Jason

Results 2 issues of Jason

### Issue subject Subscribe flexible product error ### Expected behaviour Subscribe flexible product succeed ### Actual behaviour api call error ![微信图片_20240312164302](https://github.com/binance/binance-connector-python/assets/29377930/1957a5b4-2c3c-4145-a232-dbaa9f0f759e) ### Steps to reproduce call subscribe_flexible_product api ### Environment...