At check-in you say the weight limit, then put the bags on the scale one by one: over_limit(20, 8, 9, 5). Write over_limit(limit, *bags) to return how many kilos over you are; if you're not over, or there are no bags at all, return 0.
over_limit(20, 8, 9, 5)→2over_limit(20)→0def over_limit(limit, *bags):
total = 0
# your code here: add up all the bag weights into total
if total > limit:
# your code here: return how many kilos over
pass
return 0
Run tries the examples. When they look right, Submit.