def _diff_sequences(a, b, path):
    if (len(a) != len(b)):
        return [(path[:], a, b)]
    returned = []
    for (i, a_i) in enumerate(a):
        path.append(i)
        returned.extend(diff(a_i, b[i], path))
        path.pop()
    return returned
def _diff_sequences(a, b, path):
    if (len(a) != len(b)):
        return [(path[:], a, b)]
    returned = []
    for (i, a_i) in enumerate(a):
        path.append(i)
        returned.extend(diff(a_i, b[i], path))
        path.pop()
    return returned