William Davis9,015 Points
How would we deal with users asking for a negative amount of tickets (eg: -1 tickets)?
The exception raised is great for users who want to order more tickets than available and for users who write something other than a positive number, but it doesn't work if I say that I want -1 tickets, as the script continues and even adds it to the number of tickets remaining.
How would we deal with this situation?
Steven Parker173,943 Points
You can easily add another test & raise similar to the one for excessive tickets, right above or right below the existing one:
if num_tickets < 1: raise ValueError("We cannot sell less than 1 ticket!")
For better efficiency, the second test can be changed to an "elif", since both conditions can't be true at the same time.