tests are all showing that I passed, yet I failed?

I would like to give some feedback about ...

From: https://checkio.org/mission/golden-pyramid/solve/

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For this puzzle, I see the response for 8 basic tests and 11 extra tests all saying that I passed, yet, it is telling me that I failed. I don't understand why.

Here is the contents of pyramid.py if that helps.

def count_gold(pyramid):
    paths = {"0-0":pyramid[0][0]}
    for y in range(len(pyramid)):
        line = pyramid[y]
        for x in range(len(line)):
            if (y +1 != len(pyramid)):
                keys = [x for x in paths.keys()]
                for key in keys:
                    if key.find("%s-%s"%(x,y)) != -1:
                        nY = y + 1
                        for dx in range(2):
                            nX = x + dx
                            newKey = key + ",%s-%s"%(nX, nY)
                            paths[newKey] = paths[key] + pyramid[nY][nX]
    values = []
    for key in paths.keys():
        values += [paths[key]]
    rtn = max(values)

    return rtn



    """
    Return max possible sum in a path from top to bottom
    """

    #replace this for solution
    return 0


if __name__ == '__main__':
    #These "asserts" using only for self-checking and not necessary for auto-testing
    assert count_gold((
        (1,),
        (2, 3)
        )) == 4, "simple example"

    assert count_gold((
        (1,),
        (2, 3),
        (3, 3, 1),
        (3, 1, 5, 4),
        (3, 1, 3, 1, 3),
        (2, 2, 2, 2, 2, 2),
        (5, 6, 4, 5, 6, 4, 3)
    )) == 23, "First example"
    assert count_gold((
        (1,),
        (2, 1),
        (1, 2, 1),
        (1, 2, 1, 1),
        (1, 2, 1, 1, 1),
        (1, 2, 1, 1, 1, 1),
        (1, 2, 1, 1, 1, 1, 9)
    )) == 15, "Second example"
    assert count_gold((
        (9,),
        (2, 2),
        (3, 3, 3),
        (4, 4, 4, 4)
    )) == 18, "Third example"