pydot

  edge_list = [
                ('0', '1a'),
                ('0', '2'),
                ('2', '1a'),
                ('2', '2'),
              ]
  g = pydot.graph_from_edges(edge_list, directed=True)
  g.write_raw('test.dot')

generates

digraph G {
0 -> "1a";
0 -> 2;
2 -> "1a";
2 -> 2;
}