code: def vlan_id(self):
          
          nicids = self.nicid.split('-')
          if nicids:
              u = []
              for vlan in nicids:
                  if vlan.split('.')[-1] not in u:
                      u.append(vlan.split('.')[-1])
              return '-'.join(u)
docs: VLAN ID for this interface, if any
          
          :return: VLAN identifier
          :rtype: str