Errors in 1-Introduction/Stock_NeurIPS2018_3_Backtest.ipynb

1. Where is 'processed_full' defined?
```
----> 1 data_risk_indicator = processed_full[(processed_full.date=TRAIN_START_DATE)]
2 insample_risk_indicator = data_risk_indicator.drop_duplicates(subset=['date'])
NameError: name 'processed_full' is not defined
```

2. Where is the file 'agent_a2c.zip'?
```
----> 1 trained_a2c = A2C.load("agent_a2c") if if_using_a2c else None
2 trained_ddpg = DDPG.load("agent_ddpg") if if_using_ddpg else None
FileNotFoundError: [Errno 2] No such file or directory: 'agent_a2c.zip'
```

I countered above error when I followed the tutorial (https://finrl.readthedocs.io/en/latest/start/first_glance.html). But every Colab notebook example reads files created from the previous example and sometimes non-existing files too. I am afraid that I cannot continue the tutorial.

Can I let the current Colab notebook read files created from the previous Colab notebok example?