Graph set_simplify has bug ?

[puruta]

Graph to_string method makes exception when i used set_simplify.

File "/usr/lib/python2.5/site-packages/pydot.py", line 1458, in
to_string
if self.obj_dict.get('simplify', False) and elm in edges_done:

in graph.to_string(), to remove duplicate edges , pydot is using
edges_done as set().

And this set's element is edge object. I think this set object has to
keep string of edge.to_string().

Thanks,