even_odd while loop Challenge Task 3 of 3 problem

I had no problem with task 1 and 2 but after I coded the while loop the 'check work' would only ever tell me that task 1 was no longer going through. I wrote the code in workspace to get better trouble shooting; changed a few things to make it run properly, and checked it again. But now it only gives me 'Bummer! Try again!' (After trying different things, it seems that having the 'start' variable outside my function is causing the 'Task 1 no longer going through' message, but inside it goes back to 'Bummer! Try again!')

Not really sure what to change as I am sure the code runs, having ran it in workspaces. As there aren't any other questions about this challenge I feel like I'm probably missing something incredibly obvious. :P

Any help would be greatly appreciated. :)

import random
num = 0

def even_odd(num):
    # If % 2 is 0, the number is even.
    # Since 0 is falsey, we have to invert it with not.
    return not num % 2

def prev(num):
    start = 5
    while start != 0:
        start = start-1
        num = random.randint(1, 99)
        renum = even_odd(num)
        if renum == True:
            print('{} is even!'.format(num))
        else:
            print('{} is odd!'.format(num))

prev(num)