support for object arguments

[Panaetius]

It'd be great if something like this worked:

class User:
    name: str
    email: str

class UserExecutor(...):
    @query("""
        INSERT INTO user (name, email) VALUES ($user.name, $user.email);
    """)
    async def mayim_insert_user(user: User)-> None:
        ...

[ahopkins]

Interesting idea 🤔