Sanitizing params immediately before requests, I like it.

Coding preference question, why the dislike of intermediate vars?  Say

    response = super(HTTPService, self).request(**self.sanitize_request_params(request_params))

vs

    sanitized_params = self._sanitize_request_params(request_params)
    response = super(HTTPService, self).request(**sanitized_params)

I find the intermediate var in the second snippet not only breaks a long line of code but add a lot of readability.