human
Solve the following python programming problem given the following code:
@ mock.patch.object (seamicro, '_get_server', autospec = True) 
def test_set_node_vlan_id_fail(self, mock_get_server) : 
    def fake_set_untagged_vlan(self, **kwargs) : 
        raise seamicro_client_exception.ClientException (http_client.INTERNAL_SERVER_ERROR) 
vlan_id = '12' 
    server = self.Server (active = 'true') 
    server.set_untagged_vlan = <MASK> 
    mock_get_server.return_value = server 
    with task_manager.acquire (self.context, self.info ['uuid'], shared = False) as task : 
        kwargs = { 
            'vlan_id' : vlan_id, 
} 
        self.assertRaises (exception.IronicException, task.driver.vendor.set_node_vlan_id, task, ** kwargs) 
mock_get_server.assert_called_once_with (self.info) 
    
    Given the code above, what is a proper replacement for <MASK>? Choose among: server, vlan_id, mock_get_server, kwargs, self, task
assistant
#Here is a proper replacement for <MASK>.
def fake_set_untagged_vlan(