How to import errors in the new Python API

I used to do

if isinstance(e, openai.error.RateLimitError):
                raise Exception("Rate limit exceeded too many times.") from e
            elif isinstance(e, openai.error.ServiceUnavailableError):
                raise Exception("Service unavailable too many times.") from e
                raise e

However, openai.error no longer exists (contradicting this page).

Now, it looks like I can do openai.RateLimit instead of openai.error.RateLimitError, but openai.ServiceUnavailableError does not exist. Where did it go?

How can I find out where to import each error type?