after thinking about it some more, i was skeptical that this really implements bubble sort, but after trying it, it does

python version of the inner loop

    max_ = arr[0]
    for j in range(1, i):
        y = arr[j]
        arr[j - 1] = min(max_, y)
        max_ = max(max_, y)

    arr[i - 1] = max_