Typos in examples. Correct versions:

assert checkio([[1, 2, 3],
         [4, 5, 6],
         [7, 8, 9]]) == [[1, 4, 7],
                         [2, 5, 8],
                         [3, 6, 9]]

assert checkio([[1, 4, 3],
         [8, 2, 6],
         [7, 8, 3],
         [4, 9, 6],
         [7, 8, 1]]) == [[1, 8, 7, 4, 7],
                         [4, 2, 8, 9, 8],
                         [3, 6, 3, 6, 1]]