'Adds counts for elements in other'

def update(self, other):

    if isinstance(other, self.__class__):
        self.n_sents += other.n_sents
        for (x, n) in other.items():
            self[x] += n
    else:
        for sent in other:
            self.n_sents += 1
            if (self.poscache is not None):
                if (sent in self.poscache):
                    tags = self.poscache[sent]
                else:
                    self.poscache[sent] = tags = nltk.pos_tag(nltk.word_tokenize(sent))
            else:
                tags = nltk.pos_tag(nltk.word_tokenize(sent))
            for x in tags:
                (tok, tag) = x
                self[tag] += 1
        if self.normalize:
            for (x, n) in self.items():
                self[x] /= float(self.n_sents)
