After getting "a" and "b" values from Regression method, I have added the column history['line']=a*history.index + b to the history DataFrame.
Thus, I am able to plot the last 30 opens and this line in the same chart, in QuantBook, as follow:
history['line'].plot(), history['open'].plot()
I am not able to the same in my main.py algorithm.
Could anyone help me?

Author