Can't create two-directional edges: 'lost B A edge'

[Risto H. Kurppa]

Kubuntu 11.04
python-pygraphviz 1.0-1build1 from Ubuntu repositories.

My DOT file:
strict digraph graphName {
concentrate=true
A->B
B->A
}

it compiles OK with dot:
dot simple2.dot -Tpng:cairo:gd -o testi.png

but when I try it with pygraphviz:

#!/usr/bin/env python
import pygraphviz as pgv
B=pgv.AGraph('simple2.dot') # create a new graph from file
B.layout() # layout with default (neato)
B.draw('simple.png') # draw png

I get this:

/usr/lib/pymodules/python2.7/pygraphviz/agraph.py:1170: RuntimeWarning: Error: lost B A edge

  warnings.warn("".join(errors),RuntimeWarning)

and the generation is aborted.

Removing or commenting the concentrate -line from the .dot file, the output is generated but with two one-headed arrows instead of one two-headed.

[Matthias Klose (doko)]

11.04 is obsolete. please recheck with newer versions.