Ah that's entirely unobvious from the change. There's no comment noting that and we never received a bug report about it. There's no public API for this and I'm not convinced there should be frankly. The `try/except` class may be the better option.

We should also plan to change that error. `RuntimeError`s really shouldn't be raised by libraries or anything else. To be backwards compatible we could inherit from it, but we really should rename that to a more specific error.