There is `seqNum` in [line 27 of balance.py](https://github.com/HuobiRDCenter/huobi_Python/blob/66f70b04eee70c9af912011da13e596d3e44d0c2/huobi/model/account/balance.py#L27), while it has to be `seq_num` as in [line 20 of balance.py](https://github.com/HuobiRDCenter/huobi_Python/blob/66f70b04eee70c9af912011da13e596d3e44d0c2/huobi/model/account/balance.py#L20).