"Logging Error: name 'statistics' is not defined" in FinRL_Ensemble_StockTrading_ICAIF_2020.ipynb

**Describe the bug**
While running `FinRL_Ensemble_StockTrading_ICAIF_2020.ipynb` with no changes (apart from incl. `!pip install pandas_market_calendars`), I received the following:

```
============Start Ensemble Strategy============
============================================
turbulence_threshold: 201.71768967803703
======Model training from: 2010-01-01 to 2021-10-04
======a2c Training========
{'n_steps': 5, 'ent_coef': 0.005, 'learning_rate': 0.0007}
Using cuda device
Logging to tensorboard_log/a2c/a2c_126_2
Logging Error: name 'statistics' is not defined
Logging Error: name 'statistics' is not defined
Logging Error: name 'statistics' is not defined
Logging Error: name 'statistics' is not defined
Logging Error: name 'statistics' is not defined
...
Logging Error: name 'statistics' is not defined
Logging Error: name 'statistics' is not defined
-------------------------------------
| time/ | |
| fps | 72 |
| iterations | 100 |
| time_elapsed | 6 |
| total_timesteps | 500 |
| train/ | |
| entropy_loss | -41.4 |
| explained_variance | 1.19e-07 |
| learning_rate | 0.0007 |
| n_updates | 99 |
| policy_loss | -60.5 |
| reward | 0.7461243 |
| reward_max | None |
| reward_mean | None |
| reward_min | None |
| std | 1.01 |
| value_loss | 3.61 |
-------------------------------------
Logging Error: name 'statistics' is not defined
Logging Error: name 'statistics' is not defined
...
Logging Error: name 'statistics' is not defined
Logging Error: name 'statistics' is not defined
--------------------------------------
| time/ | |
| fps | 78 |
| iterations | 200 |
| time_elapsed | 12 |
| total_timesteps | 1000 |
| train/ | |
| entropy_loss | -41.4 |
| explained_variance | 0 |
| learning_rate | 0.0007 |
| n_updates | 199 |
| policy_loss | -84.3 |
| reward | 0.83888245 |
| reward_max | None |
| reward_mean | None |
| reward_min | None |
| std | 1.01 |
| value_loss | 12.3 |
--------------------------------------
Logging Error: name 'statistics' is not defined
Logging Error: name 'statistics' is not defined
...
Logging Error: name 'statistics' is not defined
--------------------------------------
| time/ | |
| fps | 84 |
| iterations | 300 |
| time_elapsed | 17 |
| total_timesteps | 1500 |
| train/ | |
| entropy_loss | -41.4 |
| explained_variance | 0 |
| learning_rate | 0.0007 |
| n_updates | 299 |
| policy_loss | -96.5 |
| reward | -1.7435927 |
| reward_max | None |
| reward_mean | None |
| reward_min | None |
| std | 1.01 |
| value_loss | 12.3 |
--------------------------------------
```

while running the cell:

```
df_summary = ensemble_agent.run_ensemble_strategy(A2C_model_kwargs,
PPO_model_kwargs,
DDPG_model_kwargs,
SAC_model_kwargs,
TD3_model_kwargs,
timesteps_dict)
```

While it does continue to run as expected in between the multitude of logging errors, not sure what I could be doing wrong/changed since this Notebook's implementation.

Thanks in advance!