There is not test for negative numbers.
There is no test for negative numbers, this test will fail some solutions:
checkio([-1, 2, 3], 3)
http://www.checkio.org/mission/bigproduct/publications/vagante/python-3/first/ http://www.checkio.org/mission/bigproduct/publications/jarronshih/python-3/first/ http://www.checkio.org/mission/bigproduct/publications/gyahun_dash/python-3/first/
task.bigproduct