Write backtest for trading strategy - Python

I have provided the shell code .ipynb file.

- You have to write back-test function that loops over all the stocks and in each loop increments the end date by 4 weeks and checks to see if any stock can be bought.
- The end date should end at current date after looping. It should also sell the previously bought(4 weeks back) stocks at current price.
- Then graph the P&L and return profitable trades/losing trades ratio.
- It should have initial capital variable like 10,000 or something.