'Returns a list of possible tenses for the given inflected verb.'

def tenses(self, verb, parse=True):

    verb = verb.lower()
    a = set()
    b = self.lemma(verb, parse=parse)
    v = []
    if (b in self):
        v = self[b]
    elif (parse is True):
        v = self.find_lexeme(b)
    for (i, tense) in enumerate(v):
        if (tense == verb):
            for (id, index) in self._format.items():
                if (i == index):
                    a.add(id)
            for (id1, id2) in self._default.items():
                if (id2 in a):
                    a.add(id1)
            for (id1, id2) in self._default.items():
                if (id2 in a):
                    a.add(id1)
    a = (TENSES[id][:(-2)] for id in a)
    a = Tenses(sorted(a))
    return a
