How to use the ogame.constants.Ships.values function in ogame

def build_ships(self, planet_id, ship_id, nbr):
        """Build a ship unit."""
        if ship_id not in constants.Ships.values():
            raise BAD_SHIP_ID

        url = self.get_url('shipyard', {'cp': planet_id})

        res = self.session.get(url).content
        if not self.is_logged(res):
            raise NOT_LOGGED
        soup = BeautifulSoup(res, 'html.parser')
        form = soup.find('form')
        token = form.find('input', {'name': 'token'}).get('value')

        payload = {'menge': nbr,
                   'modus': 1,
                   'token': token,
                   'type': ship_id}
        self.session.post(url, data=payload)

def _build(self, planet_id, object_id, nbr=None, cancel=False):
        if object_id in constants.Buildings.values() or object_id in constants.Facilities.values():
            self.build_building(planet_id, object_id, cancel=cancel)
        elif object_id in constants.Research.values():
            self.build_technology(planet_id, object_id, cancel=cancel)
        elif object_id in constants.Ships.values():
            self.build_ships(planet_id, object_id, nbr)
        elif object_id in constants.Defense.values():
            self.build_defense(planet_id, object_id, nbr)