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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def fit(self, sents, **kwargs):
 """Builds a vocabulary object based on the tokens in the input. Args: sents: A list of lists of tokens (representing sentences) Vocab kwargs include: max_size min_freq specials unk_init """

        tokens = list(itertools.chain.from_iterable(sents))
        counter = Counter(tokens)
        self.vocab = self.build_vocab(counter, **kwargs)