def METHOD_NAME(self):
    model = test_models_keras.simple_functional()
    # When creating Functional model, it should have to define input information
    # Therefore, there is no case where there is no input information in the Functional model
    for layer in model.layers:
        assert layer.inbound_nodes
    connected_graph = ConnectedGraph(model)
    for layer in connected_graph._model.layers:
        assert layer.inbound_nodes
    assert len(connected_graph.get_all_ops().keys()) == 2