Comment 2 for bug 1012434

I am actually not sure that we need to write complex attributes to GraphML or GML files. If the files written by Python-igraph can be interpreted only by Python-igraph, and the same is true for R, then what is the point of the whole thing?

GML can store complex attributes, it has a list data type, which may contain strings, numbers or other lists. So I think it would be better to convert Python and R lists to GML (whenever possible) lists and back. Does GraphML have some thing similar?