would it help if we made it easier to set the exception attributes, so you can raise

raise InvalidArgument(message, ArgumentName=name, ArgumentValue=value)

?

there are two ways that we can do that. either we change the scaffold to create the constructors of exceptions accordingly, or we extend the ServiceException constructor to accept kwargs, to something like:

    def __init__(self, *args, **kwargs):
        super(ServiceException, self).__init__(*args)

        if len(args) >= 1:
            self.message = args[0]
        else:
            self.message = ""
         
        for k,v in kwargs.items():
            setattr(self, k) = v

the second option is simpler and also easier to implement, however it makes it harder to subclass or customize the constructor. the first approach would maybe be cleaner but also a bit more effort.

Right! I think right now, it's not exactly needed, as it concerns only S3. I'm thinking about maybe creating a new file exceptions.py for s3, with the helpers to create the necessary exceptions.
I have some kind of a weird case here with presigned URLs: some exceptions have a lot of members (up to 7 I think), but some fields are not returned nor created, depending on the kind of exceptions. So attaching conditionally the members is quite practical.
If I document it better, maybe it can just be know for s3 that you need to create the exceptions with the helper methods. And I like being able to add some logic while creating the exceptions, like the Bytes version of the field.
Presigned URL exception example: