def count_sents(self, sents, verbose=False):
        """
            sents : a list of sentences, each a list of tokenized symbols
        """
        if verbose:
            print('counting {} sents ...'.format(len(sents)))
        for idx, symbols in enumerate(sents):
            if verbose and idx > 0 and idx % 500000 == 0:
                print('    line {}'.format(idx))
            self.counter.update(symbols)

            sents : a list of sentences, each a list of tokenized symbols
        
analyze/convnexts4nd/src/dataloaders/utils/vocabulary.py