Oh, right, this is actually kind of complicated logic :)

In this case, a method could be considered "not implemented" for two different reasons, and it matters which one:
* If the module that would contain the method is not loaded, the method is not considered implemented for obvious reasons. In this case, we can't know if it would be implemented so we do not raise an error.
* If the module that would contain the method *is* loaded *and* that loaded module does not have the method implemented, we raise an error.

If we just ask `method_reference` is the method is defined, it'll give back a `false` in both cases but we won't know which it is.

I'm definitely willing to think about improving the API here. I hope I've framed it better, so let me know if you have suggestions. I'll continue mulling it over too.