code: def _strip_list_attributes(graph_):
      
      for n_ in graph_.nodes(data=True):
          for k,v in n_[1].iteritems():
              if type(v) is list:
                  graph_.node[n_[0]][k] = unicode(v)
      for e_ in graph_.edges(data=True):
          for k,v in e_[2].iteritems():
              if type(v) is list:
                  graph_.edge[e_[0]][e_[1]][k] = unicode(v)
  
      return graph_
docs: Converts lists attributes to strings for all nodes and edges in G.