'Smoothing method 2: Add 1 to both numerator and denominator from
Chin-Yew Lin and Franz Josef Och (2004) Automatic evaluation of
machine translation quality using longest common subsequence and
skip-bigram statistics. In ACL04.'

def method2(self, p_n, *args, **kwargs):

    return [Fraction((p_i.numerator + 1), (p_i.denominator + 1), _normalize=False) for p_i in p_n]
