[graph-tool] Stable topological sort in graph_tool

Hi, list. Lets call a topological sort of a graph stable, if it preserves some total ordering of nodes, if the topological order for these nodes is not defined. The StackOverflow question [1] captures the problem, and the pshufb's answer seems correct to me. How would you implement such a sort using graph_tool, which AFAIK has only an "unstable" version? Would it be possible to run 'topological_sort' on a copied graph with additional edges in it? BR, Sergey [1] https://stackoverflow.com/questions/11230881/stable-topological-sort