Indeed, since this is an internal system validating the uni's own emails it could easily query the uni's MSA for valid addresses.
Although for a set of 80k items and long-running processes (fcgi or wsgi) you could also load the whole thing in memory directly and not bother with a custom `__contains__`.
Although for a set of 80k items and long-running processes (fcgi or wsgi) you could also load the whole thing in memory directly and not bother with a custom `__contains__`.