Replace datetime.utcnow.
To read more about why and how, please see https://blog.miguelgrinberg.com/post/it-s-time-for-a-change-datetime-utcnow-is-now-deprecated
Edited by Tom Vaughan
To read more about why and how, please see https://blog.miguelgrinberg.com/post/it-s-time-for-a-change-datetime-utcnow-is-now-deprecated