I have the following code:

import numpy as np 
import pandas as pd
import yfinance as yf
from yahoofinancials import YahooFinancials

yahoo_financials = YahooFinancials('BTC-USD')
data = yahoo_financials.get_historical_price_data("2014-09-17", "2021-11-15", "daily")
btc = pd.DataFrame(data['BTC-USD']['prices'])
btc = btc.drop('date', axis=1).set_index('formatted_date')

However, running the last line of code gives me the following error: TypeError: int() argument must be a string, a bytes-like object or a number, not '_NoValueType'. I am aware that the errore is quite popular. The issue is that all the solutions I tried aren't working. I tried to convert the column of interest into int(), str() or float() but unable to sort this out.

What am I doing wrong?

Thanks!