I added the parentheses to the `db.session.rollback` line to call the method, which will now properly roll back any changes made to the database if an error occurs.
The implementation of `random.choice()` uses the Mersenne Twister, the
output of which is predictable by observing previous output, and is as
such unsuitable for security-sensitive applications. A cryptographically
secure pseudorandom number generator - which the `secrets` module relies
on - should be used instead in those instances.
