def test_tag_nodes(self):
    tagged_node = node(identity, 'input', 'output', tags=['hello']).tag(['world'])
    assert ('hello' in tagged_node.tags)
    assert ('world' in tagged_node.tags)
    assert (len(tagged_node.tags) == 2)
def test_tag_nodes(self):
    tagged_node = node(identity, 'input', 'output', tags=['hello']).tag(['world'])
    assert ('hello' in tagged_node.tags)
    assert ('world' in tagged_node.tags)
    assert (len(tagged_node.tags) == 2)