def _batch_iterator(self, N=1):
        batch_size = math.ceil(self.num_records / float(N))
        handle = self._open(self.filename)
        while True:
            batch = list(islice(handle, batch_size))
            if not batch:
                break
            yield batch
Returns N lists of records.
dataset/ETHPy150Open tanghaibao/jcvi/formats/base.py/FileSplitter._batch_iterator