OSM to DIRECTED Graph (python-igraph / networkx)

I am using this python script to download OSM data and convert it to an undirected networkx graph:

http://ift.tt/1g1rfGF

However,in the ideal case, I would like to generate a directed graph from it in order to refelct the directionality of the osm street network.

First of all, can you confirm that as stated here and here in OSM raw xml data, the order of the nd-entries in the way is what matters for the direction?

And secondly, how would you suggest to implement the generation of a directed graph from the osm raw data, give the the above gist code snippet as a template?

many thanks!