def to_dict(self):
        d = {}
        for batch in self:
            table_name, batch_dict = batch.to_dict()
            d[table_name] = batch_dict
        return d
Convert a BatchWriteList object into format required for Layer1.
dataset/ETHPy150Open darcyliu/storyboard/boto/dynamodb/batch.py/BatchWriteList.to_dict