Cannot fetch stock data from yahoofinance

[Tiger-77]

Hi, Krivi95! Nice work! Your model is of great help. But I confronted with some problems when testing the code.

I ran option_price_test.py and I found the output of the following statement is None

'''
print(Ticker.get_columns(data))
print(Ticker.get_last_price(data, 'Adj Close'))
'''
Also, I could not draw the graph of the stock price.

Thanks,
Tiger77