High level objects

Currently, the client returns JSONs. It would be better to return high level types. Examples: [bancointer](https://github.com/lucasrcezimbra/bancointer/blob/master/inter/_inter.py#L67) and [python-eduzz](https://github.com/HBNetwork/python-eduzz/blob/main/eduzz/client/financial/__init__.py#L20-L22)