def test_size_2():
g = Graph()
g.add_node(235235)
g.add_node(3232)
g.add_node(222)
actual = g.size()
expected = 3
assert actual == expected
def test_size_1():
g = Graph()
g.add_node(1)
actual = g.size()
expected = 1
assert actual == expected
def test_size_none():
g = Graph()
actual = g.size()
expected = None
assert actual == expected