<gh_stars>1-10
D = DiGraph(multiedges=True, sparse=True)
for i in range(5):
     D.add_edge((i, i + 1, 'a'))
     D.add_edge((i, i - 1, 'b'))
sphinx_plot(D.graphplot(edge_labels=True,
                        edge_colors=D._color_by_label()))