def METHOD_NAME(self):
    data = {2: set([11]),
            9: set([11, 8]),
            10: set([11, 3]),
            11: set([7, 5]),
            8: set([7, 3, 8]),  # includes something self-referential
            }
    orig = data.copy()
    results = list(toposort(data))
    assert data == orig