Explain to me a Python Code

I am trying to understand trading environments available on github. I want someone who can explain these codes to me line by line and also help me modify the same.

https://github.com/AminHP/gym-anytrading/blob/master/gym_anytrading/envs/trading_env.py
https://github.com/AminHP/gym-anytrading/blob/master/gym_anytrading/envs/stocks_env.py
https://github.com/AminHP/gym-anytrading/blob/master/gym_anytrading/envs/forex_env.py