def METHOD_NAME():
    probability1 = Probability(0.2)
    probability2 = Probability(0.3)
    assert approx(0.5) == Probability.sum((probability1, probability2))
    assert approx(0.5) == Probability.sum((0.2, probability2))
    assert approx(0.5) == Probability.sum((probability1, 0.3))
    assert approx(0.5) == Probability.sum((probability1, probability2, 0))
    assert approx(0.2) == Probability.sum((Probability(0), probability1))
    assert 0 == Probability.sum((Probability(0), ))
    assert 0 == Probability.sum([])