def three(self):
pass<EOL>
Grand parent: three.

::

    >>> print("Grand parent: three.")

::

    >>> import uqbar.graphs
    >>> g = uqbar.graphs.Graph()
    >>> n1 = uqbar.graphs.Node()
    >>> n2 = uqbar.graphs.Node()
    >>> g.extend([n1, n2])
    >>> e = n1.attach(n2)

::

    >>> print(format(g, "graphviz"))

::

    >>> uqbar.graphs.Grapher(g)()  # doctest: +SKIP

And that, my friends, is a graph.