Personnummer checksum verification

[Anton Ekblad]

Fire currently doesn't seem to verify that personnummer entered are actually personnummer. Shouldn't it do that?

Attaching the algorithm to verify personnummer described in Haskell; it's slightly different from the one given on the Wikipedia page for Luhn checksums and I couldn't find a good reference in English.

[Evgeny Kotelnikov]

Thanks! If you would be willing to translate it to Python and make a pull request, the relevant place in the code is here.

Also relevant: https://bitbucket.org/cse-fire/fire/issue/63/personnumers-should-not-be-mandatory (albeit I heard that students are given some temporary personnummers after all).