Now that our program is working as expected, all that's left to do is to notify our customers when there is a good deal!
1. Create a method in the NotificationManager called send_emails() . Use what you have learnt about smtplib and sending emails to send all our customers in the users sheet from Google Sheets the message that contains the flight deal.
NOTE: when sending emails, it won't like the "" symbol, you might get an error like the one below:

You can solve this by encoding the message with UTF-8 e.g. https://stackoverflow.com/questions/9942594/unicodeencodeerror-ascii-codec-cant-encode-character-u-xa0-in-position-20#answer-9942885