Not the best looking chunk of code :P thats why I made a second attemp

I really like this approach, however this solution fails the single bus scenario

def test_single_adult_scenario(self):
    kids = 40
    adults = 9
    places = 12
    expected_result = 5

    result = buses(kids, adults, places)

    assert result == expected_result # the result is 0, the expected is 5