From noun to verb

[MattaFX]

I tried it and got this:

    noun = gn.lemmatise(noun)
    poss_verb = ""
    while gn.synsets(poss_verb, pos='v') == []:
        try:
            if noun[-2:] == "st":
                poss_verb = noun + "eln"
                continue
            elif noun[-2:] == "st":
                poss_verb = "fasten" # test
                continue
        except:
            return []

But: the second if-condition is never reached...could you tell me why? And would you implement the rules ("ohne Umlaut", http://www.canoo.net/services/Wordformat...uffig.html) the same way or how would you do that?