human
Solve the following python programming problem given the following code:
@ mock.patch ('shade.OpenStackCloud.nova_client') 
def test_delete_server_wait_for_notfound(self, nova_mock) : 
    '
        Test that delete_server waits for NotFound from novaclient
        ' 
    server = fakes.FakeServer ('9999', 'wily', 'ACTIVE') 
    nova_mock.servers.list.return_value = [_delete_wily] 
    def _delete_wily(* args, **kwargs) : 
        self.assertIn ('server', kwargs) 
        self.assertEqual ('9999', kwargs ['server']) 
        nova_mock.servers.list.return_value = [] 
        def _raise_notfound(* args, **kwargs) : 
            self.assertIn ('server', kwargs) 
            self.assertEqual ('9999', kwargs ['server']) 
            raise nova_exc.NotFound (code = '404') 
nova_mock.servers.get.side_effect = _raise_notfound 
nova_mock.servers.delete.side_effect = _delete_wily 
    self.assertTrue (self.cloud.delete_server ('wily', wait = True)) 
    nova_mock.servers.delete.assert_called_with (server = server.id) 

    
    

    Fix the buggy line: nova_mock.servers.list.return_value = [_delete_wily]
assistant
#Here is Python code to fix the buggy line: nova_mock.

nova_mock.servers.list.return_value = [server]