How to use the smt.decoder.stackdecoder.ArgumentNotSatisfied function in smt

(5, 5): Frac(-14, 10),
                       (6, 6): Frac(-1),
                       (7, 7): Frac(-1),
                       (8, 8): Frac(-19, 10),
                       (9, 9): Frac(-16, 10),
                       (3, 4): Frac(-4),
                       (5, 6): Frac(-25, 10),
                       (7, 8): Frac(-22, 10),
                       (6, 7): Frac(-13, 10),
                       (8, 9): Frac(-24, 10),
                       (5, 7): Frac(-27, 10),
                       (6, 8): Frac(-23, 10),
                       (7, 9): Frac(-23, 10),
                       (6, 9): Frac(-23, 10),
                       }
        self.assertRaises(ArgumentNotSatisfied,
                          _future_cost_estimate,
                          sentences,
                          phrase_prob)

def _future_cost_estimate(sentences,
                          phrase_prob):
    '''
    warning:
        pass the complete one_word_prob
    '''
    s_len = len(sentences)
    cost = {}

    one_word_prob = {(st, ed): prob for (st, ed), prob in phrase_prob.items()
                     if st == ed}

    if set(one_word_prob.keys()) != set((x, x) for x in range(1, s_len+1)):
        raise ArgumentNotSatisfied("phrase_prob doesn't satisfy the condition")

    # add one word prob
    for tpl, prob in one_word_prob.items():
        index = tpl[0]
        cost[(index, index)] = prob

    for length in range(1, s_len+1):
        for start in range(1, s_len-length+1):
            end = start + length
            try:
                cost[(start, end)] = phrase_prob[(start, end)]
            except KeyError:
                cost[(start, end)] = -float('inf')
            for i in range(start, end):
                _val = cost[(start, i)] + cost[(i+1, end)]
                if _val > cost[(start, end)]: