Sadly I wasn't able to do so, because of this error:
AttributeError: 'list' object has no attribute 'get_bstack'
While trying to find a solution, I discovered further Information:
"list.clear() is not in Python 2, only in Python 3. The example runs without problem in Python 3. Anyway, graph-tool is supposed to work on Python 2.7 and above, so this might as well be reported as a bug."