Restricted sum: Test 2 fails but passes locally

I would like to give some feedback about ...

From: https://checkio.org/mission/restricted-sum/solve/

HTTP_USER_AGENT:

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0

q = 0

def checkio(data): global q if len(data) != 0: q = data[0] + q c = data[1:] checkio(c) return q

when i run this locally i get the correct results but checkio test 2 return 18 rather than 12.