def get_next_id(self):
        try:
            query = {'_id': 'last_id'}
            update = {'$inc': {'id': 1}}
            fn = self.db.internal.find_and_modify
            row = fn(query, update, upsert=True, new=True)
        except Exception as e:
            raise DatabaseException(e)
        return row['id']
def define_tables(cls, metadata):
        Table(
            "table1",
            metadata,
            Column(
                "id", Integer, primary_key=True, test_needs_autoincrement=True
            ),
            Column("data", String(30)),
        )
        Table(
            "table2",
            metadata,
            Column(
                "id", Integer, primary_key=True, test_needs_autoincrement=True
            ),
            Column("someid", None, ForeignKey("table1.id")),
        )