[Question] How to implement object methods?

I want to try to implement `hashlib` (PR will follow).

For now I have implemented `Type`, `module`, module method and some "magic methods", but I cannot figure out how to implement object methods such as `update`, `hexdigest` etc.

Here is my WIP [implementation](https://github.com/bbrodriges/gpython/compare/master...stdlib_hashlib).

Thanks in advance.