Same email simply isn't a type, so using the world type is confusing. What it really does is describes what should be considered a match and triggers the appropriate algorithm to be used. It should really be called an "algorithm name", "algorithm descriptor", or "algorithm selector".

I think this description also is likely to get you a function written to match by email and that's it. I'm not sure if that would be an indicator of a lack of enthusiasm for the project or not enough implication that the result of this project should go beyond the most basic example.