def METHOD_NAME(self):
    samples = [[1, 2, 3], [6]]
    sample_spaces = [[1, 2, 3, 4], [5, 6]]
    combos = generate_combo(samples, sample_spaces)
    expected = 1
    for sample, sample_space in zip(samples, sample_spaces):
        expected *= comb(len(sample_space), len(sample), exact=True)
    # we leave out the original combination
    expected -= 1
    assert len(combos) == expected