code: def get(self, *args, **kwargs):
          
          if args:
              kwargs = {'vlan_id': str(args[0])}
          key, value = kwargs.popitem()
          for item in self:
              if 'vlan_id' in key and getattr(item, key, None) == value:
                  return item
              for vlan in item.interfaces:
                  if getattr(vlan, key, None) == value:
                      return item
docs: Get the sub interfaces for this VlanInterface
          
              >>> itf = engine.interface.get(3)
              >>> list(itf.vlan_interface)
              [Layer3PhysicalInterfaceVlan(name=VLAN 3.3), Layer3PhysicalInterfaceVlan(name=VLAN 3.5),
              Layer3PhysicalInterfaceVlan(name=VLAN 3.4)]
          
          :param int args: args are translated to vlan_id=args[0]
          :param kwargs: key value for sub interface
          :rtype: VlanInterface or None