
4 data_source = 'alpaca',
5 time_interval= '1Min',

3 frames
[](https://localhost:8080/#) in train(start_date, end_date, ticker_list, data_source, time_interval, technical_indicator_list, drl_lib, env, model_name, if_vix, **kwargs)
57 )
58 model = agent.get_model(model_name, model_kwargs=erl_params)
---> 59 trained_model = agent.train_model(
60 model=model, cwd=cwd, total_timesteps=break_step
61 )

[](https://localhost:8080/#) in train_model(self, model, cwd, total_timesteps)
74 model.cwd = cwd
75 model.break_step = total_timesteps
---> 76 train_agent(model)
77
78 @staticmethod

[](https://localhost:8080/#) in train_agent(args)
315 torch.set_grad_enabled(False)
316 while True: # start training
--> 317 buffer_items = agent.explore_env(env, args.horizon_len)
318
319 torch.set_grad_enabled(True)

[](https://localhost:8080/#) in explore_env(self, env, horizon_len)
200
201 ary_action = convert(action).detach().cpu().numpy()
--> 202 ary_state, reward, done, _ = env.step(ary_action)
203 if done:
204 ary_state = env.reset()

ValueError: too many values to unpack (expected 4)

The following is the process for how this error comes out. I think it is from step 3 where I did wrong.

There were some bugs occurred while running on Colab. Those were
1. no attribute of `pd.Timedelta(str).delta` in /usr/local/lib/python3.10/site-packages/finrl/meta/data_processors/processor_alpaca.py -> Fixed by revising it to `pd.Timedelta(str).value`
2. ValueError: Parameter start received with timezone defined as 'UTC' although a Date must be timezone naive. -> Fixed by adding this line in 376 `ts = ts.tz_localize(None)` to /usr/local/lib/python3.10/site-packages/exchange_calendars/calendar_helpers.py
3. TypeError: tuple indices must be integers or slices, not tuple -> Fixed by deleting `[np.newaxis, :]` in line 309 `agent.states = env.reset()[np.newaxis, :]`

Not sure how to debug this error. Also, welcome any suggestions for these debugging approaches.